FOUS11 KWBC 031900
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
200 PM EST Tue Feb 3 2026

Valid 00Z Wed Feb 04 2026 - 00Z Sat Feb 07 2026


...Ohio Valley, Central Appalachians, Mid-Atlantic, Carolinas...=20
Days 1-2...

Increasing moisture and warm air advection ahead of a weak surface
low over the Mid South combined with large-scale forcing for=20
ascent within the left exit region of a strengthening 100kt+ upper=20
level jet streak will yield a swath of snow from eastern KY eastward
to the central Appalachians tonight into early Wednesday. Amounts=20
will be light (Minor impacts per the WSSI) and WPC probabilities=20
for snowfall >2" are 30-60% mainly across the higher elevations of=20
WV and southwest VA.

Some light snow should also crest the central Appalachians into=20
parts of the Mid-Atlantic late tonight into Wednesday morning, but
this can sometimes dry up east of I-81. WPC probabilities for 1"=20
of snow are generally <15% along the I-66/Rt 50 corridor across=20
northern VA, DC, MD, and into DE. Still, any snow combined with the
recent cold could be enough to cause localized travel concerns,
particularly during the Wednesday morning commute.

As the front continues southeastward, trailing shortwave energy may
slow the southern portion of the front over the Southeast, allowing
another weak area of low pressure to form over the southern=20
Appalachians on Wednesday. As the low moves slowly through GA/SC=20
Wednesday evening and off the coast early Thursday, moisture will=20
linger over southern VA and much of northern/western NC where=20
temperatures are marginally supportive of snow. During the=20
overnight hours, dynamic cooling could support some light=20
accumulations around an inch or so across southern VA and northern
NC, especially across the higher elevations of southwestern VA and
northwest NC where WPC probabilities of >2" of snow are 20-40%.

In the wake of the departing low pressure system, lingering low-=20
level upslope moisture combined with mid-level drying may lead to a
period of freezing drizzle across parts of eastern KY, southwest=20
VA, eastern TN, and western NC late tonight into Wednesday morning.
Anywhere the freezing drizzle is more persistent could produce a=20
light glaze of ice. Additionally, enough northerly component of the
wind could drain some sub-freezing boundary layer air into far=20
southeastern VA and eastern NC, supporting light icing of around=20
0.05" or so later Wednesday night into early Thursday morning.=20
While any ice is hazardous, the icing noted above could be more=20
problematic than usual due to the recent winter storm(s).


...Great Lakes, Central Appalachians, Mid-Atlantic...=20
Day 3...

A 140kt upper level jet over south central Canada Thursday will=20
help push a warm front through the western Great Lakes, followed by
a strong Arctic cold front that will dive to the south and east across
the region through the day on Friday. The left exit region of this
jet combined with a potent vort max will increasingly support=20
large scale forcing for ascent, with weak surface low development=20
possible downstream of the western Great Lakes. This will support=20
widespread snow showers and the potential for snow squalls from
MI and western NY to OH, PA, and WV starting late Thursday night=20
and continuing through the day on Friday. Some of the stronger=20
showers and squalls are looking increasingly likely to spill over=20
the central Appalachians into parts of the Mid-Atlantic later in
the afternoon, possibly impacting the evening commute. WPC=20
probabilities for >2" of snow are 40-70% across parts of MI,=20
northeast OH, northwest PA, and the higher elevations of southwest=20
PA and WV. Probabilities for >4" of snow are 10-20% for portions of
the U.P. of MI, northeast OH, and WV.=20

In the wake of the Arctic front, a blast of bitterly cold air will
encompass much of the Northeast heading into the weekend. For more
details, please reference the Extreme Cold Key Messages in the link
provided below.


Miller/Fracasso


...Extreme Cold Key Messages are in effect. Please see current Key
Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!5j_1Fl9dotMFlsl07RquALPtLY120Rf8RXpm3UvO9h2Aq= WTyEVokCe1dREqejgH5zKFQcTSSV5HeegGtRiqqlHSH2qw$=20


$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 040716
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
216 AM EST Wed Feb 4 2026

Valid 12Z Wed Feb 04 2026 - 12Z Sat Feb 07 2026


...Southern Mid-Atlantic...
Day 1...

A cold front over the Southeast this morning and area of low=20
pressure over the southern Appalachians will make a slow march=20
eastward today with rain over much of the region but some light=20
snow on the northern side of the precipitation shield. Trailing=20
shortwave energy from the Lower MS Valley/Mid-South will slow the=20
front a bit tonight as temperatures cool just enough over southern=20
VA into northern NC for snow to fall and accumulate. In addition,=20
lingering moisture over eastern NC tonight combined with mid-level=20
drying may lead to some freezing rain and freezing drizzle. Though=20 accumulations will be light (0.01-0.05"), any freezing rain is=20
impactful to untreated surfaces. Precipitation will end from west=20
to east Thursday.

WPC probabilities of at least 2 inches of snow are 20-50% over=20
southwestern VA and barely 10% over northern/northeastern NC.=20


...Great Lakes, Central Appalachians, Northeast, Mid-Atlantic...=20
Days 1-3...

A warm front will push into the Upper Midwest and western Great=20
Lakes, aided by a 140kt upper level jet over south central Canada=20
on Thursday. Light and broad WAA-driven snow is forecast for=20
northeastern MN and across the Upper and Lower Peninsulas of=20
Michigan. This will be followed by a strong Arctic cold front that=20
will dive to the south and east across the region through the day=20
on Friday. The left exit region of this jet combined with a potent=20
vort max will support large-scale forcing for ascent across the=20
Great Lakes in the wake of the lead light snow. With the passage of
the Arctic front, snow squalls are possible from MI and western NY
to OH, PA, and WV starting late Thursday night and continuing=20
through the day on Friday. Some of the stronger showers and squalls
are looking increasingly likely to spill over the central=20
Appalachians into parts of the Mid-Atlantic later in the afternoon,
possibly impacting the evening commute on Friday. Upslope snow in=20
the central Appalachians should maximize Friday afternoon/evening=20
as the front moves through.=20

WPC probabilities for at least 4 inches of snow are low (10-40%)=20
across the U.P. of Michigan and west of Traverse City. Over western
NY and NW PA, surface low may move through the region and spur=20
more widespread snow along/behind the front and as winds turn more=20 northerly, picking up moisture off Lake Ontario. There, WPC=20
probabilities for at least 4 inches of snow are 20-50%. Finally,=20
over eastern WV, amounts will likely be the highest in the region=20
and WPC probabilities for at least 4 inches of snow are >70%,=20
especially above 2000ft.=20

In the wake of the Arctic front, a blast of bitterly cold air will
encompass much of the Northeast heading into the weekend. For more
details, please reference the Extreme Cold Key Messages in the=20
link provided below.

Fracasso


...Extreme Cold Key Messages are in effect. Please see current Key
Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!7tsD76lSRVfHX36EwdU0bUH9sv7W5vUQCPqiaIzI-ixFR= Gd4LUnOvsu70q0yzEm9RwTuYw8BtsBuDJVbB7gEJeEI6qI$=20


$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 041942
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
242 PM EST Wed Feb 4 2026

Valid 00Z Thu Feb 05 2026 - 00Z Sun Feb 08 2026


...Southern Mid-Atlantic...
Day 1...

An area of low pressure riding along a cold front that is tracking
across the Southeast will bring some wintry precipitation on the
northern fringe of the precipitation shield along the VA/NC border
tonight. Rain and a wintry mix will change over to snow, while for
portions of central and eastern North Carolina, mid-level drying
with a slow exit of the low level moisture will support a period of
freezing drizzle, which could accumulate to a few hundredths of an
inch on untreated surfaces tonight. Both precipitation and
associated impacts should end within a couple hours of sunrise
Thursday.=20

WPC probabilities of 0.01 inches of ice is around 80% for portions
of North Carolina between Greenville and Fayetteville, and up to
30% for 0.10 inches of ice. Snow probabilities for an inch of snow
are between 20-40% along the VA/NC border, and up to 50% along I-81
southwest of Roanoke, VA.=20



...Great Lakes, Central Appalachians, Northeast, Mid-Atlantic...=20
Days 1-3...

A warm front will push into the Upper Midwest and western Great=20
Lakes, aided by a 140kt upper level jet over south central Canada=20
on Thursday. Light and broad WAA-driven snow is forecast for=20
northeastern MN and across the Upper and Lower Peninsulas of=20
Michigan. This will be followed by a strong Arctic cold front that=20
will dive to the south and east across the region through the day=20
on Friday. The left exit region of this jet combined with a potent=20
vort max will support large-scale forcing for ascent across the=20
Great Lakes in the wake of the lead light snow. With the passage of
the Arctic front, snow squalls are possible from MI and western NY
to OH, PA, and WV starting late Thursday night and continuing=20
through the day on Friday. Some of the stronger showers and squalls
are looking increasingly likely to spill over the central=20
Appalachians into parts of the Mid-Atlantic later in the afternoon,
possibly impacting the evening commute on Friday. Upslope snow in=20
the central Appalachians should maximize Friday afternoon/evening=20
as the front moves through.=20

WPC probabilities for at least 4 inches of snow are low (10-30%)=20
across the U.P. of Michigan and west of Traverse City. Over western
NY and NW PA, surface low may move through the region and spur=20
more widespread snow along/behind the front and as winds turn more=20 northerly, picking up moisture off Lake Ontario. There, WPC=20
probabilities for at least 4 inches of snow are 20-40%. While there
is a considerable amount of ice cover on the Great Lakes, just
under 50% according to the USNIC, there remains enough open water
on all but Lake Erie to expect there to be at least some
contribution of lake moisture to the column as the front moves
through. In addition to upslope into the U.P. of Michigan and
western New York, higher snow totals can be expected in these
areas.

Finally, over eastern WV, amounts will likely be the highest in=20
the region and WPC probabilities for at least 4 inches of snow are=20

70%, especially above 2000ft. Considerable upslope flow with

northwesterly winds orthogonal to the Appalachians should wring out
the most atmospheric moisture, resulting in the greatest snow
totals here, hence the highest probabilities.

In the wake of the Arctic front, a blast of bitterly cold air will
encompass much of the Northeast heading into the weekend. For more
details, please reference the Extreme Cold Key Messages in the=20
link provided below.

Fracasso/Wegman



...Extreme Cold Key Messages are in effect. Please see current Key
Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!-L09wy298h8p0HixTwZRXJh9yemxGI5nIpYl1RfnPrfk3= P4EYhRUXRbBhtoQEcTsBOik16JFMlJIR31mdQRa5gP9iBg$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 050819
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
319 AM EST Thu Feb 5 2026

Valid 12Z Thu Feb 05 2026 - 12Z Sun Feb 08 2026


...The Carolinas...=20
Day 1...

A deep shortwave trough will track across the northern Gulf and
then off the Florida coast through this aftn. This will help
strengthen secondary low pressure off the coast of the Carolinas,
with some lingering moisture extending back onshore, at least
through the morning. However, forecast soundings indicate that
pronounced dry air above the surface will inhibit much in the way
of precipitation. However, what does fall, will occur in a sub-
freezing column, leading to a continuation of very light freezing
rain or freezing drizzle for a few hours after 12Z across the
eastern Carolinas. This is reflected by WPC probabilities that
indicate a 10-30% chance (locally 50% chance) of more than 0.01" of
ice, highest from Cape Fear through the Outer banks.


...Great Lakes, Central Appalachians, Northeast, Mid-Atlantic...=20
Days 1-3...

A fast moving shortwave diving out of Manitoba will race southeast
today, reaching the Mid-Atlantic states by Friday morning. This
lead impulse will be followed almost immediately by a second, more
strung out, shortwave, with this secondary impulse responsible for
driving a strong arctic cold front southward beneath it. This
secondary impulse will help develop a surface wave of low pressure
across Upstate NY Friday evening, with this low scooting rapidly
eastward to off the New England coast by the end of D2. The lead
cold front will trail off this low, with a secondary reinforcing
surge of arctic air occurring Saturday behind a secondary front.

Together, these features will result in an extended period of
moderate ascent, but in an environment with normal to below normal
PWs on the sharpening NW flow. Although the moisture will be
modest, the forcing will be sufficient to wring out snowfall across
the area, although most accumulation will be very light. There may
be a few exceptions:

1) Upslope snow into the Central Appalachians. This is expected
behind the first cold front beginning Friday aftn and then
intensifying Friday night before waning Saturday evening.
Intensifying N/NW flow will become quite strong and direct into the
terrain, with the cooling column providing a deepening DGZ into
which this ascent will maximize. Although atmospheric moisture is
modest, this flow will direct at least some Great Lakes enhanced
moisture to improve the potential for heavy upslope snowfall.
Initially, Froude numbers Friday and Friday night suggest critical=20
or blocked flow indicating the heaviest snowfall will be along or=20
just upwind of the Appalachians crests, but as flow becomes=20
unblocked on Saturday, more snow may spill over towards the east.=20
Still, the heaviest accumulations are likely in the higher terrain=20
and upwind areas, where WPC probabilities for the entire event=20
suggest a high risk (>70% chance) for at least 8" of snow, with=20
locally 12+" possible (30% chance).

The increasing W/NW flow behind the arctic front will also support
some enhanced lake effect snow (LES), especially in the favored=20
more N/NW snow belts south of Lake Ontario and Lake Superior. LES
is not expected to be extremely heavy or prolonged, but WPC
probabilities indicate a 70-90% chance for at least 4" south of=20
Lake Ontario, and a 30-50% chance across the eastern U.P. of=20
Michigan.

Finally, as a surface low strengthens well offshore and east of=20
the Mid-Atlantic states, increasing NW flow with a potential=20
inverted trough will focus some moisture and ascent across eastern=20
New England from near Portland, ME southward to Cape Cod, MA. The=20 combination of onshore flow and ocean effect snow combined with the
potential focused inverted trough may enhance snowfall along the=20
coast. The intensity of this snowfall is still quite uncertain as=20
most of it is early D3, but these inverted troughs can sometimes=20
pivot favorably for locally much heavier snowfall. Confidence is=20
modest at this time range due to wide variations in the models, but
current WPC probabilities indicate a 50-70% chance for at least 4"
of accumulation from Cape Ann southward through Cape Cod,=20
including the Boston metro area.

Finally, although not expected to be widespread, scattered snow
squalls are possible along the arctic front as it digs southward
Friday night into Saturday across the Northeast. Any convective
snow showers or squalls that develop will contain brief heavy snow
rates and strong winds, leading to hazardous travel.

Extremely cold temperatures this weekend have also prompted the
issuance of Key Messages related to this event. Those are linked
below.


Weiss


...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!9APqMvp9Avm9tP_63VeqcPXrzpjBn4ND1yCgQrSuQdPno= TECi6gsEfU5JgOPvZFmrGY8NS2tW8VKC-qRNjuSxNNPVTI$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 051918
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
218 PM EST Thu Feb 5 2026

Valid 00Z Fri Feb 06 2026 - 00Z Mon Feb 09 2026


...Great Lakes, Central Appalachians, Northeast, Mid-Atlantic...=20
Days 1-3...

A deep core low persists north of Hudson Bay through this weekend
with a focused shortwave trough plunging south from Manitoba
tonight, crossing the Great Lakes Friday, before deepening as it
pushes off the Mid-Atlantic Saturday. Rapid surface low development
is expected well east of New England on Saturday as surface high
pressure builds over the Upper Midwest, forming an intense pressure
gradient across the Northeast. A notable surge of Arctic air is
expected Friday night across the Northeast.

Extremely cold temperatures this weekend are discussed further in
Key Messages which are linked below.

The NW flow behind this shortwave will have ascent, but the
continental air and mostly ice covered Great Lakes will limit snow
rates across the Midwest. However, this NW flow will have
topographic enhancement over the central Appalachians Friday
afternoon/evening where rates will locally reach 1"/hr. The arctic
surge over this area is overnight Friday with powerful, potentially
damaging wind gusts as precip rates decrease. Day 1.5 snow probs
for >6" are 40-80% from the western edge of MD down the Allegheny
Highlands into western VA as well as the higher Apps along the
NC/TN border.

As the surface low strengthens and the whole system becomes
develops well off the Mid-Atlantic coast on Saturday, increasing=20
NW flow over an inverted trough will focus some moisture and=20
ascent across New England (outside of Maine).=20
Then on Saturday night there is potential for a focused snow band
to develop near of over Cape Cod which would have ocean
enhancements. As of now Day 2 snow probs for >4" are 40-60% for the
southern shore of Lake Ontario, along the spine of the Green Mtns,
and generally 30% over eastern Mass down through Long Island.
Values for >4" then peak around 40% over Cape Cod for Day 2.5.=20

Finally, although not expected to be widespread, scattered snow
squalls are possible along the arctic front as it digs southward
Friday night into Saturday from New York state down through central
WV. Any convective snow showers or squalls that develop will=20
contain brief heavy snow rates and strong winds, leading to=20
hazardous travel.


...Northwest...
Day 3...

Low pressure pushing northeast into the Gulf of Alaska Saturday
directs an elevated plume of moisture through the Pacific Northwest
Saturday afternoon through Sunday. Snow levels on the Cascades=20
rise to 6000 in WA and 7000ft in OR Saturday afternoon before
dropping to 5000ft in WA Sunday in moderate precip rates. Day 3
PWPF for >6" are 40-80% for the Cascade Volcanoes (above key
mountain passes) and the massif around North Cascades NP.


Jackson



...Cold Key Messages are in effect and linked below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!7KI4dATxiwGQnZk853B_9AzlywkL5ZjkFRAIwG6I2X03r= r6vHEFHnXsemfiTESuFux8NmHZX027MEkGNOGzSd9PYYDg$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 060829
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
329 AM EST Fri Feb 6 2026

Valid 12Z Fri Feb 06 2026 - 12Z Mon Feb 09 2026


...Great Lakes, Central Appalachians, Northeast, Mid-Atlantic...=20
Days 1-2...

Guidance continues to indicate a period of extreme cold will plague
the Northeast, Central Appalachians, and Mid-Atlantic states this
weekend before finally relaxing next week. For this extreme cold,
Key Messages have been issued which are linked below (Key Messages
1).

The driver of this cold will be a sharpening shortwave trough
digging across the Great Lakes today and then amplifying as it
pushes off the Mid-Atlantic coast Saturday. This should become a
closed low south of New England, with the overlap of LFQ diffluence
in a strengthening downstream jet streak with the strong height
falls at 500mb leading to a rapidly deepening surface low well
offshore. While this surface low itself will be too displaced from
the coast to bring notable weather impacts, its pressure gradient
will help enhance northerly winds across the region, driving an
arctic cold front southward, while an inverted trough pivots near
eastern New England Saturday before moving offshore. This will
result in three areas of potential heavy snowfall through Saturday.

1) Central Appalachians: the shortwave itself will cross the
Central Appalachians Friday morning into the afternoon, pushing the
strong front southeast beneath it. While some synoptic ascent into
a modestly moistening column will result in widespread light snow,
the heaviest accumulations are likely to occur within post-frontal
upslope ascent. This lift should maximize into the lower portions
of the deepening DGZ, and as moisture from the Great Lakes gets
advected southward, this will result in periods of heavy snowfall
for which the WPC prototype snowband tool suggests will exceed
1"/hr at times. The heaviest snowfall is expected Friday evening
through early Saturday morning before the column dries, and WPC
probabilities indicate a high risk (>70% chance) of at least 6
inches of snow across the higher terrain of WV, with locally 10+
inches possible, and at least 4 inches (50-70% chance) extending
from the Laurel Highlands down into the higher terrain of NC/TN.

2) Great Lakes: Although ice cover across the Lakes has increased
dramatically the past few weeks, the intense CAA behind this front
will still support some lake effect snow (LES) across the open
waters, especially south of Lake Ontario and Lake Superior D1. The
intensity of this snowfall should be somewhat muted, but WPC
probabilities for 4+ inches reach as high as 70-90% south of Lake
Ontario, with slightly lower probabilities across the eastern U.P.
and northwest L.P. of MI.

3) Eastern New England: The most challenging aspect of this
forecast is what happens across eastern New England, especially
along the coast from near Portland, ME, through Boston, MA, and
onto Cape Cod. Strong N/NE winds within the CAA should produce
ocean enhanced snowfall (OES) especially for Cape Ann and Cape Cod,
with some enhancement possible anywhere along the coast from Boston
southward. At the same time, the guidance, while very different in
its spatial positioning, all show some degree of an inverted trough
pivoting across the region, with low-level convergence aiding in
ascent. While there is uncertainty in the placement, and this
should come into better focus as we get more steadily into the
high-res windows, there is nearly uniform agreement of this
occurring, and with some fgen efficiently intersecting the lowering DGZ,
this will likely result in periods of heavy snowfall. Despite the=20 uncertainty, WPC probabilities have crept upwards to above 50% for
4+ inches from near Portsmouth, NH south to Boston and Plymouth,
MA,but some locally higher amounts are probable as reflected by a=20
lot of spread in the WSE plumes for coastal areas.

Finally, although not expected to be widespread, scattered snow=20
squalls are possible along the arctic front as it digs southward=20
Friday night into Saturday from New York state down through central
WV and into New England. Any convective snow showers or squalls=20
that develop will contain brief heavy snow rates and strong winds,=20
leading to hazardous travel.


...Pacific Northwest and Northern Rockies...=20
Day 3...

A shortwave emerging from the Northern Pacific will track eastward,
moving onshore WA/OR Sunday night and then deamplifying as it
approaches the Northern Rockies by the end of the forecast period.
Downstream of this impulse, a period of enhanced moisture advection
will occur, both in response to modest WAA as well as a weak upper
jet streak pivoting into Canada. Together, this will drive IVT
onshore in a corridor from OR through the Northern Rockies, which
has a high probabilities (>80%) of exceeding 250 kg/m/s. The
duration of this IVT is likely to be limited, and the corresponding
WAA will surge snow levels up to 5000-6000 ft before falling the
latter half of D3 (due to CAA behind an accompanying cold front)
back down to 2000-3000 ft. However, most of the precipitation
should occur within the warm plume, and this is reflected by WPC
probabilities indicating a high risk (>70% chance) for at least 4
inches of snow for the higher terrain of the Cascades and into=20
parts of the Northern Rockies near Glacier NP, and into the=20
Sawtooth/Salmon River ranges.

Weiss



...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!7nWiQeLPwPN72vtw9t41hN6JrVIti4KCD6SQD2TX7WWPP= ZZgrW4eB3_Vk4vl1tNvlEpBd3HXuZLoyLL7HuFiyW4fumA$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 061933
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
233 PM EST Fri Feb 6 2026

Valid 00Z Sat Feb 07 2026 - 00Z Tue Feb 10 2026


...Great Lakes, Central Appalachians, Northeast, Mid-Atlantic...=20
Days 1-2...

Extreme cold and dangerous wind chills overspreads the Northeast=20
tonight with Key Messages in effect and linked below.

An upper low currently over James Bay gets sheared southeast over
the Northeast tonight on account of a strengthening NWly jet below
a stationary parent low north of Hudson Bay. Surface low pressure
develops early Saturday outside of the 70W/40N Benchmark with an
inverted trough extending from that low up through eastern New=20
England. This movement results in three notable areas of snow.

1) Central/Southern Appalachians: Ongoing upslope snow for the=20 central/southern Apps through this evening with powerful winds
overnight behind the cold front. Not much additional snow is
expected, particularly due to the Great Lakes being mostly ice=20
covered, but blowing snow is certainly a concern.

2) Great Lakes: Spotty lake effect snow will continue into Saturday
for parts of northern MI downwind of open portions of Lake=20
Superior and Michigan.

3) Eastern New England: Strong N/NE winds within the CAA should=20
produce ocean enhanced snowfall (OES) in eastern Mass. At the same
time, the inverted trough pivots across the region with low- level
convergence aiding in ascent. Fgen efficiently intersecting the=20
lowering DGZ will result in narrow corridors of heavy snowfall.=20
Day 1 snow probs for >4" are 40-70% for southern NH down through
Rhode Island.

Snow Squalls: the greatest snow squall threat is this evening over
Ohio and West Virginia west of the Allegheny Front where high=20
winds coincide with frontal banding. This area has had the most=20
notable snow squall parameter values in recent days. Any convective
snow showers or squalls that develop will contain brief heavy snow
rates and strong winds, leading to hazardous travel.
More general snowfall can be expected with the front tonight across
NY state and the Green Mtns.=20


...Pacific Northwest and Northern Rockies...=20
Days 1-3...

A shortwave trough axis crosses the Pacific Northwest Saturday/=20
Saturday night with a second trough crossing late Sunday into
Monday. Enhanced moisture advection spreads inland ahead of these
waves with increasing snow over the Cascades and Northern Rockies.=20=20
Snow levels rise to 6000/7000ft tonight for the WA/OR Cascades with
levels over WA dropping up to 4000ft Saturday night under height
falls. Day 1 snow probs for >4" are 40-70% for the North Cascades
and WA Volcanoes above 6000ft. Day 2 snow probs for >6" are 40-70%
for the higher WA/OR Cascades and the highest northwest MT ranges.
Much of the Northwest gets moderate precip with the second wave,
Day 3 snow probs for >6" are 50-80% for the WA/OR Cascades above
4000ft and across western MT/central and northern ID and northwest
WY ranges.


Jackson



...Cold Key Messages are in effect and linked below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!6KUdSlc3x9gxIvJgJ8CClYrdLr-MkgN3h8WhznNitWZ-i= rLKGoqcAEia_Z2pz_5BOuh2Xqg3C0gJPFrlj7Ux-nuxS00$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 070706
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
206 AM EST Sat Feb 7 2026

Valid 12Z Sat Feb 07 2026 - 12Z Tue Feb 10 2026


...Northeast & Mid-Atlantic...=20
Day 1...

Extreme cold and dangerous wind chills overspread the Northeast=20
tonight and continue through Sunday with Key Messages in effect=20
and linked below.

The combination of an arctic cold front current racing through the
Ohio Valley/Interior Mid-Atlantic will combine with a strengthening
low pressure well offshore to produce extremely cold temperatures
and damaging winds for much of the region, with heavy snow for=20
parts of the area as well.

A shortwave driving the cold front southward will help generate
widespread light snow across New England and Long Island, but total
snowfall amounts are expected to be rather modest. Despite that,
briefly heavy snow rates combined with the rapidly increasing winds
will still result in impacts, especially to travel due to snow-
covered roads and low visibility. The greatest impacts, and likely
more substantial snowfall, is expected from far SW Maine, SE New
Hampshire, and along the eastern Coast of Massachusetts from Cape
Ann to Cape Cod where low-level convergence, onshore flow and
resulting ocean effect snow (OES) and an inverted trough will all
interact to enhance snowfall. There continues to be uncertainty as
to where the heaviest snowfall will occur. However, intense=20
snowfall rates of 1-2"/hr are possible (30-60% chance) thanks to=20
intense ascent into a lowering DGZ within the presence of some=20
instability. WPC probabilities are moderate (50-70%) for 4+ inches=20
from the Seacoast of NH through the Boston metro area, with locally
more than 8 inches possible (10-30% chance) and as reflected by=20
significant spread amongst the WSE plumes.


...Pacific Northwest and Northern Rockies...=20
Days 1-3...

Mid-level trough positioned off the Pacific coast will slowly track
eastward today and Sunday, with the primary trough axis finally
pushing onshore Sunday night as a shortwave lifts onshore near the
CA/OR coast. This shortwave will then continue to track east while deamplifying, reaching the northern High Plains by the end of the
forecast period.

This trough evolution will be accompanied by a modest subtropical
jet streak arcing meridionally downstream to provide overlapping
synoptic ascent. This lift will occur into a moistening column as
persistent SW flow ahead of the shortwave/trough axis will provide
a long duration of IVT exceeding 250 kg/m/s, with IVT max
potentially exceeding 500 kg/m/s (50-60% chance) which will lead to
two rounds of heavy precipitation extending from Oregon through=20
the Northern Rockies. Snow levels within the strongest IVT plume
will be 6000-7000 ft thanks to pronounced WAA, but will steadily
fall to 3000-4000 ft Monday as a cold front, driven by the
aforementioned trough, progresses southeast. This will allow for
heavier and more impactful snow across the Northern Rockies than
what is anticipated in the Cascades due to lower snow levels. 2-day
WPC probabilities indicate the heaviest snow is expected in the
vicinity of Glacier NP in the Northern Rockies where they exceed
70% for 12+ inches, and locally as much as 2 feet is possible in
the highest terrain. Elsewhere, WPC probabilities are high (>70%)
for 8+ inches across the Absarokas and Tetons near Yellowstone NP,
the Blue Mountains of OR, and across the highest peaks of the WA=20
and OR Cascades.



Weiss


...Extreme Cold Key Messages are in effect. Please see current Key
Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!4Xa2oHMmm6KfYz7unG9Agh0MhfUQ7fqpY9sRHyH0zmenP= 8OIT453zr1s2_i_RtderGizZjFyR5DPVZVOSXZzX8SPp3g$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 071904
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
204 PM EST Sat Feb 7 2026

Valid 00Z Sun Feb 08 2026 - 00Z Wed Feb 11 2026


...Southeast New England...=20
Day 1...

Ongoing convergent banding over southeast New England will continue
to shunt east as it gets further undercut by the Arctic cold front
which will shift offshore late evening. Remaining snow should taper
off this evening.


...Pacific Northwest and Northern Rockies...=20
Days 1-2...

A trough axis pushes across western WA this evening with the
leading moisture axis maintaining moderate precip rates until the
overnight when they are shunted south. Snow levels on the WA
Cascades decrease from 6000ft to 4000ft tonight under height falls.=20
The primary trough axis pushes onshore the PacNW Sunday evening. This
wave will then continue to track east while deamplifying, reaching
the northern High Plains Monday.

This trough evolution will be accompanied by a modest subtropical
jet streak arcing meridionally downstream to provide overlapping
synoptic ascent. This lift will occur into a moistening column as
persistent SW flow ahead of the shortwave/trough axis will provide
a long duration of moisture advection with two rounds of heavy=20
precipitation extending from Oregon through the Northern Rockies.=20
Day 1 snow probs for >6" are 40-80% for the WA/OR Cascades above
about 5000ft and over the northern Rockies. Day 2 snow probs for

6" are similar to Day 1 for the Cascades, but much greater across

the northern Rockies including 50-90% for the Tetons, Absarokas,
Sawtooths, Bitterroots, and through Glacier NP. Snow tapers off
Monday as the trough axis shifts onto the Plains.


...Sierra Nevada and Great Basin...=20
Day 3...

The next shortwave trough from the Pacific shifts farther south
than more recent ones, reaching the central/northern CA coast late
Monday night, crossing the Great Basin Tuesday night. Snow levels
of 6000 to 7000ft can be expected on the Sierra Nevada with the
early snow Monday night and 5000 to 6000ft Tuesday as the trough
axis approaches. Day 3 snow probs for >6" are 50-80% over the
length of the Sierra Nevada. A welcome sight for skiers and those
with Sierra hydrology interests.


Jackson



...Extreme Cold Key Messages are in effect and linked below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!-BeRRGW9T0baCl--AvirbLAP2kstK75nNVKBxmBURQ_C9= uocuM5i-gTcobPUFZa9ROYAvgzvZ3UZTtfsdeDhIKBI4LY$=20


$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 080719
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
219 AM EST Sun Feb 8 2026

Valid 12Z Sun Feb 08 2026 - 12Z Wed Feb 11 2026


...Pacific Northwest and Northern Rockies...=20
Days 1-2...

A surface cold front will be draped NE to SW from Montana through
Oregon to start the period, lingering from a wave of low pressure
moving across Canada. As this cold front wavers Sunday, a
shortwave trough will emerge from the Pacific and cross northeast
into the Pacific Northwest, reaching the Northern Rockies Monday
evening while deamplifying and shearing out into the westerlies.
This will result in a secondary wave of low pressure developing
along the front which will finally kick the front southeast and out
of the region.

Forcing for ascent will intensify as this shortwave lifts
northeast, as mid-level divergence and heights falls interact atop
the boundary, and work in tandem with a zonally oriented but
intensifying jet streak arcing into the Northern Plains. This
synoptic lift atop the corresponding moisture (via strengthening
but still modest IVT) will result in a stripe of precipitation,
with snowfall expected in the higher terrain. Snow levels will be
falling through the period as the cold front and height falls
progress E/SE, reaching as low as 3000-4000 ft before precip winds
down by Tuesday morning. 2-day WPC probabilities indicate a high
potential (>70% chance) for at least 8 inches in the higher terrain
of the Cascades, as well as across the Blue Mountains, and much of
the terrain of the Northern Rockies of ID/western MT/northwest WY.
Locally 1-2 feet is possible.


...Sierra Nevada and Great Basin...=20
Days 2-3...

A closed mid-level low west of California will gradually translate
eastward, potentially coming onshore northern California by the end
of the forecast period. The progression of this low will result in
increasing ascent through height falls/mid-level divergence into
CA. At the same time, a subtropical jet streak will intensify
downstream of this trough axis, strengthening to 130 kts and
placing the favorable LFQ diffluent region over CA and into the
Great Basin, aligning with the strongest height falls. Moisture
advection will spread onshore beneath modest IVT (40-60% chance of
at least 250 kg/m/s) but this will be sufficient to spread heavy
precipitation into the region. With snow levels expected to be
generally 6000-7000 ft, the heavy snow should be confined to the
Sierra and higher terrain farther east (Ruby mountains of NV and
into the Uintas, but at least light snow will spread across much of
the Great Basin above 6000 ft, rare for what has been an
exceptionally dry winter so far, and likely welcome for most of the
region. Current WPC probabilities indicate a high chance (>70%) for
more than 8 inches in the high Sierra, with locally more than 12
inches possible (30-50% chance). Farther east, WPC probabilities
indicate a low risk (30%) for 6+ inches in the Ruby Mountains and
parts of the Uintas.


...Northeast...
Day 3...

A clipper-type low will drop out of Ontario and cross Upstate New
York and New England Tuesday evening/Tuesday night. The clipper
itself is not impressively strong, but will be preceded by a period
of moderate WAA which will help expand a shield of snowfall with
moderate snow rates from NY through central/northern New England.
As the clipper dives through the area after 00Z Wednesday, it will
be followed additionally by some upslope ascent into the
Adirondacks and Greens to enhance snowfall potential. Most of the
snow should be of moderate intensity and limited duration (6-12
hours), but where the WAA snow combined with post-system upslope
snow, a few inches of accumulation is likely. This is reflected by
WPC probabilities that indicate a 50-70% chance of at least 4
inches in the Adirondacks and Greens.


Weiss



...Extreme Cold Key Messages are in effect. Please see current Key
Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!8eF8W36sZqTxakcMe0UhPFhNgT5PYu0eE845MF0JBX84Q= a-TSjewl7qNUuyG1gEbVE4ah4GKia6xdYgvnsASn-AS6ng$=20



$$

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 082034
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
334 PM EST Sun Feb 8 2026

Valid 00Z Mon Feb 09 2026 - 00Z Thu Feb 12 2026


...Pacific Northwest through Northern Rockies...
Day 1...

A shortwave trough crosses the Pacific Northwest this evening and
the northern Rockies Monday. Much of the moisture is ahead of this
trough axis with moderate to heavy rates stretches from far
northern CA through OR and western MT. Snow levels are initially
high, around 7000ft, over northern CA through ID/southern
MT, with a gradient down to 4000ft just a couple hundred miles
north. Height falls from the trough axis will lower tonight to
around 4000ft across the snow zone (3000ft where the 4000ft levels
currently are). Day 1 snow probs are 50-80% for >6" across the
Sawtooths through Bitterroots, and all western MT and northwest WY
ranges. These values are generally 30-70% for the WA/OR Cascades
above about 5000ft. Ridging behind the trough axis will provide a
fairly clean cut off for this mountain snow fall by late Monday.


...Sierra Nevada to Wyoming...
Days 2-3...

A closed mid-level low will approach central California from the
west on Tuesday before stalling over northern CA through much of
Wednesday as a reinforcing trough digs around it well offshore.
Strengthening left exit jet dynamics through this time will enhance
lift for the onshore flow that rises over the Sierra Nevada. Energy
sheds east from the upper low Tuesday night bringing much needed
precip to the Great Basin and central Rockies through midweek.

Snow levels will be at or just below 7000ft along the Sierra Nevada
on Tuesday in the onshore flow, dropping to around 6000ft Tuesday
night under height falls. Great Basin/Rockies snow levels will
generally remain 6000-7000ft through midweek.

Day 2 snow probs for >6" are generally 30-60% along the Sierra
Nevada (and Lassen Peak) for the initial snow on Tuesday. The bulk
of Sierra snow falls Tuesday night/Wednesday with Day 3 snow probs
for >12" generally 30-60% between 6500ft and 8000ft (and 80%
above). High-end advisories are raised for the Sierra Nevada. There
is risk for localized enhanced snowfall that would warrant targeted
warnings, particularly if rates can pick up around 7000ft
elevation. Farther east, Day 3 snow probs for >6" are 30-70% on the
highest NV ranges (such as Ruby), the highest Uinta, and
particularly for the Tetons and Wind Rivers.


...Northern Great Lakes and Northeast...
Days 2/3...

The shortwave trough crossing the Pacific Northwest tonight reaches
the northern Great Lakes Monday night where it could merge with
northern stream energy over Ontario and promote decent
development/warm air advection precip over the northern Great
Lakes. This would be a wintry mix on the southern end with some
snow banding potential either over Lake Superior or possibly into
the eastern U.P. Day 2 snow probs for >4" are 20-50% over the far
northern L.P. and eastern U.P. while there are 40-70% probs for

0.01" ice from the WI/MI border ESE across the L.P.

By Tuesday afternoon the warm air advection plume shifts through
Upstate NY with the warm nose great enough for a wintry mix which
should tend toward freezing rain given how cold it has been there
lately. Day 2.5 snow probs for >4" are 30-70% over the Tug Hill,
Adirondacks, and Greens while 0.01" ice probs are 30 to 50% for
northern PA through southern NY and east through greater NYC.

Coastal low development aids snow banding into eastern Maine on
Tuesday night into Wednesday. Day 3 snow probs for >4" are 30-50%
along the entire Maine Coast.


Jackson



$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 090734
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
234 AM EST Mon Feb 9 2026

Valid 12Z Mon Feb 09 2026 - 12Z Thu Feb 12 2026


...Pacific Northwest through Northern Rockies...
Day 1...

A shortwave trough crossing the area will be positioned atop the
interior Northwest to start the period, and then translate rapidly
eastward through D1. This feature will likely shear out into the
westerlies as it advects into the High Plains in response to rapid
ridging building in its wake, but there has been a subtle trend of
increased amplitude of this feature tonight. This shortwave will
work effectively with an intensifying upper jet streak to overlap
mid-level height falls with LFQ diffluence, leading to sufficient
ascent to produce a wave of low pressure along a cold front south
of the region.

Additionally, this jet streak will result in increasing mid-level frontogenesis, especially within the 700-500mb layer, which will
produce impressive omega directly into the DGZ. Although ascent
will be temporally modest, cross-sections indicate a high threat
for CSI within any snow bands that develop, and this could (30-60%
chance) produce 1-2"/hr snowfall rates. The heaviest snowfall is
likely in the terrain of the Absarokas and near Yellowstone NP due
to upslope enhancement, but anywhere across southern MT and
northern WY could see bands of heavy snowfall which will accumulate
rapidly despite marginal thermals in the low- levels. The high-res
guidance has trended upward significantly, as have many of the
globals, so confidence has increased in significant snowfall
accumulations, which is now reflected by WPC probabilities that
indicate a high risk (>70% chance) for at least 4 inches, with more
than 12 inches possible in the higher terrain including the Lewis
Range and Tetons.


...Sierra Nevada to the Central Rockies...
Days 2-3...

A closed mid-level low will approach central California from the
west on Tuesday before slowly filling into an open, positively
tilted trough Wednesday as secondary vorticity energy digs towards
Baja. This slow evolution will result in pronounced S/SW flow
aloft, which will combine with a strengthening jet streak to spread
moisture onshore CA and then expand eastward towards the Central
Rockies by late Wednesday. This prolonged, albeit relatively
modest, moisture plume/IVT will bring much needed precip to the
Great Basin and central Rockies through midweek.

Snow levels will be at or just below 7000ft along the Sierra Nevada
on Tuesday in the onshore flow, dropping to around 6000ft Tuesday
night under height falls. Great Basin/Rockies snow levels will
generally remain 6000-7000ft through midweek.

2-day snow probabilities from WPC suggest a near certainty (>90%)
of at least 8 inches across much of the Sierra with locally as much
as 2 feet possible (30% chance) in the higher Sierra. Additional
snowfall totals exceeding 8 inches are possible (50-70%) for parts
of the Uintas, Colorado Rockies, and northern CA ranges.


...Northern Great Lakes and Northeast...
Days 1-3...

A closed mid-level low will elongate and track from the Northern
Great Lakes to across New England mid-week, exiting to the Gulf of
Maine by Thursday morning. This upper feature will be accompanied
by an extended vorticity lobe on its south side, helping to produce
strong ascent through height falls/PVA across the region. As this
develops, pronounced warm air advection (WAA) will develop to its
south as a surface low /clipper type/ races southeast beneath the
upper trough. This will produce two rounds of ascent: first with
the intensifying WAA south of the surface low, and then second with post-clipper CAA/upslope flow.

While the ascent within the WAA will be impressive, it will also be
of short duration, generally 6-12 hours, so although snowfall rates
will likely be intense (50-70% chance of 1+"/hr), the total
snowfall accumulations will be tempered as reflected by WPC
probabilities that are around 30% for 4+ inches across the U.P. of
MI D1, and then 30-70% on D2 for Upstate NY and northern/central
New England. Despite that, some more significant snowfall
accumulations are likely across the Tug Hill Plateau, the
Adirondacks, and the Greens where a combination of CAA for lake
effect snow (in the Tug Hill) and upslope snow (Adirondacks and
Greens) will lengthen the duration of accumulating snowfall. In
these areas, locally more than 8 inches of snow is possible
(10-30%, highest across the Tug Hill Plateau).

Finally, as the closed low moves into the Gulf of Maine, a surface
low will deepen offshore in response. While direct impacts from
this surface low are not expected to be significant, the guidance
is hinting at a lingering inverted trough pivoting back across
coastal Maine Wednesday. These inverted troughs can sometimes lead
to sneaky-heavy snowfall accumulations, so although current WPC
probabilities are around 50-70% for 4+ inches of snow, this will
need to be monitored for any upticks as the event gets closer.


Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 091952
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
252 PM EST Mon Feb 9 2026

Valid 00Z Tue Feb 10 2026 - 00Z Fri Feb 13 2026


...Sierra Nevada to the Central Rockies...
Days 1-3...

A mid-level low in the northeast Pacific just north of a 150kt jet
streak this evening will move southeastward then eastward into
NorCal tomorrow night. This will direct a modest plume of moisture
into the Sierra with snow levels initially around 7000ft then
dropping to around 6000ft. Snow could fall at >1"/hr tomorrow night
in the higher Sierra (>8000ft) then subside through Wednesday. WPC probabilities for at least 8 inches of snow are >50% above 6000ft
or so with >18" likely (<80%) above 8000ft.

The system will continue eastward as the upper jet strengthens
over the Great Basin to central Rockies as the upper trough remains positively-tilted. Moisture will continue to funnel from the sub-
tropics into the Four Corners region (>90th percentile) on
southwesterly flow. Snow levels will waver around 6000-7000ft with
modest amounts expected in an area that has seen very little snow
this season. WPC probabilities for at least 8 inches of snow are

50% above 7000ft or so in UT and 8000ft in WY. Snow will linger

longest over the CO Rockies through Thursday as the moisture plume
stalls there as a result of a second shortwave trailing the lead
system, maintaining SW flow through the end of this period. WPC
probabilities for at least 8 inches of snow are >50% above 10,000ft
or so in CO.


...Northern Great Lakes and Northeast...
Days 1-3...

A progressive closed mid-level low will elongate and track from
the Northern Great Lakes to across New England mid-week,
translating into the Gulf of Maine on Wednesday. This upper feature
will be accompanied by an extended vorticity lobe on its south
side along the occlusion, helping to produce strong ascent through
height falls/PVA across the region. As this develops, pronounced
warm air advection (WAA) will develop to its south up and over a
surface warm front across the Mid-Atlantic. Lead WAA- drive
precipitation will arrive over northern NY/New England tomorrow
evening followed by the frontal passage. CAA will ensue with some
lake effect and upslope snow across the region Wednesday through
Thursday.

Quasi-zonal flow will limit precipitation duration, but CAM
guidance still indicates a window of >1"/hr rates (50-80% chance)
over the Adirondacks, northern and central VT/NH, and into
southwest Maine between 21Z Tue and 04Z Wed (from west to east)
ahead of the occlusion and as it translates into the Gulf of Maine.
Behind the front, NW flow will support widespread multi-banded
lake effect snow downwind of all Great Lakes (less from mostly all-
frozen Erie) that will be enhanced at times from trailing vort
maxes streaming in from the NW.

WPC probabilities for at least 4 inches of snow for the event are

50% over southwestern NY, central NY into the Adirondacks/North

Country, northern VT/NH and across much of Maine except for far
northern areas (removed from the higher QPF). Some favored upslope
areas could see in excess of 8 inches of snow, especially over the
Tug Hill into the Green Mountains.

Finally, as the closed low moves into the Gulf of Maine, a new
surface low down the occlusion will deepen offshore in response.
While direct impacts from this surface low are not expected to be
significant, the guidance (e.g., NAMnest, CMCreg) is hinting at a
lingering inverted trough pivoting back across coastal Maine
Wednesday afternoon/evening. These inverted troughs can sometimes
lead to sneaky-heavy snowfall accumulations. WPC probabilities for
at least 8 inches of snow between Bangor and Eastport are 25-45%
right now, and may change pending more hi-res guidance.


Fracasso/Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 100716
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
216 AM EST Tue Feb 10 2026

Valid 12Z Tue Feb 10 2026 - 12Z Fri Feb 13 2026


...Sierra Nevada to the Central Rockies...
Days 1-3...

Mid-level low over the Pacific will gradually pivot eastward
towards northern CA through Wednesday, lingering across the state
as it slowly fills. Immediately downstream of this feature, a
subtropical jet streak will intensify, especially late this evening
into Wednesday morning, reaching towards 150 kts as it pivots over
central CA. This upper jet will provide favorable LFQ diffluence
overlapping the most significant height falls for pronounced
synoptic ascent, while additionally transporting Pacific moisture
onshore CA before spreading into the Great Basin and Central
Rockies. The evolution of this synoptic pattern suggests that SW
flow downstream of the primary trough axis will support prolonged
moisture advection, which is reflected by IVT probabilities from
both the GEFS and ECENS exceeding 90% for 250 kg/m/s for around 24
today into Wednesday. This moisture will be wrung out by the
significant deep layer ascent (aided by upslope flow especially
across the Sierra) to produce heavy snowfall above generally
6000-7000 ft, with the most intense snowfall rates (2+"/hr
according to the WPC prototype snowband tool) occurring across the
Sierra tonight into Wednesday. WPC probabilities across the Sierra
are high (>70%, 2-day totals) for more than 12 inches in the high
SIerra, but widespread 8+ inches is likely (>70%) for the breadth
of the Sierra and into parts of the northern California terrain.

As the system continues eastward and the upper jet strengthens
over the Great Basin to central Rockies, moisture will continue to
funnel from the sub-tropics into the Four Corners region on
southwesterly flow. Snow levels will waver around 6000-7000ft with
modest amounts expected in an area that has seen very little snow
this season. WPC probabilities for at least 8 inches of snow are

50% above 7000ft or so in UT and 8000ft in WY, highest over the

Uintas and Wind Rivers/Tetons. Snow will linger longest over the
CO Rockies through Thursday as the moisture plume stalls there as a
result of a second shortwave trailing the lead system, maintaining
SW flow through the end of this period. WPC probabilities for at
least 8 inches are high for 8+ inches across much of the highest
terrain of the Colorado Rockies, with a local maximum above 12
inches expected across the Park Range.


...Eastern Great Lakes and Northeast...
Days 1-2...

A clipper-type low will dig southeast from Ontario through New
England today, exiting into the Gulf of Maine late tonight. This
clipper will be driven primarily by a closed, but weakening, mid-
level low tracking atop it, with elongated vorticity to its south
producing additional ascent. As this upper low shifts off New
England, it will interact with an occlusion well off the coast,
helping to rapidly deepen a surface low over the Atlantic. This
synoptic evolution will result in 3 areas of moderate to heavy
snowfall:

1) Pronounced warm-air-advection (WAA) developing south of the
clipper will surge northeast atop a warm front across the Mid-
Atlantic and into the Northeast. This will create an expanding
shield of precipitation, and although some light mixed
rain/snow/freezing rain is expected over the northern Mid-Atlantic,
much of this precipitation should fall as snow across New England
and Upstate New York. The snow that occurs will likely be heavy at
times within a WAA band, likely exceeding 1"/hr (60-90% chance),
with the short temporal duration limiting the total snowfall.
Still, impactful snow is likely this evening and tonight spreading
from west to east.

2) Post-clipper cold-air-advection (CAA) will become impressive in
the wake of the low. This will create increasing lake effect snow
(LES) despite significant ice cover now over the Great Lakes, as
well as intensifying upslope snow into the terrain of the
Adirondacks and Greens. Very dry air beneath the subsidence
inversion will impinge into the DGZ from above during this time, so
that will act to limit snowfall intensity within the upslope
regime, but additional accumulations are likely. LES will also be
somewhat modest, and focused east of Lake Ontario into the Tug Hill
and then southeast towards the Finger Lakes region, as well as far
SW NY east of Lake Erie.

WPC probabilities for 2+ inches of snow are high (>70%) for much
of northern Upstate NY, as well as central/northern New England.
However, the more substantial snowfall is likely in the higher
elevations where WPC probabilities suggest a high risk (>70%) for
at least 4 inches in the Adirondacks, Greens, and Whites, with
locally as much as 8 inches possible. For the LES areas, WPC
probabilities are moderate (50-70%) for least 4 inches. For the
freezing rain, a swath of moderate probabilities (>50%) exists for
0.01+" of ice from the Finger Lakes through the Poconos and into
southern New England and Long Island. Although amounts should be
less than 0.1"

3) Finally, as the surface low deepens rapidly offshore and near
Nova Scotia Wednesday, the guidance continues to suggest a
lingering inverted trough will pivot near the coast of Maine. Where
this occurs, additional ascent will be locally impressive, leading
to the potential for several inches of additional snowfall. These
inverted troughs can sometimes lead to sneaky-heavy snowfall
accumulations, so while WPC probabilities are moderate for 6+
inches (50-70%), locally higher totals are possible as reflected by
significant spread in the WSE plumes along the coast of Maine.

Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 101945
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
245 PM EST Tue Feb 10 2026

Valid 00Z Wed Feb 11 2026 - 00Z Sat Feb 14 2026


...Sierra Nevada to the Central/Southern Rockies...
Days 1-3...

Closed low just west of NorCal will push eastward tonight as a
surface cold front moves toward/into the Sierra. A trailing upper
low to its northwest will take a longer route along its southwest
side and eventually move into the Southwest/northeastern Mexico
late in the forecast period. The trough axis will remain
positively-tilted as the two entities act to slow the overall
progress of the flow resulting in an unsettled period but bounded
by two periods of modest to perhaps heavier precipitation. Moisture
amounts and flux anomalies are modest, but accumulations will be
aided by favorable upslope SW flow. Snow levels will vary between
6000-7000ft over the Sierra and snow rates will likely be >1-2"/hr
at times tonight/early Wednesday per the 12Z CAM guidance. WPC
probabilities for at least 12 inches of snow are >50% above 6500ft
or so. Two-day totals may exceed 2ft in the highest elevations.

Farther downstream, moisture tied back to the subtropics will
continue to increase over the Great Basin to the central Rockies
tonight as the upper jet accelerates over the region and PVA
increases. Snow levels around 6000-7000ft will favor mountain snow
to areas that have seen very little this season. WPC probabilities
for at least 8 inches of snow are >50% above 7000ft or so in UT and
8000ft in WY, highest over the Uintas and Wind Rivers/Tetons, but
with modest totals overall. Snow will linger longest over the CO
Rockies through Thursday as the moisture plume stalls due to the
trailing upper low. WPC probabilities for at least 8 inches of snow
are >70% above 10,000ft or so in CO. By Friday, as that system
finally moves over northeastern Mexico, moisture and height falls
will lead to snow over the southern Rockies (southwestern CO and
northern NM) as well as into AZ (Mogollon Rim/White Mountains).
Amounts will be light except for the highest elevations, generally
above 10,000ft.


...Eastern Great Lakes and Northeast...
Days 1-2...

A strong clipper-type low will move through New England tonight
and stretch out to the Gulf of Maine by tomorrow morning. This
clipper will be driven primarily by a closed, but weakening, mid-
level low tracking atop it, with elongated vorticity to its south
producing additional ascent. The elongated vorticity will favor a
jump in the surface low down the occlusion and into the Gulf of
Maine by 12Z Wed which will then start to rapidly deepen as it
pulls away into Atlantic Canada. The storm will come in three
distinct parts related to winter weather:

1) Pronounced warm-air-advection (WAA) developing south of the
clipper this evening will surge northeastward atop a warm front
across the Mid-Atlantic and into the Northeast. This will create an
expanding shield of precipitation, and although some light mixed rain/snow/freezing rain is expected over the northern Mid- Atlantic
into the NYC metro area, much of this precipitation should fall as
snow across New England (esp north of I-90) and Upstate New York.
The snow that occurs will likely be heavy at times within a WAA
band, likely exceeding 1"/hr (60-90% chance per the 12Z HREF), with
the short temporal duration limiting the total snowfall. Still,
impactful snow is likely this evening and tonight spreading from
west to east with the highest totals over the Adirondacks and
central/northern New England.

2) Post-clipper cold-air-advection (CAA) will become impressive in
the wake of the low. This will create increasing lake effect snow
(LES) despite significant ice cover now over the Great Lakes, as
well as intensifying upslope snow into the terrain of the
Adirondacks and Greens. Very dry air beneath the subsidence
inversion will impinge into the DGZ from above during this time, so
that will act to limit snowfall intensity within the upslope
regime, but additional accumulations are likely. LES will also be
somewhat modest and multi-banded, focused east of Lake Ontario into
the Tug Hill and then southeast through the Finger Lakes region
into far SW NY east of mostly frozen Lake Erie (likely aided from
Lake Huron and/or Georgian Bay).

WPC probabilities for at least 4 inches of snow are >50% for the
western Adirondacks as well as central/northern New England and
much of Maine, especially outside the lower elevations. For the
higher elevations, WPC probabilities for at least 6 inches of snow
are >50% over the Greens, Whites, and the Central Highlands in
Maine with locally as much as 8 inches possible. For the LES areas
in NY, WPC probabilities are moderate (40-70%) for least 4 inches
with higher local accumulations. For the freezing rain, a swath of
moderate probabilities (40-70%) exists for 0.01+" of ice from the
Finger Lakes/Southern Tier down I-88/81 through the Poconos
eastward along I-80 through northern NJ and into southern New
England and perhaps Long Island. Amounts should be less than 0.10"
but any freezing rain can be hazardous to travel, especially
overnight.

3) Finally, as the surface low deepens rapidly offshore and near
Nova Scotia Wednesday, the guidance continues to suggest a
lingering inverted trough that will pivot near the coast of eastern
Maine. Where this occurs, additional ascent will be locally
impressive, leading to the potential for several inches of
additional snowfall. These inverted troughs can sometimes lead to
sneaky-heavy snowfall accumulations, but WPC probabilities for at
least 8 inches of snow are moderate (40-70%) around Eastport.
Locally higher totals are possible as reflected in some rather
robust 12Z CAM members along the coast of Maine.

The probability of significant icing across the CONUS is less than
10 percent.


Fracasso/Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 110625
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
125 AM EST Wed Feb 11 2026

Valid 12Z Wed Feb 11 2026 - 12Z Sat Feb 14 2026

...Eastern Great Lakes and Northeast...
Day 1...

The strong clipper-type low will continue to push east off the New
England coast as the driving shortwave aloft races to the
southeast. The vorticity accompanying this shortwave will help
develop secondary low pressure along a triple point well offshore
(near Nova Scotia), with this secondary low deepening as it pulls
away. Although this low should be well too far east to bring any
direct impacts to the Northeast, the guidance continues to indicate
an inverted trough will pivot cyclonically around the low, bringing
enhanced ascent to the coast of Maine, resulting in bands of heavy
snow. Some uncertainty continues with the exact placement of these
bands, but the high-res is quite agreeable in their occurrence.
This suggests that while WPC probabilities for 4+ inches are just
30-50% across primarily the Downeast coast of Maine, some locally
higher totals are probable as reflected by pronounced spread in the
WSE plumes.

Additionally, in the wake of this clipper, increasing CAA
atop the Great Lakes, despite significant ice cover, will result in
periods of lake effect snow, primarily E/SE of Lake Ontario with
some lighter snowfall east of Lake Erie which is mostly ice
covered. WPC probabilities for this LES are high (>70%) for 4+
inches for the western Adirondacks, Tug Hill Plateau, Finger Lakes
region, and northern Chautauqua Ridge. The greatest accumulations,
which may exceed 8 inches (30% chance) are across the Tug Hill.


...Sierra Nevada to the Central/Southern Rockies...
Days 1-2...

A closed mid-level low positioned along the coast of northern CA
will generally fill in place as the accompanying longwave trough
elongates back to the southwest as secondary vorticity energy
rotates through the base ot approach southern CA and Baja by Friday
morning. This stalled evolution will result in a resurgence of an
upper level jet streak to sharpen downstream of this trough axis,
and while the secondary jet streak tonight into Thursday won't be
as powerful as the lead jet, it will maintain moisture advection
and broad LFQ diffluent ascent from CA into the Central Rockies.
The overlap of this jet streak with broad but persistent SW mid-
level flow also downstream of the primary trough axis will surge
moisture eastward as far as CO as reflected by NAEFS IVT
percentiles surging to above the 99th percentile in CO, with
prolonged anomalies above the 90th percentile back into the Great
Basin.

This plume of moisture will be primarily shed eastward within a WAA
plume, so snow levels will be generally 6000-7000 ft, lowering
slowly as the trough axis pivots eastward, but this will likely be
accompanied by rapid drying and a resulting cutoff of
precipitation. For this reason, the heaviest snowfall accumulations
are likely to be above 7000 ft (as high as 8000 ft in CO), with a
wane in precipitation expected as snow levels fall. WPC
probabilities D1 are high for at least 6 inches of snow in the high
Sierra, the Uintas/Wasatch, the Tetons/Wind Rivers, and parts of
the CO Rockies including the Park Range. D2 probabilities compress
and fall rapidly, leading to just residual elevated probabilities
above 30% for 4+ inches in the CO Rockies.


...Southern Rockies...
Day 3...

The same secondary shortwave responsible for elongating the trough
over CA/Great Basin D2 will shed eastward Friday morning, moving
across southern CA/Baja Norte before closing off once again near
the Four Corners Friday evening. This evolution will promote
downstream ascent through impressive height falls paired with
modest jet streak amplification, leading to widespread deep layer
lift spreading into the Four Corners and southern Rockies Friday
into Saturday. The antecedent thermal structure will be modest for
snowfall (snow levels 8000-9000 ft), but increasing ascent within
a moistening column will expand precipitation and allow for snow,
which could be heavy, especially in the higher terrain of the
Sangre de Cristos, White Mountains, and San Juans, with some
dynamic cooling of the column possible later D3 as some deformation
develops across northern NM. Still a lot of uncertainty in the
exact evolution, but at this time WPC probabilities indicate a
moderate to high risk (50-90% chance) for at least 4 inches in the
higher terrain.


The probability of significant icing across the CONUS is less than
10 percent.


Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 111850
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
150 PM EST Wed Feb 11 2026

Valid 00Z Thu Feb 12 2026 - 00Z Sun Feb 15 2026


...Eastern Great Lakes & Central Appalachians...
Day 1...

Strong clipper system has exited into the eastern Atlantic and set
up a CAA regime through tonight with modest northwesterly flow and
850 mb temperatures as low as -15C. This will lead to continued lake-enhanced/upslope snowfall into the favorable terrain from the
central Appalachians through the eastern Great Lakes and northern
New England ranges. However, this period of light to moderate snow
will be short-lived as high pressure builds in over the Mid-
Atlantic on Friday and the next weak clipper approaches New England
Friday night. WPC probabilities are low (<20%) for most regions
outside of the Laurel Highlands of southwest PA and areas downwind
of Lake Ontario.


...Sierra Nevada to the Central/Southern Rockies...
Days 1-2...

A closed mid-level low positioned along the coast of northern CA
will generally fill in place as the accompanying longwave trough
elongates back to the southwest as secondary vorticity energy
rotates through the base ot approach southern CA and Baja by Friday
morning. This stalled evolution will result in a resurgence of an
upper level jet streak to sharpen downstream of this trough axis,
and while the secondary jet streak tonight into Thursday won't be
as powerful as the lead jet, it will maintain moisture advection
and broad LFQ diffluent ascent from CA into the Central Rockies.
The overlap of this jet streak with broad but persistent SW mid-
level flow also downstream of the primary trough axis will surge
moisture eastward as far as CO as reflected by NAEFS IVT
percentiles surging to above the 99th percentile in CO, with
prolonged anomalies above the 90th percentile back into the Great
Basin.

This plume of moisture will be primarily shed eastward within a WAA
plume, so snow levels will be generally 6000-7000 ft, lowering
slowly as the trough axis pivots eastward, but this will likely be
accompanied by rapid drying and a resulting cutoff of
precipitation. For this reason, the heaviest snowfall accumulations
are likely to be above 7000 ft (as high as 8000 ft in CO), with a
wane in precipitation expected as snow levels fall. WPC
probabilities D1 are high for at least 6 inches of snow in the
Uintas/Wasatch, the Tetons/Wind Rivers, and parts of the CO Rockies
including the Park Range. D2 probabilities compress and fall
rapidly, leading to just residual elevated probabilities above 20%
for 4+ inches in the CO Rockies. Most probabilities drop off below
20% after 00z tonight in Sierra given a majority of the
precipitation occurs prior to 00z tonight.


...Southern Rockies...
Day 3...

The same secondary shortwave responsible for elongating the trough
over CA/Great Basin D2 will shed eastward Friday morning, moving
across southern CA/Baja Norte before closing off once again near
the Four Corners Friday evening. This evolution will promote
downstream ascent through impressive height falls paired with
modest jet streak amplification, leading to widespread deep layer
lift spreading into the Four Corners and southern Rockies Friday
into Saturday. The antecedent thermal structure will be modest for
snowfall (snow levels 8000-9000 ft), but increasing ascent within
a moistening column will expand precipitation and allow for snow,
which could be heavy, especially in the higher terrain of the
Sangre de Cristos, White Mountains, and San Juans, with some
dynamic cooling of the column possible later D3 as some deformation
develops across northern NM. Still a lot of uncertainty in the
exact evolution, but at this time WPC probabilities indicate a
moderate risk (40-70% chance) for at least 4 inches in the higher
terrain.


...Washington Cascades...
Day 3...

By late day 2 into day 3, the next upper trough to approach the
West Coast from the Gulf of Alaska orients a weak axis of IVT (<300
kg/m/s) into the Cascades. Snow levels start out rather low and are
forecast to drop below 2,000 ft and below pass level. However,
precipitation amounts appear light enough to avoid heavier snow
amounts. Still, WPC probabilities for at least 4 inches of snow are
high (>70%) in the Cascades above about 4,000 feet. Probabilities
for at least 4 inches of snow for Stevens and Snoqualmie passes
are between 20-40%.


The probability of significant icing across the CONUS is less than
10 percent.


Snell/Weiss


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 120819
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
319 AM EST Thu Feb 12 2026

Valid 12Z Thu Feb 12 2026 - 12Z Sun Feb 15 2026


...Central & Southern Rockies...
Days 1-2...

A broad upper-level trough west of Baja California is funneling
anomalous moisture into the Four Corners region today with modest
500-700mb Q-vector convergence over the central Rockies. The lack
of a continental polar (cP) airmass is keeping periods of snow
confined to elevations above 8,000ft in the Wasatch and CO Rockie
today and into Thursday night. A brief lull in the snowfall occurs
Thursday night, but heavier snowfall returns to the Central and
Southern Rockies on Friday as the aforementioned upper trough
moves east towards AZ. 700-500mb height falls, 500mb PVA, and PWs
above the 90th climatological percentile will support mountain
snow as far south as the Gila Mountains to as far east as the
Sangre De Cristo range. Similar to Thursday's snowfall, the lack of
a reasonably cold airmass will keep snow levels above 7,000ft,
with the heavier snowfall totals residing above 8,000ft. The
increased upper-level synoptic-scale forcing will improve snowfall
rates in the higher terrain compared to Thursday. 48-hour WPC
probabilities show low-to-moderate chances (40-60%) for snowfall
totals >4" in the Wasatch, the AZ Gila Mountains, and the CO/NM
Rockies, with the higher confidence in snowfall >4" being above
9,000ft. In the peaks of the CO Rockies and Gila Mountains, there
are some low chance probabilities (<30%) for snowfall totals >8"
through Saturday morning.

...Northern New York...
Days 2-3...

A progressive 500mb vorticity max over Ontario Friday afternoon
will provide sufficient upper-level ascent atop a low-level warm
front driven by a narrow sliver of 850mb WAA. Guidance is coming
into better agreement on a period of moderate snow, potentially
falling heavily at times, along the shores of Lake Ontario on east
into the Tug Hill and Adirondacks Friday night. Mean flow out of
the NW with residual 700-300mb moisture will support lingering
periods of snow into the Tug Hill and Adirondacks into Saturday
morning before tapering off by Saturday afternoon. Most snowfall is
likely to range between a coating-3" for much of northern New
York, although the Tug Hill and Adirondacks do show low chances
(<20%) for localized amounts >4" through Saturday morning.

...Washington Cascades & Northern Rockies...
Days 2-3...

An upper-level trough in the Gulf of Alaska will dive south just
off the coast of British Columbia and direct a plume of rich
Pacific moisture at the Pacific Northwest Friday afternoon and
through Saturday morning. A passing cold front and height falls in
advance of the encroaching upper trough will cause snow levels to
drop as low as 2,000ft in the Olympics and Cascades. Elevations in
the WA Cascades above 4,000ft sport the better chances for snowfall
amounts surpassing 6", while most elevations below 3,000ft range
between a coating-3". WPC probabilities for at least 4 inches of
snow for Stevens and Snoqualmie passes are between 30-50%. The
plume of Pacific moisture spills eastward into the Northern Rockies
with the Bitterroots, Sawtooth, and Lewis Ranges most likely to
receive measurable snowfall starting Friday evening and continuing
throughout the day Saturday. Similar to the Cascades, most snowfall
totals will be minor (coating-3"), although some localized totals

6" in the peaks of the Bitterroots and Lewis Range are possible.

The probability of significant icing across the CONUS is less than
10 percent.


Mullinax





$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 121815
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
115 PM EST Thu Feb 12 2026

Valid 00Z Fri Feb 13 2026 - 00Z Mon Feb 16 2026


...Central & Southern Rockies...
Days 1-2...

A broad upper-level trough lifting northeastward over Baja
California will continue to funnel anomalous moisture into the
southern Rockies region through Friday with modest 500-700mb
Q-vector convergence over the central Rockies. The lack of a
continental polar (cP) airmass is keeping periods of snow confined
to elevations above 8,000ft in the Wasatch and CO Rockies into
Thursday night. A brief lull in the snowfall occurs Thursday night,
but heavier snowfall returns to the Central and Southern Rockies
on Friday as the aforementioned upper trough moves east towards AZ.
700-500mb height falls, 500mb PVA, and PWs above the 90th
climatological percentile will support mountain snow as far south
as the Gila Mountains to as far east as the Sangre De Cristo range.
Similar to Thursday's snowfall, the lack of a reasonably cold
airmass will keep snow levels above 7,000ft, with the heavier
snowfall totals residing above 8,000ft. The increased upper-level synoptic-scale forcing will improve snowfall rates in the higher
terrain compared to Thursday. 48-hour WPC probabilities show low-
to-moderate chances (40-60%) for snowfall totals >4" in the
Wasatch, the AZ Gila Mountains, and the CO/NM Rockies, with the
higher confidence in snowfall >4" being above 9,000ft. In the peaks
of the CO Rockies and Gila Mountains, there are some low chance
probabilities (<30%) for snowfall totals >8" through Saturday.


...Northern New York...
Days 2-3...

A progressive 500mb vorticity max over Ontario Friday afternoon
will provide sufficient upper-level ascent atop a low-level warm
front driven by a narrow sliver of 850mb WAA. Guidance is coming
into better agreement on a period of moderate snow, potentially
falling heavily at times, along the shores of Lake Ontario on east
into the Tug Hill and Adirondacks Friday night. Mean flow out of
the NW with residual 700-300mb moisture will support lingering
periods of snow into the Tug Hill and Adirondacks into Saturday
morning before tapering off by Saturday afternoon. Most snowfall is
likely to range between a coating-3" for much of northern New
York, although the Tug Hill and Adirondacks do show low chances
(<20%) for localized amounts >4" through Saturday morning.


...Cascades & Northern Rockies...
Days 2-3...

An upper-level trough in the Gulf of Alaska will dive south just
off the coast of British Columbia and direct a plume of rich
Pacific moisture at the Pacific Northwest Friday afternoon and
through Saturday morning. A passing cold front and height falls in
advance of the encroaching upper trough will cause snow levels to
drop as low as 2,000ft in the Olympics and Cascades. Elevations in
the WA Cascades above 4,000ft sport the better chances for snowfall
amounts surpassing 6", while most elevations below 3,000ft range
between a coating-3". WPC probabilities for at least 4 inches of
snow for Stevens and Snoqualmie passes are between 30-60%. The
plume of Pacific moisture spills eastward into the Northern Rockies
with the Bitterroots, Sawtooth, and Lewis Ranges most likely to
receive measurable snowfall starting Friday evening and continuing
throughout the day Saturday. Similar to the Cascades, most snowfall
totals will be minor (coating-3"), although some localized totals

6" in the peaks of the Bitterroots and Lewis Range are possible.

Lastly, the passing cold front will sink southward over the OR
Cascades as snow levels remain around 4,000ft.


...California...
Day 3...

By the end of Day 3 (00z Mon), the upper trough approaching the
West Coast is forecast to deepen into an anomalous upper low (below
the 1st climatological percentile per the 00z NAEFS). In response,
subtropical moisture will begin to move inland across northern
California ahead of the cold front extending on the eastern
periphery of the upper level system. Snow levels are expected to
start around 5,000ft during this time frame. WPC probabilities
currently reach 40-60% for at least 8 inches of snowfall across the
Klamath Mts and Shasta Siskiyous. Much heavier snowfall is
forecast across the Sierra Nevada and the California ranges after
00z Mon, see WPC's extended range discussion for more information.



The probability of significant icing across the CONUS is less than
10 percent.


Snell/Mullinax




$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 130819
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
319 AM EST Fri Feb 13 2026

Valid 12Z Fri Feb 13 2026 - 12Z Mon Feb 16 2026


...Central & Southern Rockies...
Days 1-1.5...

A broad upper-level trough lifting northeastward over Baja
California will continue to funnel anomalous moisture into the
Four Corners region today with 500-700mb Q-vector convergence over
the central and southern Rockies. The lack of a continental polar
(cP) airmass is keeping periods of snow confined to elevations
above 8,000ft throughout the Four Corners' mountain ranges today
and into early Saturday morning. 700-500mb height falls, 500mb PVA,
and PWs above the 90th climatological percentile will support
mountain snow as far south as the Gila Mountains to as far east as
the Sangre De Cristo range. The increased upper-level synoptic-
scale forcing will improve snowfall rates in the higher terrain
with >1"/hr rates at times. 48-hour WPC probabilities show
modertae-to-high chances (50-80%) for snowfall totals >4" in the
AZ Gila Mountains and the CO/NM Rockies, with the higher
confidence in snowfall >6" being above 9,000ft. In the peaks of
the CO Rockies and Gila Mountains, there are some low chance
probabilities (<30%) for snowfall totals >8" through Saturday
morning.


...Northern New York...
Day 1...

A progressive 500mb vorticity max over Ontario Friday afternoon
will provide sufficient upper-level ascent atop a low-level warm
front driven by a narrow sliver of 850mb WAA. Guidance is coming
into better agreement on a period of moderate snow, potentially
falling heavily at times, along the shores of Lake Ontario on east
into the Tug Hill and Adirondacks Friday night. Mean flow out of
the NW with residual 700-300mb moisture will support lingering
periods of snow into the Tug Hill and Adirondacks into early
Saturday morning before tapering off by midday. Most snowfall is
likely to range between a coating-3" for much of northern New York,
although the Tug Hill features low chances (<20%) for localized
amounts >4" through Saturday morning.


...Cascades & Northern Rockies...
Days 1-3...

An upper-level trough in the Gulf of Alaska will dive south just
off the coast of British Columbia and direct a plume of rich
Pacific moisture at the Pacific Northwest this afternoon and
into Saturday. A passing cold front and height falls in advance of
the encroaching upper trough will cause snow levels to drop as low
as 2,000ft in the Olympics and Cascades. Elevations in the WA
Cascades above 4,000ft sport the better chances for snowfall
amounts surpassing 6", while most elevations below 3,000ft range
between a coating-3". WPC probabilities for at least 4 inches of
snow for Stevens and Snoqualmie passes are between 40-60%. The
plume of Pacific moisture spills eastward into the Northern Rockies
with the Bitterroots, Sawtooth, and Lewis Ranges most likely to
receive measurable snowfall starting Friday evening and continuing
throughout the day Saturday. The Northern Rockies will remain
downstream of a robust 250mb jet streak and steady 500mb PVA
advection through Sunday as well, keeping snow in the forecast
through the weekend's conclusion. Similar to the Cascades, most
snowfall totals will be minor (coating-3") at the lower elevations.
For the more remote elevations above 5,000ft in the Bitterroots and
Lewis Range, 2-hour WPC probabilities show moderate-to-high chances
(50-80%) for snowfall totals >8" with totals surpassing 12" above
6,000ft in the Lewis Range. Meanwhile, as the passing cold front
will sinks southward over the OR Cascades, snow levels will remain
around 4,000ft with most heavy snowfall staying in the more
remote/volcanic peaks.


...California...
Days 2.5-3...

A potent closed 500mb low west of CA will emanate healthy 500mb PVA
over the Golden State as early as Sunday afternoon with diffluent
flow at the nose of a strengthening 500mb jet streak. Increasing 850-300mb moisture ahead of the trough steadily increases over northern CA
with periods of mountain snow unfolding in the Siskiyou/Shasta. The
500mb low by Sunday night is a robust one, highlighted by 500mb
heights per ECMWF that are below the 1st climatological percentile.
Ahead of the upper low, a 500-750 kg/m/s IVT will direct
subtropical East Pacific moisture northward into the Sierra Nevada
by early Monday morning with snow levels down to 5,000ft. Sunday
night into early Monday morning marks the beginning of a multi-day
barrage of heavy mountain snow throughout much of the Golden State
with heavy snow eventually starting to accumulate during the day
Monday as far south as the Transverse and Peninsula Ranges down to
5,000ft. See WPC's extended range discussion for more information,
but it is worth noting WPC's WSSI-P shows moderate-to-high chances
(50-70%) for Major impacts in the central and southern Sierra
Nevada on Presidents' Day that then jump to >70% for all of the
Sierra Nevada above 6,000ft by Tuesday. Residents and those
traveling through passes in California next week should monitor
the forecast closely in the coming days.


...Central Appalachians & Mid-Atlantic...
Day 3...

...High confidence in a moisture-latent storm system, low
confidence in precipitation-type from the Appalachians to the I-95
corridor...

A sharp 500mb trough tracking through the Lower MS Valley early
Sunday morning will tap into ample Gulf moisture and direct it
northeast into the southern and central Appalachians. In addition,
a strong >140kt jet streak southeast of the MA Capes is placing its
diffluent right-entrance region over the Mid-Atlantic, providing
excellent upper-level divergence aloft. Guidance is in good
agreement on a rather strong surface low (sub 1000mb low) tracking
across northern MS/AL that, according to the ECMWF, is highly
anomalous, with the aforementioned pressure being below the 1st
climatological percentile. The integrated vapor transport (IVT)
over the Southeast tops 750 kg/m/s, exceeding the 97.5
climatological percentile, and results in moderate-to-heavy
precipitation moving into the Mid- Atlantic Sunday morning and
through Sunday evening.

While there is no shortage of moisture at this system's disposal,
the cold airmass in advance of the storm is quite marginal. Despite
the presence of high pressure over New England, the temperature
regime associated with this high pressure is not particularly cold
at all. Using a combination of GEFS/EPS percentiles, 10th
percentile temperatures in northern MD are 32-34F, with 50th
percentile values in the mid 30s. Meanwhile, dew points are likely
to range between the upper 20s and low 30s. The resulting wet-bulb
temperatures at the surface tend to hover around or slightly above
freezing in central Appalachians, northern VA, northern MD, and the
DelMarVa Peninsula. With temperatures in the surface-850mb layer
being isothermal along the 0C isotherm to even 1-2C above freezing,
the potential for snowfall will be heavily dependent upon
elevation and dynamic cooling via strong vertical velocities and
heavy precipitation rates. This system is very much more of a
March-like storm system, where mesoscale banding and elevation are
the primary methods for which accumulating snow would occur.

WPC probabilities are not overly impressed at this time with <30%
chances for over 1" of snowfall in the central Appalachians and
northern Mid-Atlantic. Given the lack of a thermally-supportive
boundary layer via marginal wet-bulb temperatures, it will prove
difficult to support a widespread snow event. However, as the event
encroaches upon the hi-res CAMs guidance window, confidence in
whether a narrow swath of measurable snow from the central
Appalachians to the Mid-Atlantic I-95 corridor will come into
better focus. For now, residents in the central Appalachians and
Mid-Atlantic should, at minimum, expect a dreary/wet Sunday with
the potential for some snow mixing in over elevated terrain.


The probability of significant icing across the CONUS is less than
10 percent.


Mullinax






$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 131929
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
229 PM EST Fri Feb 13 2026

Valid 00Z Sat Feb 14 2026 - 00Z Tue Feb 17 2026


...Central & Southern Rockies...
Day 1...

A sharp upper trough over AZ/northern Mexico this evening will
continue eastward tonight and reach West Texas tomorrow afternoon.
Moisture anomalies are high, but mostly in the warm sector.
However, the northern reaches of PW anomalies >97th percentile
overnight over the San Juans and Sangre de Cristos will support
mountain snow that will fall heavy at times through Saturday
morning. The progressive movement will limit accumulations, but SW
flow this evening will capitalize on upslope potential in the
terrain until the trough axis passes through. WPC probabilities for
at least 4 inches of snow are >50% above 10,000ft as snow levels
are rather high.


...Central/Western/Upstate New York...
Day 1...

A compact mid-level shortwave will move quickly out of Ontario and
through western/central NYS overnight, aiding in producing some
generally light snow across the region with the potential for some
locally moderate snow at times that will end on Saturday morning.
Most snowfall is likely to range between a coating-3" for much of
Upstate New York.


...Cascades & Northern Rockies...
Days 1-3...

Troughing west of the BC and the Pac NW will dig southward into an
upper low west of NorCal. This will send a modest cold front into
the Cascades and northern Rockies tonight/Saturday and linger
across the region as the flow remains generally from the southwest
aloft. Snow levels initially around 3500-4000ft will drop to around
2000-3000ft overnight into Saturday, bringing snow to many of the
passes. Moisture will continue eastward to the northern Rockies
(northern ID to northwestern MT) and the typical higher elevations
above 5000ft will see light to modest snowfall. Snow will end in
the Cascades during the day Saturday and diminish (though not truly
end) over the Rockies into Sunday as onshore flow continues in
some form. Another surge of moisture will bring light snow to the
Cascades by Monday with even lower snow levels to around 1000ft
(north) to 2000 ft (south) in the Cascades, but with light amounts.
For day 1, WPC probabilities for at least 4 inches of snow are

30% for Stevens and Snoqualmie passes. Into Monday night (late day

3), WPC probabilities for at least 2 inches of snow are >30% into
elevations as low as 2500-3000ft.


...California...
Days 2-3...

Southern extent of the anomalously deep troughing affecting the
Pacific Northwest (above) will result in a period of moderate to
locally heavy mountain snow for the Sierra Sunday into at least
Monday. A surface cold front, tied to an occluding low, will slowly
move onshore as a 120kt jet streak promotes heavier snowfall into
the Sierra Monday. Moisture will be modest (500-750 kg/m/s IVT and
PWs touching the 90th percentile) with the best moisture flux just
south of the region into AZ. Snow levels will generally range from
4500ft to 6000ft from north to south on Monday, then fall by the
end of this forecast period in northern areas to below 4000ft as
the trough approaches (and lower thereafter). Snow will continue
beyond this forecast period with major impacts to at least the high
Sierra per the WSSI-P probabilities (>50%) that increase into the
medium range (>80-90%). WPC probabilities for at least 18 inches of
snow are >50% above 6000-7000ft or so.


...Central Appalachians & Mid-Atlantic...
Days 2.5-3...

A southern system will likely slide eastward late Sun into Mon
with some light wintry precipitation on the northern side, but
trends are toward less QPF in a marginally conducive environment
and probabilities for even light snow are low.


The probability of significant icing across the CONUS is less than
10 percent.


Fracasso


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 140832
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
332 AM EST Sat Feb 14 2026

Valid 12Z Sat Feb 14 2026 - 12Z Tue Feb 17 2026


...Cascades...
Days 1 & 3...

A broad upper-level troughing pattern off the Pacific NW coast
will continue to supply lingering low-mid level moisture that
allows for light snow through this morning. Snow levels will drop
to as low as 2000-3000ft today and into Saturday evening, bringing
snow to many of the passes over the WA Cascades. Following a lull
in snowfall Saturday night and into Sunday, another surge of
moisture will be supplied by a strengthening 500mb closed-low west
of British Columbia. Sharp height falls and excellent 500mb PVA
will be paired with an influx of 850-300mb mean-layer moisture to
produce periods of snow. Snow levels will plummet to as low as
800ft around the WA Cascades, while 2000 ft snow levels in the OR
Cascades will be more common. While these snow levels are getting
quite low, snowfall totals below 2,000ft in the WA/OR Cascades will
remain light. The heaviest snowfall will reside above 3,000ft
72-hour WPC probabilities show moderate chances (40-60%) for
snowfall totals >4" for both Snoqualmie Pass and Stevens Pass.
Given the long duration but lack of heavy hourly rates, WSSI-P
shows the chances for Minor Impacts are generally on the low side
(20-40%) with Monday having the best chances for some slick travel
conditions at pass level.


...California...
Days 2-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges beginning Sunday and continuing into
next week...

A pair of potent Pacific storm systems will work together to direct
copious amounts of moisture at the mountain ranges of the "Golden
State" starting Sunday. The first upper low west of California will
kickoff this multi-day heavy snow event on Sunday with snow falling
in the higher terrain of the Siskiyou, Shasta, and Salmon
Mountains. By Sunday night the upper low approaches, causing
heights to fall over CA and the strengthening IVT to direct
subtropical moisture at the state. Monday marks the beginning of
heavy snowfall along the Sierra Nevada with snow levels will
generally ranging from 4500ft to 6000ft from north to south
initially, then fall below 3000ft across northern CA as the other
potent Pacific trough approaches from the northwest. In both cases,
the state will be placed ahead of a pair of 500mb jet streaks that
will generate excellent upper-level divergence aloft, along with a
barrage of Pacific moisture and strong topographically-enhanced
snowfall rates. Heavy snowfall is expected as far south as the
Transverse Ranges above 6,000ft with WPC probabilities showing
moderate chances (40-60%) for snowfall totals >8" in the peaks of
the San Gabriel and San Bernadino Mountains.

California's mountain ranges welcome the snow, although it will
come down fast and furious on Monday and continue into Tuesday.
Through the end of this discussion's timeframe (12Z Tues), multiple
feet of snow will have fallen above 6,000ft along the Sierra
Nevada. WPC probabilities show high chances (>70%) for >24" of
snow having fallen along the I-80 pass by 12Z Tuesday and more snow
still to come. The WSSI-P depicts a highly impactful snow event
along the Sierra Nevada with high chances (>70%) for Major Impacts
above 6,00ft, including the I-80 pass. In fact, for the higher
elevations above 8,000ft, the WSSI-P shows moderate chances (>50%)
for Extreme Impacts, suggesting the potential for significant
impacts to infrastructure. Travel will be dangerous to impossible
in the Sierra Nevada into Tuesday. Note that there are also high
chances (>70%) for Minor Impacts for I-5 around Mount Shasta,
signifying potential travel delays for I-5 in the more elevated
terrain of northern CA.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West this weekend and into early
next week. With a lack of a frigid airmass ahead of this healthy
moisture source, snow will largely be confined to many of the
taller mountain peaks that sorely need beneficial snowpack. The
heaviest snowfall will reside in the Bitterroots, the Lewis Range,
Sawtooth, and the Blue Mountains whee 72-hour WPC probabilities
show moderate-to-high chances (50-80%) for snowfall totals >8".
Localized amounts ranging between 12-24" are most likely to occur
along the remote reaches of the Lewis Range and peaks of the Blue
Mountains. Farther south, most accumulations in the Great Basin,
the Wasatch, Uinta, Mogollon Rim, and CO/NM Rockies will be on the
lighter side. The peaks around Zion Nat'l Park on north along the
Wasatch sport moderate-to-high chances (50-70%) for snowfall totals

4". Otherwise, most mountain ranges are likely to see 1-4" of

snowfall, with additional snowfall still to come on Tuesday.


...Northeast...
Day 2...

The last 24 hours have seen some model guidance (GFS/ECMWF)
gradually creep north with the precipitation shield. This is due to
the approaching 500mb shortwave over western PA coming in
stronger, thus leading to healthier PVA aloft and more 250mb jet
streak enhancement aloft. While boundary layer temperatures along
I-95 south of Philadelphia remain quite marginal on Sunday,
elevated terrain north and west of the Delaware River are likely to
have better chances to see wet snow Sunday afternoon. As the upper
trough in the Carolinas spawns low pressure over the NC Outer
Banks Sunday evening, 850-700mb WAA to the north of the low will
support narrow banding of snow from eastern PA and northern NJ to
the NYC metro, Long Island, and coastal southern New England. There
remains notable spread in model guidance in the position of this
band, but trends in not only the GFS/ECMWF guidance but also their
AI counterparts are showing additional support for a ribbon of
light snow. WPC probabilities show low-to-moderate chances (30-50%)
for snowfall totals >1" from the Delaware and Lehigh Valleys on
east to Long Island, but probabilities for >2" of snowfall are
<20%, showing that most totals are minor and likely to range
between a coating-2". There is the potential for additional
changes to this forecast in the next 12-24 hours.


The probability of significant icing across the CONUS is less than
10 percent.


Mullinax





$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 141922
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
222 PM EST Sat Feb 14 2026

Valid 00Z Sun Feb 15 2026 - 00Z Wed Feb 18 2026


...Cascades...
Days 1 & 3...

A shearing apart weak trough across Washington State will provide
weak forcing for light snow for many of the passes over the
Cascades. Meanwhile, snow levels will drop to as low as
1,000-2,000ft through Sunday. For the most part, there will be a
lull in snowfall tonight and into Sunday. On Monday, another surge
of moisture will be supplied by a second strengthening 500mb
closed-low west of British Columbia, which will dive parallel to
the coast through Tuesday. Sharp height falls and excellent 500mb
PVA will be paired with an influx of 850-300mb mean-layer moisture
to produce periods of snow. Snow levels will plummet to as low as
800ft around the WA Cascades, while 2000 ft snow levels in the OR
Cascades will be more common. While these snow levels are getting
quite low, snowfall totals below 2,000ft in the WA/OR Cascades will
remain light. The heaviest snowfall will reside above 3,000ft
where 72-hour WPC probabilities remain in the moderate range
(40-60%) for snowfall totals >4" for both Snoqualmie Pass and
Stevens Pass. Given the long duration but lack of heavy hourly
rates, WSSI-P shows the chances for Minor Impacts are generally on
the low side (20-40%) with Monday having the best chances for some
slick travel conditions at pass level.


...California...
Days 2-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges beginning Sunday and continuing into
next week...

A pair of potent Pacific storm systems will work together to direct
copious amounts of moisture at the mountain ranges of the "Golden
State" starting Sunday. A broad positively-tilted upper-level troughing
pattern off the Pacific NW coast will supply low-mid level
moisture that allows for light snow through tonight into the
higher terrain of the Siskiyou, Shasta, and Salmon Mountains. Snow
levels will gradually drop below 5,000 ft into these ranges, where
1-2 feet of new snow accumulation are possible at the higher
elevations through the day Sunday.

By Sunday night the upper low approaches, causing heights to fall
over CA and the strengthening IVT to direct subtropical moisture at
the state. Monday marks the beginning of heavy snowfall along the
Sierra Nevada with snow levels will generally ranging from 4,500ft
to 6,000ft from north to south initially, then fall below 3,000ft
across northern CA as the other potent Pacific trough approaches
from the northwest. In both cases, the state will be placed ahead
of a pair of 500mb jet streaks that will generate excellent upper-
level divergence aloft, along with a barrage of Pacific moisture
and strong topographically-enhanced snowfall rates. Heavy snowfall
is expected as far south as the Transverse Ranges above 6,000ft
with WPC probabilities showing low to moderate chances (30-50%) for
snowfall totals >8" in the peaks of the San Gabriel and San
Bernadino Mountains.

California's mountain ranges welcome the snow, although it will
come down fast and furious on Monday and continue into Tuesday.
Through the end of this discussion's timeframe (00Z Wed), multiple
feet of snow will have fallen above 6,000ft along the Sierra
Nevada. WPC probabilities show high chances (>70%) for >24" of snow
having fallen along the I-80 pass by 12Z Tuesday and more snow
still to come. The WSSI-P depicts a highly impactful snow event
along the Sierra Nevada with high chances (>70%) for Major Impacts
above 6,000ft, including the Donner Pass. In fact, for the higher
elevations above 8,000ft from Lake Tahoe south, the WSSI-P shows
high chances (>70%) for Extreme Impacts, suggesting the potential
for significant impacts to infrastructure. Travel will be dangerous
to impossible in the Sierra Nevada into Tuesday. Note that there
are also high chances (>70%) for Minor Impacts for I-5 around Mount
Shasta, signifying potential travel delays for I-5 in the more
elevated terrain of northern CA.

By Tuesday, another round of heavy snow is expected into all of the
ranges of central and northern California as a strong upper level
low dives south along the coast, locally enhancing onshore flow and
moisture levels on the leading (southern) edge of the low. Snow
levels will fall to around 2,000 ft in far northern California to
below 5,000 ft into the Transverse Ranges. Storm total snow amounts
will approach 3 feet into the Shasta and Siskiyou ranges, over 4
feet across much of the Sierra Nevada, and amounts over a foot even
into the highest elevations of the Transverse Ranges.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West this weekend and into early
next week. With a lack of a frigid airmass ahead of this healthy
moisture source, snow will largely be confined to many of the
taller mountain peaks that sorely need beneficial snowpack. The
heaviest snowfall will reside in the Bitterroots, the Lewis Range,
Sawtooth, and the Blue Mountains where 72-hour WPC probabilities
show moderate-to-high chances (50-80%) for snowfall totals >8".
Localized amounts ranging between 12-24" are most likely to occur
along the remote reaches of the Lewis Range and peaks of the Blue
Mountains. Farther south, most accumulations in the Great Basin,
the Wasatch, Uinta, Mogollon Rim, and CO/NM Rockies will be on the
lighter side. The peaks around Zion Nat'l Park on north along the
Wasatch sport moderate-to-high chances (50-70%) for snowfall totals

4". Otherwise, most mountain ranges are likely to see 1-4" of

snowfall through Monday.

On Tuesday, a "bowling ball" low tracking south down the coast will
help guide upper level energy sweeping across the Southwest towards
the northern Plains. The energy between these two features will
lead to cyclogenesis across the northwestern Plains (northern
Wyoming and southeast Montana). The low and the upper wave over the
Southwest will cause widespread heavy snow at the higher elevations
of many of the mountains from Utah and Colorado north. 24-hour snow
totals are likely to exceed 6 inches from southern Utah and
southwest Colorado up through the Lewis Range in northwestern
Montana. While lower elevations will be either snow-free or only
pick up an inch or two, the mountains will likely upslope much
higher snow totals. WSSI-P values are high (>70%) for over 8
inches of snow into all of those ranges.

...Northeast...
Day 2...

The beginning of phasing of two separate 500 mb troughs will drive
the potential for a period of light snow across portions of the
Mid-Atlantic Sunday night. A southern stream disturbance over the
Southeast Sunday evening will transfer its energy to an equally
fast-moving disturbance in the northern stream over eastern Ohio.
With the northern disturbance intensifying, this will lead to
healthier PVA aloft and more 250mb jet streak enhancement aloft.
While boundary layer temperatures along I-95 south of Philadelphia
remain quite marginal on Sunday, a corridor from west of
Philadelphia through the city and east to NYC and Long Island look
to have the best potential for light snow Sunday night. The
weakening trough in the Carolinas spawns low pressure over the NC
Outer Banks Sunday evening, allowing 850-700mb WAA to the north of
the low to support narrow banding of snow from eastern PA and
northern NJ to the NYC metro, Long Island, and coastal southern New
England. There remains notable spread in model guidance in the
position of this band, but trends in not only the GFS/ECMWF
guidance but also their AI counterparts are showing additional
support for a ribbon of light snow. WPC probabilities show low-to-
moderate chances (30-50%) for snowfall totals >1" from the Delaware
and Lehigh Valleys on east to Long Island, but probabilities for

2" of snowfall are <20%, showing that most totals are minor and

likely to range between a coating-2".

The probability of significant icing across the CONUS is less than
10 percent.


Wegman/Mullinax








$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 150732
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
232 AM EST Sun Feb 15 2026

Valid 12Z Sun Feb 15 2026 - 12Z Wed Feb 18 2026


...Cascades & Olympics...
Days 2-3...

On Monday, a strengthening 500mb closed-low west of British
Columbia will slide south and just off the coast through Tuesday.
Sharp height falls and excellent 500mb PVA, combined with an
influx of 850-300mb mean-layer moisture and upslope enhancement,
will produce periods of snow over the Olympics and Cascades. Snow
levels will plummet to as low as 800ft around the WA Cascades and
Olympics, while 2000ft snow levels in the OR Cascades will be more
common. In fact, some of OR's coastal range could see snow to
elevations as low as 1,000ft. While these snow levels are getting
quite low, snowfall totals below 2,000ft in the WA/OR Cascades will
remain light. The heaviest snowfall will reside above 3,000ft
where 72-hour WPC probabilities remain in the moderate range
(40-60%) for additional snowfall totals >4" for both Snoqualmie
Pass and Stevens Pass. Given the long duration but lack of heavy
hourly rates, WSSI-P shows the chances for Minor Impacts are
generally on the low side (20-40%). Impacts are most likely to be a
combination of snow covered roads and reduced visibilities.


...California...
Days 2-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges beginning Sunday and continuing into
next week...

A pair of potent Pacific storm systems will work together to direct
copious amounts of moisture at the mountain ranges of the "Golden
State" beginning today and lasting into the middle of the upcoming
week. A broad positively-tilted upper level troughing pattern off
the Pacific NW coast will supply low-mid level moisture that
allows for light snow through tonight into the higher terrain of
the Siskiyou, Shasta, and Salmon Mountains. The heaviest snowfall
through Sunday are likely to reside above 5,000ft where 1-2 feet of
new snow accumulation are possible at the higher elevations
through Sunday night.

By Sunday night, the upper low approaches, causing mid-to-upper
level heights to fall over CA and the strengthening IVT to direct
subtropical moisture at the state. The state will be placed ahead
of a 500mb jet streak that will generate excellent upper- level
divergence aloft, along with a barrage of Pacific moisture and
strong topographically-enhanced snowfall rates. Monday marks the
beginning of heavy snowfall along the Sierra Nevada with snow
levels initially starting out around 6,000ft from north to south
initially, then falling to as low as 3,000ft by Monday night.
Farther north, snow level will dip below 3,000ft across northern CA
as the other potent Pacific trough approaches from the northwest.
Snowfall rates between 1-2"/hr will be common with some instances
of >3"/hr snowfall rates in the central and southern Sierra
Nevada. Heavy snow is also expected in the Transverse Ranges above
6,000ft.

By Tuesday, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second, strong upper
level low dives south along the West Coast, enhancing onshore flow
and supplying additional moisture on the southern and eastern
flanks of the upper low. Snow levels will fall to around 1,000 ft
in far northern California (including the northern coastal range),
around 2,500ft in the Sierra Nevada, and just below 5,000 ft into
the Transverse Ranges with snow continuing to fall across the
state's mountain ranges into Wednesday.

California's mountain ranges welcome the snow, although it will
come down fast and furious both Monday and Tuesday. Through the
end of this discussion's timeframe (12Z Wed), multiple feet of
snow will have fallen above 5,000ft along the Sierra Nevada. WPC
probabilities show high chances (>70%) for >30" of snow having
fallen along the I-80 pass by 12Z Wednesday and more snow still to
come. The WSSI shows a large swath of Extreme Impacts (Substantial
disruptions to daily life; extremely dangerous travel or impossible
driving conditions, extensive closures) for elevations generally
above 6,000ft, although some Extreme impacts as low as 5,000ft are
possible. Major to locally Extreme impacts are showing up in the
peaks of the San Gabriel and San Bernadino mountains, with mostly Moderate-to-Major Impacts (increasingly more disruptive to travel
jumping from Moderate to Major). Note that there are also Minor to
locally Moderate Impacts along I-5 around Mount Shasta, signifying
potential travel delays for I-5 in the more elevated terrain of
northern CA.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West today and into the upcoming
week. With a lack of a frigid airmass ahead of this healthy
moisture source, snow will largely be confined to many of the
taller mountain peaks that sorely need beneficial snowpack. The
heaviest snowfall will reside in the Bitterroots, the Lewis Range,
Sawtooth, and the Blue Mountains where Farther south, most
accumulations in the Great Basin, the Wasatch, Uinta, Mogollon Rim,
and CO/NM Rockies will be on the lighter side. The peaks around
Zion Nat'l Park on north along the Wasatch sport moderate-to-high
chances (50-70%) for snowfall totals >4". Otherwise, most mountain
ranges are likely to see 1-4" of snowfall through Monday.

On Tuesday, the highly anomalous upper-low off the Pacific NW coast
will help to usher the initial upper low over southern CA east into
the Intermountain West, causing widespread height falls and a
larger footprint of Pacific moisture to track through the Rockies.
Snow levels will lower to the valley floors in western Mt and
northern ID, with some light snow possible even in the Salt Lake
City area. Still, the lack of a frigid airmass at the surface will
keep the bulk of the heavy snow in the mountains with ranges such
as the Wasatch, Bear River, Tetons, Uinta, and Wind River seeing
locally heavy snowfall along their peaks. Many of the CO ROckies
will also receive snowfall, but the heavier amounts >8" will be
confined to elevations above 9,000ft.

72-hour WPC probabilities show high chances (>70%) for snowfall
totals >8" for most of the Intermountain West's ranges, but the
locally heavier total's (>12") are most likely to occur in the
peaks of the Lewis Range, the Bitterroots, Sawtooth, Blue, Bear
River, Wasatch, and Uinta.


...Upper Midwest & Great Lakes...
Day 3...

By 12Z Tuesday, the remnant yet vigorous trough that was originally
over southern CA late Monday will race across the Rockies and
project excellent 500mb PVA over the northern High Plains. The
ECMWF SATs shows a roaring 150kt 200mb jet streak (wind speeds
topping the 99.5 climatological percentile) over the Southwest will
place its divergent left-exit region over the Great Plains. With
the aid of lee-side downsloping and low-level WAA across the
Plains, an exceptionally deep surface low will form over southern
MT that reaches as low as 980mb Tuesday morning, or MSLP values
that are below the 1st climatological percentile. As WAA ahead of
the warm front reaches across the Upper Midwest, strong isentropic
ascent will ensue as the warm/moist air runs into a colder/drier
air-mass over northern ND and northern MN. Precipitation initially
starting as rain Tuesday afternoon will changeover to snow over
northeast MT, northern ND, and as far east as the MN Arrowhead
Tuesday night. Meanwhile, from northern MN and northern WI to the
northern tier of Michigan's Mitten, the overrunning setup would
favor a wintry mix of sleet and freezing rain Tuesday night and
into Wednesday morning. WPC probabilities show low chances (10-30%)
for pockets of over one-tenth of an inch of ice accretion in parts
of northern WI and MI.

There remains a high degree of uncertainty in the storm track, as
well as when the transition to snow would occur. Snow beneath the
strengthening TROWAL over northeast MT and northern ND would
perhaps not only support heavy snow, but the impressive strength of
the cyclone itself would foster blowing snow on its northern and
western flanks.In terms of snowfall, the MN Arrowhead sports low-
to-moderate chances (30-50%) for >4" of snowfall through 12Z Wed.
Most of far northeast MT, northern ND, and northern MN have
moderate chances (40-60%) for >2" of snowfall, but this is an area
where any minor change in duration or placement in the deformation
axis could result in notable changes to the snowfall forecast.
Regardless, the pressure gradient will be tight enough to where all
of these areas have moderate chances (40-60%) for Minor Impacts
(per WSSI-P) due to some combination of snowfall amounts of blowing
snow through early Wednesday morning.


...Northeast...
Day 1...

The airmass in the northern Mid-Atlantic and latest guidance
continues to favor areas farther north from southeast PA across
the Delaware River and into NJ and as far east as Long Island for
light snowfall. WPC probabilities show low-to moderate chances
(30-50%) for snowfall totals >1" from the Delaware and Lehigh
Valleys on east to Long Island, but probabilities for >2" of
snowfall are <30%, indicating that most totals are minor and
likely to range between a coating-2" from southeast PA (with
elevation) on east through northern NJ and across the NYC metro.
Snow should peak in intensity Sunday night and conclude by Monday
morning.


Mullinax





$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 152000
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
300 PM EST Sun Feb 15 2026

Valid 00Z Mon Feb 16 2026 - 00Z Thu Feb 19 2026


...Cascades & Olympics...
Days 2-3...

On Monday, a strengthening 500mb trough will dig south down the
British Columbia coast towards Washington State. The trough will
quickly close off into a closed low west of British Columbia. The
upper low will continue south down the coast Tuesday, moving off
the coast of Washington. Then the low will drift east over the
state, as it re-opens up into a trough. With this very complex,
rapidly changing, but slow-moving upper level pattern evolution, a
prolonged period of active weather is expected into the Pacific
Northwest.

Sharp height falls and excellent 500mb PVA, combined with an
influx of 850-300mb mean- layer moisture and upslope enhancement,
will produce periods of snow over the Olympics and Cascades. Snow
levels will plummet to as low as 600ft around the WA Cascades and
Olympics Monday morning, while 3,000ft snow levels in the OR
Cascades will be more common. Some of OR's coastal range could see
snow to elevations as low as 1,000ft on Tuesday. While these snow
levels are getting quite low, snowfall totals below 2,000ft in the
WA/OR Cascades will remain fairly light compared to many
winter time snow events. The heaviest snowfall is expected above
3,000ft where 72-hour WPC probabilities are now into the higher
moderate range (50-70%) for additional snowfall totals >4" for
both Snoqualmie and Stevens Passes. Given the long duration but
lack of heavy hourly rates, WSSI-P shows the chances for Minor
Impacts are generally on the low side (20-40%). Impacts are most
likely to be a combination of snow covered roads and reduced
visibilities.


...California...
Days 2-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges today and continuing into next week...

A pair of potent Pacific storm systems will work together to direct
copious amounts of moisture at the mountain ranges of the "Golden
State" beginning today and lasting well into the upcoming week. A
broad positively-tilted upper level troughing pattern off the
Pacific NW coast will supply low-mid level moisture that allows for
light snow through tonight into the higher terrain of the
Siskiyou, Shasta, and Salmon Mountains. The heaviest snowfall
totals through tonight will be above 5,000ft where 1-2 feet of new
snow accumulation are possible at the higher elevations.

Tonight, an upper-level trough that has thus far been far enough
off the coast to keep associated impacts minimal, will approach the
coast. Mid- to- upper level heights will fall over CA in response.
This will allow for strengthening IVT to direct subtropical
moisture at the state. The state will be placed ahead of a 500mb
jet streak that will generate excellent upper- level divergence
aloft, along with a barrage of Pacific moisture and strong
topographically- enhanced snowfall rates.

Monday marks the beginning of very heavy snowfall along the Sierra
Nevada with snow levels initially starting out around 6,000ft,
then falling to as low as 3,000ft by Monday night in the northern
Sierra, and 4,000 ft for the southern Sierra Nevada. Snowfall rates
between 1-2"/hr will be common with some instances of >3"/hr
snowfall rates in the central and southern Sierra Nevada. Heavy
snow is also expected in the Transverse Ranges above 6,000ft.

On Tuesday, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second, arguably stronger
upper level low dives south along the West Coast, closely following
the first. This will spike onshore flow and additional moisture
supply on the southern and eastern flanks of the upper low. Snow
levels will fall to around 1,000 ft in far northern California
(including the northern coastal range) Tuesday night, around
2,500ft in the Sierra Nevada, and just below 5,000 ft into the
Transverse Ranges. Snow will continue to fall across the state's
mountain ranges into Wednesday, but diminishing in intensity
considerably by sunrise.

California's mountain ranges welcome the snow, although it will
come down fast and furious both tomorrow and Tuesday. Through the
end of this discussion's timeframe (00Z Thu), multiple feet of
snow are forecast above 5,000ft along the Sierra Nevada. WPC
probabilities show high chances (>70%) for >30" of snow along
Donner Pass through 00Z Thursday and more snow still to come. The
WSSI shows a large swath of Extreme Impacts (Substantial
disruptions to daily life; extremely dangerous travel or impossible
driving conditions, extensive closures) for elevations generally
above 6,000ft, although some Extreme impacts as low as 5,000ft are
possible. Major to locally Extreme impacts are showing up in the
peaks of the San Gabriel and San Bernadino mountains, with mostly Moderate-to-Major Impacts (increasingly more disruptive to travel
jumping from Moderate to Major). Note that there are also Minor to
locally Moderate Impacts along I-5 around Mount Shasta, signifying
potential travel delays for I-5 in the more elevated terrain of
northern CA.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West today and into the upcoming
week. With a lack of a frigid airmass ahead of this healthy
moisture source, snow will largely be confined to many of the
taller mountain peaks that sorely need beneficial snowpack. The
heaviest snowfall will reside in the Bitterroots, the Lewis Range,
Sawtooth, and the Blue Mountains. Farther south, most
accumulations in the Great Basin, the Wasatch, Uinta, Mogollon Rim,
and CO/NM Rockies will be on the lighter side. The peaks around
Zion Nat'l Park on north along the Wasatch sport high (>70%)
chances of 72-hour snow totals for snowfall totals over a foot
through Wednesday. Monday will be the quietest day with most
mountain ranges into eastern Washington, Oregon, Idaho, and western
Montana seeing 1-4" of snowfall through tomorrow.

On Tuesday, the highly anomalous upper-low off the Pacific NW coast
will help to usher the initial upper low over southern CA east into
the Intermountain West, causing widespread height falls and a
larger footprint of Pacific moisture to track through the Rockies.
Snow levels will lower to the valley floors in western Mt and
northern ID, with some light snow possible even in the Salt Lake
City area. Still, the lack of a frigid airmass at the surface will
keep the bulk of the heavy snow in the mountains with ranges such
as the Wasatch, Bear River, Tetons, Uinta, and Wind River seeing
locally heavy snowfall along their peaks. Many of the CO Rockies
will also receive snowfall, but the heavier amounts >8" will be
confined to elevations above 9,000ft.

72-hour WPC probabilities show high chances (>70%) for snowfall
totals >8" for most of the Intermountain West's ranges, but the
locally heavier total's (>12") are most likely to occur in the
peaks of the Lewis Range, the Bitterroots, Sawtooth, Blue, Bear
River, Wasatch, and Uinta.


...Upper Midwest & Great Lakes...
Day 3...

By 00Z Wednesday, the remnant yet vigorous negatively tilted
trough that was originally over southern CA late Monday will race
across the Rockies to the Dakotas. It will project excellent 500mb
PVA over the northern High Plains. The ECMWF SATs shows a roaring
150kt 200mb jet streak (wind speeds topping the 99.5 climatological
percentile) over the Southwest will place its divergent left-exit
region over the Great Plains. With the aid of lee-side downsloping
and low-level WAA across the Plains, an exceptionally deep surface
low will form over southern MT that reaches as low as 980mb Tuesday
morning, or MSLP values that are below the 1st climatological
percentile. As WAA ahead of the warm front reaches across the Upper
Midwest, strong isentropic ascent will ensue as the warm/moist air
runs into a colder/drier air-mass over northern ND and northern
MN. Precipitation initially starting as rain Tuesday afternoon will
changeover to snow over northeast MT, northern ND, and as far east
as the MN Arrowhead Tuesday night. Meanwhile, from northern MN and
northern WI to the northern tier of Michigan's Mitten, the
overrunning setup would favor a wintry mix of sleet and freezing
rain Tuesday night and into Wednesday morning. WPC probabilities
have increased and now show moderate chances (40-60%) for moderate
impacts (hazardous driving conditions requiring extra caution while
driving) due to ice accretion in parts of Michigan's Upper
Peninsula and extending to the northern tip of the mitten.
Accumulations in these areas could approach a quarter of an inch.

There remains a high degree of uncertainty in the storm track, as
well as when the transition to snow would occur. Snow beneath the
strengthening TROWAL over northeast MT and northern ND would
perhaps not only support heavy snow, but the impressive strength of
the cyclone itself would foster blowing snow on its northern and
western flanks. In terms of snowfall, the forecast probabilities
have dramatically increased. In portions of the MN Arrowhead,
chances are moderate-to-high (60-80%) for >8" of snowfall through
00Z Thu. Most of far northeast MT, northern ND, and northern MN
have moderate chances (50-70%) for >4" of snowfall, but this is an
area where any minor change in duration or placement in the
deformation axis could result in notable changes to the snowfall
forecast. Regardless, the pressure gradient will be tight enough to
where all of these areas have high chances (>80%) for Minor
Impacts (per WSSI-P) due to some combination of snowfall amounts of
blowing snow through the day on Wednesday.


...Northeast...
Day 1...

The latest high-resolution guidance continues to favor areas
from southeast PA across the Delaware River and into NJ and as far
east as Long Island for light snowfall. WSSI-P values have
decreased in this area to only a 10% chance of minor impacts in
this region. Most expected snow totals are minor and likely to
range between a coating-2" from southeast PA (with elevation) on
east through central NJ, whereas the NYC metro forecasts have
dropped below an inch. Snow should peak in intensity over the next
several hours and conclude tomorrow morning.


Wegman/ Mullinax






$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 160801
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
301 AM EST Mon Feb 16 2026

Valid 12Z Mon Feb 16 2026 - 12Z Thu Feb 19 2026


...Pacific Northwest...
Days 1-3...

A strengthening 500mb trough will dig south down the British
Columbia coast towards Washington State. The trough will quickly
close off into a closed low west of British Columbia Monday night
into Tuesday with 500mb heights below the 0.5 climatological
percentile. The low will drift east over the Columbia River Valley
Tuesday evening and open up into a trough early Wednesday morning.
Then as that low exits to the east, one more shortwave trough over
coastal British Columbia heads for the Olympic Peninsula Wednesday
night. With this very complex, rapidly changing, but slow-moving
upper level pattern evolution, a prolonged period of active weather
is expected over the Pacific Northwest.

Sharp height falls and excellent 500mb PVA, combined with an
influx of 850-300mb mean-layer moisture and upslope enhancement,
will produce periods of snow over the Olympics and WA/OR Cascades
through mid-week. Snow levels will plummet to as low as 500ft
around the WA Cascades and Olympics Monday night and into Tuesday
morning, while 2,000ft snow levels in the OR Cascades will be more
common. Some of OR's coastal range could see snow down to
elevations as low as 1,000ft on Tuesday, and even some very light
snow possible along I-5 from the Tacoma/Olympia area on south
through the Willamette Valley. The heaviest snowfall is expected
above 2,000ft where 72-hour WPC probabilities are now into the
higher moderate range (50-70%) for additional snowfall totals >8"
for snowfall in the lower WA Cascades and most of the OR Cascades.
WPC probabilities for snowfall >4" remain in the moderate range
(40-60%) for Snoqualmie and Stevens passes. Given the long duration
but lack of heavy hourly rates, WSSI-P shows the chances for Minor
Impacts are generally on the low side (20-40%). The only exception
is the OR Cascades where there are moderate chances (40-60%) for
Moderate Impacts (hazardous travel, some closures/delays possible)
above 1,000ft. Note that the WSSI-P does show low-to-moderate
chances (20-40%) for Minor Impacts along I-5 from Olympia on south
to Eugene Monday night and into Tuesday. Impacts are most likely to
be a combination of snow covered roads and reduced visibilities.


...California...
Days 1-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges this week...

A pair of potent Pacific storm systems are working together to
direct copious amounts of moisture at the mountain ranges of the
"Golden State". While heavy snow has been unfolding in the
Siskiyou, Shasta, Trinity, and Salmons mountains of northern CA
since Sunday, today marks the beginning of very heavy snowfall
along the Sierra Nevada with snow levels initially starting out
around 6,000ft, then falling to as low as 3,000ft by Monday night
in the northern Sierra, and 4,000 ft for the southern Sierra
Nevada. Snowfall rates between 1-2"/hr will be common with some
instances of >3"/hr snowfall rates in the central and southern
Sierra Nevada. Heavy snow is also expected in the Transverse Ranges
above 6,000ft.

On Tuesday, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second, arguably stronger
upper level low dives south along the West Coast, closely following
the first. This will spike onshore flow and additional moisture
supply on the southern and eastern flanks of the upper low. Snow
levels will fall to around 1,000 ft in far northern California
(including the northern coastal range) Tuesday night, around
2,500ft in the Sierra Nevada, and just below 5,000 ft into the
Transverse Ranges. Snow will continue to fall across California's
mountain ranges trough Wednesday as yet another 500mb shortwave
trough west of WA continues to sustain what feels like an endless
supply of Pacific moisture into the Golden State. With the longwave
trough overhead, snow levels could creep down as low as 1,000ft in
central CA and may support minor accumulations down to 1,000ft.

California's mountain ranges welcome the snow, although it will
come down fast and furious through mid-week. Through the end of
this discussion's timeframe (12Z Thu), snowfall will be measured
in feet above 4,000ft along the Sierra Nevada. WPC probabilities
show high chances (>90%) for >30" of snow along Donner Pass
through 12Z Thursday and more snow still to come. The WSSI shows a
large swath of Extreme Impacts (Substantial disruptions to daily
life; extremely dangerous travel or impossible driving conditions,
extensive closures) for elevations generally above 5,000ft,
although some Major impacts as low as 4,000ft are possible. Major
to locally Extreme impacts are showing up in the peaks of the San
Gabriel and San Bernadino mountains, with mostly Moderate-to-Major
Impacts (increasingly more disruptive to travel jumping from
Moderate to Major). There are also likely to be some Major impacts
in the Coastal Range of northwest CA above 2,000ft. Note that
there are Minor to locally Moderate Impacts expected along I-5
around Mount Shasta, signifying potential travel delays for I-5 in
the more elevated terrain of northern CA.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West this week that badly need the
boost in snowpack. With a lack of a frigid airmass ahead of this
healthy moisture source, the bulk of the heavy snow will be largely
confined to many of the taller mountain peaks that sorely need
beneficial snowpack. The heaviest snowfall on Monday will reside
in the Blue, Sawtooth, Wind River, Uinta, and as far south as Mt.
Charleston and the Mogollon Rim. WPC probabilities are high (>70%)
for snowfall totals >6" in these mountain ranges through Monday
night.

On Tuesday, the highly anomalous upper-low off the Pacific NW coast
will help to usher the initial upper low over southern CA east into
the Intermountain West, causing widespread height falls and a
larger plume of Pacific moisture to pass over the Rockies. The
potent closed low off the Pacific NW coast on Tuesday then heads
inland over the interior NW and northern Rockies on Wednesday,
prompting snow levels to crash and most valleys (except the
eastern WA Columbia River Basin) are likely to see at least a
coating of snow. Still, the lack of a frigid airmass at the surface
will keep the bulk of the heavy snow in the mountains with ranges
such as the Wasatch, Bear River, Tetons, Uinta, Wind River,
Mogollon Rim, and CO Rockies seeing anywhere from 1-2 feet of snow.
Expect Minor to Moderate Impacts, per the WSSI, with travel over
passes from the Lewis Range and Bitterroots to as far south as the
Mogollon Rim likely to contend with hazardous travel conditions.


...Northern Plains & Upper Great Lakes...
Days 2-3...

A powerful cyclone forming in the northern High Plains on Tuesday
will be the focus for heavy snow and blowing snow from northern MT,
as well as periods of snow and accumulating ice in the Upper
Midwest and Great Lakes Tuesday night. The storm system itself will
feature MSLP values in low-mid 980s over the Dakotas with blustery
winds in just about all quadrants of the storm. Beneath the TROWAL
over northeast MT and ND, hourly snowfall rates up to 1"/hr are
possible Tuesday night into Wednesday morning with wind gusts
topping 40 mph in eastern MT and western ND. Meanwhile, strong WAA
aloft overrunning a sub-freezing airmass will not only foster heavy
snow in northeast ND and northern MN, but also allow for freezing
rain to unfold from north-central MN on east through northern WI
and into northern MI. The worst of the icing is likely to occur
Tuesday night and into Wednesday morning in these areas. The
heaviest snowfall is expect to unfold in the MN Arrowhead where
lake-enhanced snowfall will play a vital role in areas receiving
over a foot of snow.

WPC probabilities feature moderate chances (40-60%) for ice
accumulations over one-tenth of an inch over the tip of Michigan's
Mitten, as well as along the southern shores of the Upper
Peninsula. In terms of snowfall, WPC probabilities show moderate-
to-high chances (50-70%) for snowfall totals >4" from northeast MT
across northern ND, northern MN, and the northern shores of the
Upper Peninsula. The MN Arrowhead sports the highest odds of
receiving over a foot of snow with WPC probabilities showing
modertae-to-high values of 50-70%. There are even some low-to-
moderate chances (20-50%) for localized amounts surpassing 18" in
the Arrowhead through Wednesday. The WSSI shows a large swath of
Minor to Moderate Impacts in these areas between Tuesday and
Wednesday, showing an extensive part of the North Central U.S.
will be subjected to hazardous travel conditions starting Tuesday
and lasting through Wednesday.


...Northeast...
Day 3...

The strong low-level WAA ahead of the powerful storm system in the
Upper Midwest will stretch as far east as the Northeast on
Wednesday. High pressure over southern Canada is providing enough
cold air to support wintry precipitation, although precipitation
type will largely depend upon the depth of the sub-freezing
temperatures within the boundary layer. Guidance is coming into
decent agreement on a narrow tongue of QPF >0.5" over much of
Upstate NY and as far east as the Berkshires and Green Mountains.
However, guidance disagrees on the placement of this band of heavy
QPF. The farther south the band is, the farther away from the
source of the colder air it becomes, making a combination of snow,
freezing rain, and event potential plain rain in lower elevation
areas. However, farther north solutions would place the band of QPF
over the Adirondacks and Green Mountains, which would favor
heavier mountain snow there. Then there is the conundrum of
precipitation rates. While rates may start off heavy via strong
850mb FGEN, as the storm weakens over the Upper Midwest on
Wednesday so does the influx of WAA, leading to frontolysis aloft
that would weaken low- level forcing and reduce the dynamic cooling
aloft to support periods of heavy snow.

This is all to say that there remains a fair amount of uncertainty
in the forecast. WPC probabilities are indicating the Adirondacks,
Green, and White Mountains have low-to-moderate chances (30-50%)
for snowfall totals >4" through Wednesday night. Given the
uncertainty in the position of the heaviest QPF and lingering
questions regarding low-level thermal profiles, areas
with elevations over 1,000ft would be most favored to see some
accumulating snowfall on Wednesday. The Champlain and Upper Hudson
Valleys would likely reside just far enough north to support
measurable snowfall, as evident in WPC's probabilistic guidance
that highlights moderate chances (40-60%) for snowfall totals >1"
on Wednesday. Lastly, some minor ice accumulations are possible as
far south as the Lower Hudson Valley and southern New England with probabilities showing low-to-moderate chances (20-40%) for at least one-hundreth of and inch of ice accretion on Wednesday.


Mullinax




$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 161949
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
249 PM EST Mon Feb 16 2026

Valid 00Z Tue Feb 17 2026 - 00Z Fri Feb 20 2026


...Pacific & Interior Northwest...
Days 1-3...

An active period of winter weather expected this week across the
Pacific and Interior Northwest as repeated shortwaves dive through a
longwave trough entrenched across the region.

The period begins with increasing southerly mid-level flow
downstream of the lead shortwave which will be digging along the
British Columbia coast. This shortwave will continue to expand
southward, with the trough axis finally moving onshore WA/OR Tuesday
night. This impulse will continue to track eastward into the Great
Basin and Northern Rockies on Wednesday, with a secondary shortwave
moving onshore immediately in its wake. This mid-level evolution
will push 500mb heights down below the 0.5 climatological percentile
tonight through Wednesday morning, leading to snow levels for which
the NBM suggests will fall below 1000 ft as far as northern CA, with
the 10th percentile (which may be a better proxy due to steep lapse
rates beneath the cold core trough aloft) dropping to the surface
across most of the area. While the heaviest precipitation is
expected within surges of WAA D1 and D3, this could result in the
first light snowfall accumulations down to the valley floors and
lowlands of WA and OR.

For D1, the heaviest precipitation is expected across OR and into
ID, as well as the southern WA Cascades. Here, the IVT will maximize
within the broad WAA plume and within broad mid-level
divergence/height falls downstream of the lead shortwave trough.
Additionally, S/SW flow will impinge favorably into the Cascades for
upslope enhancement, with snow levels falling well below pass
levels, including potentially even to I-5 through the Willamette
Valley. The heaviest snow is expected above 2,000 ft, where WPC
probabilities are high (>70%) D1 and low (30%) D2 for 4+ inches each
day, leading to locally more than 12 inches of snowfall through
00Z/Thursday. This will create hazardous travel, especially across
Santiam, Willamette, and Siskiyou Passes. Light snow accumulations
are expected even onto the Coastal terrain of WA/OR where there
exists a 30-50% chance of at least 2 inches.

A brief break in precipitation is expected much of D2 before the
second shortwave approaches with renewed ascent and moisture
spreading into the area. A period of renewed snow is likely,
especially across the WA/OR Cascades and surrounding lowlands as
snow levels again fall below 500 ft. WPC probabilities for at least
1 inch of snow reach 30% even into the Portland, OR metro area and
surrounding Seattle, WA, with an additional 6+ inches of snowfall
likely (70% chance) across the southern WA and most of the OR
Cascades.


...California...
Days 1-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges this week...

A series of potent Pacific storm systems are working together to
direct copious amounts of moisture at the mountain ranges of the
"Golden State". While heavy snow has been unfolding in the
Siskiyou, Shasta, Trinity, and Salmon mountains of northern CA
since Sunday, very heavy snowfall has been ongoing today along the
Sierra Nevada with snow levels currently between 5,000 and
6,000ft. Tonight, the snow levels will drop precipitously to then
falling to as low as 2,500ft by Tuesday morning in the northern
Sierra, and 4,000 ft for the southern Sierra Nevada. Snowfall rates
between 1-2"/hr will be common with some instances of >3"/hr
snowfall rates in the central and southern Sierra Nevada. Heavy
snow will continue through tonight in the Transverse Ranges above
6,000ft. This first disturbance is the result of a strong shortwave
trough that will be pivoting east into California through this
evening. By Tuesday morning that upper level energy will be well
into the Intermountain west, through upsloping and a surface trough
will keep higher elevation snow going through tonight, albeit with
decreasing intensity.

On Tuesday, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second, arguably stronger
upper level low dives south along the West Coast, closely following
the first. This will spike onshore flow and additional moisture
supply on the southern and eastern flanks of the upper low. Renewed
heavy snow will start out across the northern California ranges
Tuesday morning, then spread south down the Sierra Nevada from
Tuesday afternoon through Tuesday night. Once again, 1-2 inch/hour
rates will be common with 3-4 inch/hour rates locally not out of
the question. Snow levels will continue to fall to around 1,000 ft
in far northern California (including the northern coastal range)
Tuesday night, around 2,500ft in the Sierra Nevada, and between
4,000 and 5,000 ft into the Transverse Ranges. Snow will continue
to fall across California's mountain ranges trough Wednesday as yet
another 500mb shortwave trough west of WA continues to sustain
what feels like an endless supply of Pacific moisture into the
Golden State. However, during the day Wednesday snowfall rates
could diminish in most of the mountains down to light snow or even
flurries at times. With the longwave trough overhead, snow levels
could creep down as low as 1,000ft in central CA and may support
minor accumulations down to 1,000ft.

On Thursday a pair of shortwaves, both moving SSE, but one
impacting the Northern California ranges, and the other following
the previous disturbances hugging the coast until it turns inland
over Southern California, will keep moderate snow ongoing along
most of California's ranges. Rates will not be quite as heavy on
Thursday as on previous days. Snow levels will fall in the
Transverse Ranges to as low as 3,500 feet Thursday morning, while
staying between 1,500 and 2,500 feet from the Sierra Nevada north.

California's mountain ranges welcome the snow, although it will
come down fast and furious through mid-week. Through the end of
this discussion's timeframe (00Z Fri), snowfall will be measured
in feet above 4,000ft along the Sierra Nevada. WPC probabilities
show high chances (>90%) for >30" of snow along Donner Pass through
00Z Friday and more snow still to come. The WSSI shows a large
swath of Extreme Impacts (Substantial disruptions to daily life;
extremely dangerous travel or impossible driving conditions,
extensive closures) for elevations generally above 5,000ft,
although some Major impacts as low as 4,000ft are possible. Major
to locally Extreme impacts are showing up in the peaks of the San
Gabriel and San Bernadino mountains, with mostly Moderate-to-Major
Impacts (increasingly more disruptive to travel jumping from
Moderate to Major). There are also likely to be some Major impacts
in the Coastal Range of northwest CA above 2,000ft. Note that there
are Minor to locally Moderate Impacts expected along I-5 around
Mount Shasta, signifying potential travel delays for I-5 in the
more elevated terrain of northern CA.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West this week that badly need the
boost in snowpack. With a lack of a frigid airmass ahead of this
healthy moisture source, the bulk of the heavy snow will be largely
confined to many of the taller mountain peaks. The heaviest
snowfall on Monday will reside in the Blue, Sawtooth, Wind River,
Uinta, and as far south as Mt. Charleston and the Mogollon Rim. WPC
72-hour probabilities are high (>70%) for snowfall totals >12" in
these mountain ranges through Thursday afternoon.

On Tuesday, the highly anomalous upper-low off the Pacific NW coast
will help to usher the initial upper low over southern CA east into
the Intermountain West, causing widespread height falls and a
larger plume of Pacific moisture to pass over the Rockies. The
potent closed low then heads inland over the interior NW and
northern Rockies on Wednesday while opening up into a trough,
prompting snow levels to crash and most valleys are likely to see
at least a coating of snow. Still, the lack of a frigid airmass at
the surface will keep the bulk of the heavy snow in the mountains
with ranges such as the Wasatch, Bear River, Tetons, Uinta, Wind
River, Mogollon Rim, and CO Rockies seeing anywhere from 1-2 feet
of snow. Expect Minor to Moderate Impacts, per the WSSI, with
travel over passes from the Lewis Range and Bitterroots to as far
south as the Mogollon Rim likely to contend with hazardous travel
conditions.

By Thursday, much of the Intermountain West will be in a lull
between storm systems, as the next in the series of shortwaves
moves across California. Some snow will spill over into much of
Nevada, while areas further east see the snow stop completely
during the day. Snow with the shortwave over California moves
across the Four Corners into Thursday night and Friday.


...Northern Plains & Upper Great Lakes...
Days 2-3...

A shortwave emerging form the Great Basin will track rapidly
northeast Tuesday, reaching the Dakotas Tuesday evening while
amplifying. As this trough becomes negatively tilted and expands
across the Northern Plains/Upper Midwest, it will interact with the
LFQ of a strengthening subtropical jet streak arcing from the Desert
Southwest to the Great Lakes, to support surface cyclogenesis
Tuesday evening. This low is then expected to move very slowly
through Wednesday before gradually filling over the Western Great
Lakes Thursday night.

As this low tracks slowly eastward, it will interact with impressive
IVT surging above the 99th climatological percentile into Minnesota,
with the accompanying moisture and theta-e ridge axis then wrapping cyclonically around the system and lifting into a pronounced TROWAL.
The associated synoptic lift, aided by increasing WAA, will expand precipitation across the northern tier of the CONUS from far eastern
MT through the western Great Lakes, with periods of heavy snow
likely as strongly sloped FGEN driving omega into the TROWAL
supports heavy precipitation rates. The most impressive ascent
appears to intersect the DGZ, so despite this being subjectively
elevated (nearing 500mb) it will support heavy snow rates and
dynamic cooling into a column that is initially too warm to support
snow. However, once precipitation changes to snow, it will become
heavy, supported by the WAA/fgen beneath the TROWAL and accompanying
CSI evident in cross-sections, to support rates that will likely
exceed 1"/hr at times (60-90% chance). These intense rates will be
accompanied by strong and gusty winds, resulting in widespread
moderate impacts (30-60% chance) from ND through the Arrowhead of
MN. Here, there is a high probability (>70% chance) of more than 4
inches of snowfall accumulating, with locally 8-10 inches possible.
Some even higher totals, exceeding 12 inches, may occur (30-50%
chance) along the Arrowhead of MN where upslope flow with lake-
enhanced moisture will combine to bring greater snowfall and
resulting impacts.

Additionally, with the pronounced WAA rotating around the surface
low, an area of freezing rain is also expected, especially from near
Duluth, MN eastward across northern WI and into northern MI where
the warm nose will be most prevalent, but low-level easterly flow
will maintain sub-freezing surface temperatures. In this area, WPC probabilities are moderate (50-70%) for at least 0.1" of ice, with
locally more than 0.25" possible, most likely across the northern
L.P. of MI.


...Northeast...
Days 2-3...

A strong surface low moving slowly across the Dakotas/Minnesota
Wednesday will remain entrenched within an elongated mid-level
trough extending into the Mid-Atlantic states. Vorticity lobes
downstream of this wave will spread northeast from the Mid-Atlantic
states into the Northeast, before getting sheared rapidly to the
east as mid-level flow becomes strongly confluent south of secondary
shortwave energy crossing Maine and Nova Scotia. The resultant mid-
level PVA and divergence will overlap with a narrow ribbon of
impressive low-level WAA to produce a stripe of heavy precipitation
from Upstate NY through southern/central New England.

This precipitation will expand eastward from the Great Lakes
Wednesday morning, exiting off the New England coast by Thursday
morning. While the guidance continues to feature some latitudinal
variability within what will likely be a narrow corridor of
precipitation, the evolution of the upper jet streak (initially
downstream a poleward arcing, but becoming more zonal and stretch
south of the precipitation) will force a quasi-laterally translating
band of precipitation, but with slow weakening of intensity through
Thursday morning. This is reflected by just modest fgen in the 925-
850mb layer, and although some fgen may increase late as a surface
wave develops offshore leading to more pronounced low-level
convergence over New England, this will occur as the column dries
from the top down, limiting moist ascent, so most of the
precipitation should remain of modest intensity, with locally higher
rates possible, especially Wednesday, during the period of most
impressive WAA.

Thermally, the antecedent column is marginal to support wintry
precipitation, and it appears any significant snowfall accumulations
will be confined to higher elevations above 1,000 ft, or where the
most intense dynamic cooling can overwhelm the above-freezing low-
levels. This is most likely from Upstate NY into western VT where
conditional instability into a DGZ of modest depth is possible (30%
chance from the SREF). This will support briefly heavier snowfall
rates, which could linger as the band of precipitation tracks
along its long axis. This is reflected by WPC probabilities that
reach as high as 10-30% for 4+ inches of snow, especially in the
Adirondacks and Greens, with moderate probabilities for 2+ inches
covering much of central New England and the northern half of
Upstate NY. It is important to note that the WSE mean snowfall for
much of this area lies well below the maximum values, so some
locally higher amounts are probable where any banding persists.
South of this axis of moderate to heavy snow, a corridor of icing
exceeding 0.1" is possible (10-30% chance) from the southern shore
of Lake Ontario through the capital region of NY near Albany.


...Central Plains...
Day 3...

The same shortwave that brings heavy snow to California Tuesday
night and spreads over much of the Intermountain West during the
day on Wednesday will eject out into the Plains starting Wednesday
night. This will cause lee cyclogenesis over northern Colorado.
That low will then track east into Kansas, then turns northeast
into Iowa by Thursday evening. To the north and west of the low
track, chances for impactful snow have been increasing. While
there remains considerable uncertainty both in track and amounts
with this storm, agreement has been increasing. The swath of
heaviest snow, on the order of 4-6 inches, extends from far
southeast Montana through a portion of Wyoming and South Dakota,
and into north-central Nebraska. WPC 72-hour probabilities are
moderate (40-60%) for 4 inches of snow in this region Wednesday
night into Thursday.



Weiss/Wegman




$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 161954
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
254 PM EST Mon Feb 16 2026

Valid 00Z Tue Feb 17 2026 - 00Z Fri Feb 20 2026


...Pacific & Interior Northwest...
Days 1-3...

An active period of winter weather expected this week across the
Pacific and Interior Northwest as repeated shortwaves dive through a
longwave trough entrenched across the region.

The period begins with increasing southerly mid-level flow
downstream of the lead shortwave which will be digging along the
British Columbia coast. This shortwave will continue to expand
southward, with the trough axis finally moving onshore WA/OR Tuesday
night. This impulse will continue to track eastward into the Great
Basin and Northern Rockies on Wednesday, with a secondary shortwave
moving onshore immediately in its wake. This mid-level evolution
will push 500mb heights down below the 0.5 climatological percentile
tonight through Wednesday morning, leading to snow levels for which
the NBM suggests will fall below 1000 ft as far as northern CA, with
the 10th percentile (which may be a better proxy due to steep lapse
rates beneath the cold core trough aloft) dropping to the surface
across most of the area. While the heaviest precipitation is
expected within surges of WAA D1 and D3, this could result in the
first light snowfall accumulations down to the valley floors and
lowlands of WA and OR.

For D1, the heaviest precipitation is expected across OR and into
ID, as well as the southern WA Cascades. Here, the IVT will maximize
within the broad WAA plume and within broad mid-level
divergence/height falls downstream of the lead shortwave trough.
Additionally, S/SW flow will impinge favorably into the Cascades for
upslope enhancement, with snow levels falling well below pass
levels, including potentially even to I-5 through the Willamette
Valley. The heaviest snow is expected above 2,000 ft, where WPC
probabilities are high (>70%) D1 and low (30%) D2 for 4+ inches each
day, leading to locally more than 12 inches of snowfall through
00Z/Thursday. This will create hazardous travel, especially across
Santiam, Willamette, and Siskiyou Passes. Light snow accumulations
are expected even onto the Coastal terrain of WA/OR where there
exists a 30-50% chance of at least 2 inches.

A brief break in precipitation is expected much of D2 before the
second shortwave approaches with renewed ascent and moisture
spreading into the area. A period of renewed snow is likely,
especially across the WA/OR Cascades and surrounding lowlands as
snow levels again fall below 500 ft. WPC probabilities for at least
1 inch of snow reach 30% even into the Portland, OR metro area and
surrounding Seattle, WA, with an additional 6+ inches of snowfall
likely (70% chance) across the southern WA and most of the OR
Cascades.


...California...
Days 1-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges this week...

A series of potent Pacific storm systems are working together to
direct copious amounts of moisture at the mountain ranges of the
"Golden State". While heavy snow has been unfolding in the
Siskiyou, Shasta, Trinity, and Salmon mountains of northern CA
since Sunday, very heavy snowfall has been ongoing today along the
Sierra Nevada with snow levels currently between 5,000 and
6,000ft. Tonight, the snow levels will drop precipitously to then
falling to as low as 2,500ft by Tuesday morning in the northern
Sierra, and 4,000 ft for the southern Sierra Nevada. Snowfall rates
between 1-2"/hr will be common with some instances of >3"/hr
snowfall rates in the central and southern Sierra Nevada. Heavy
snow will continue through tonight in the Transverse Ranges above
6,000ft. This first disturbance is the result of a strong shortwave
trough that will be pivoting east into California through this
evening. By Tuesday morning that upper level energy will be well
into the Intermountain west, through upsloping and a surface trough
will keep higher elevation snow going through tonight, albeit with
decreasing intensity.

On Tuesday, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second, arguably stronger
upper level low dives south along the West Coast, closely following
the first. This will spike onshore flow and additional moisture
supply on the southern and eastern flanks of the upper low. Renewed
heavy snow will start out across the northern California ranges
Tuesday morning, then spread south down the Sierra Nevada from
Tuesday afternoon through Tuesday night. Once again, 1-2 inch/hour
rates will be common with 3-4 inch/hour rates locally not out of
the question. Snow levels will continue to fall to around 1,000 ft
in far northern California (including the northern coastal range)
Tuesday night, around 2,500ft in the Sierra Nevada, and between
4,000 and 5,000 ft into the Transverse Ranges. Snow will continue
to fall across California's mountain ranges trough Wednesday as yet
another 500mb shortwave trough west of WA continues to sustain
what feels like an endless supply of Pacific moisture into the
Golden State. However, during the day Wednesday snowfall rates
could diminish in most of the mountains down to light snow or even
flurries at times. With the longwave trough overhead, snow levels
could creep down as low as 1,000ft in central CA and may support
minor accumulations down to 1,000ft.

On Thursday a pair of shortwaves, both moving SSE, but one
impacting the Northern California ranges, and the other following
the previous disturbances hugging the coast until it turns inland
over Southern California, will keep moderate snow ongoing along
most of California's ranges. Rates will not be quite as heavy on
Thursday as on previous days. Snow levels will fall in the
Transverse Ranges to as low as 3,500 feet Thursday morning, while
staying between 1,500 and 2,500 feet from the Sierra Nevada north.

California's mountain ranges welcome the snow, although it will
come down fast and furious through mid-week. Through the end of
this discussion's timeframe (00Z Fri), snowfall will be measured
in feet above 4,000ft along the Sierra Nevada. WPC probabilities
show high chances (>90%) for >30" of snow along Donner Pass through
00Z Friday and more snow still to come. The WSSI shows a large
swath of Extreme Impacts (Substantial disruptions to daily life;
extremely dangerous travel or impossible driving conditions,
extensive closures) for elevations generally above 5,000ft,
although some Major impacts as low as 4,000ft are possible. Major
to locally Extreme impacts are showing up in the peaks of the San
Gabriel and San Bernadino mountains, with mostly Moderate-to-Major
Impacts (increasingly more disruptive to travel jumping from
Moderate to Major). There are also likely to be some Major impacts
in the Coastal Range of northwest CA above 2,000ft. Note that there
are Minor to locally Moderate Impacts expected along I-5 around
Mount Shasta, signifying potential travel delays for I-5 in the
more elevated terrain of northern CA.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West this week that badly need the
boost in snowpack. With a lack of a frigid airmass ahead of this
healthy moisture source, the bulk of the heavy snow will be largely
confined to many of the taller mountain peaks. The heaviest
snowfall on Monday will reside in the Blue, Sawtooth, Wind River,
Uinta, and as far south as Mt. Charleston and the Mogollon Rim. WPC
72-hour probabilities are high (>70%) for snowfall totals >12" in
these mountain ranges through Thursday afternoon.

On Tuesday, the highly anomalous upper-low off the Pacific NW coast
will help to usher the initial upper low over southern CA east into
the Intermountain West, causing widespread height falls and a
larger plume of Pacific moisture to pass over the Rockies. The
potent closed low then heads inland over the interior NW and
northern Rockies on Wednesday while opening up into a trough,
prompting snow levels to crash and most valleys are likely to see
at least a coating of snow. Still, the lack of a frigid airmass at
the surface will keep the bulk of the heavy snow in the mountains
with ranges such as the Wasatch, Bear River, Tetons, Uinta, Wind
River, Mogollon Rim, and CO Rockies seeing anywhere from 1-2 feet
of snow. Expect Minor to Moderate Impacts, per the WSSI, with
travel over passes from the Lewis Range and Bitterroots to as far
south as the Mogollon Rim likely to contend with hazardous travel
conditions.

By Thursday, much of the Intermountain West will be in a lull
between storm systems, as the next in the series of shortwaves
moves across California. Some snow will spill over into much of
Nevada, while areas further east see the snow stop completely
during the day. Snow with the shortwave over California moves
across the Four Corners into Thursday night and Friday.


...Northern Plains & Upper Great Lakes...
Days 2-3...

A shortwave emerging form the Great Basin will track rapidly
northeast Tuesday, reaching the Dakotas Tuesday evening while
amplifying. As this trough becomes negatively tilted and expands
across the Northern Plains/Upper Midwest, it will interact with the
LFQ of a strengthening subtropical jet streak arcing from the Desert
Southwest to the Great Lakes, to support surface cyclogenesis
Tuesday evening. This low is then expected to move very slowly
through Wednesday before gradually filling over the Western Great
Lakes Thursday night.

As this low tracks slowly eastward, it will interact with impressive
IVT surging above the 99th climatological percentile into Minnesota,
with the accompanying moisture and theta-e ridge axis then wrapping cyclonically around the system and lifting into a pronounced TROWAL.
The associated synoptic lift, aided by increasing WAA, will expand precipitation across the northern tier of the CONUS from far eastern
MT through the western Great Lakes, with periods of heavy snow
likely as strongly sloped FGEN driving omega into the TROWAL
supports heavy precipitation rates. The most impressive ascent
appears to intersect the DGZ, so despite this being subjectively
elevated (nearing 500mb) it will support heavy snow rates and
dynamic cooling into a column that is initially too warm to support
snow. However, once precipitation changes to snow, it will become
heavy, supported by the WAA/fgen beneath the TROWAL and accompanying
CSI evident in cross-sections, to support rates that will likely
exceed 1"/hr at times (60-90% chance). These intense rates will be
accompanied by strong and gusty winds, resulting in widespread
moderate impacts (30-60% chance) from ND through the Arrowhead of
MN. Here, there is a high probability (>70% chance) of more than 4
inches of snowfall accumulating, with locally 8-10 inches possible.
Some even higher totals, exceeding 12 inches, may occur (30-50%
chance) along the Arrowhead of MN where upslope flow with lake-
enhanced moisture will combine to bring greater snowfall and
resulting impacts.

Additionally, with the pronounced WAA rotating around the surface
low, an area of freezing rain is also expected, especially from near
Duluth, MN eastward across northern WI and into northern MI where
the warm nose will be most prevalent, but low-level easterly flow
will maintain sub-freezing surface temperatures. In this area, WPC probabilities are moderate (50-70%) for at least 0.1" of ice, with
locally more than 0.25" possible, most likely across the northern
L.P. of MI.


...Northeast...
Days 2-3...

A strong surface low moving slowly across the Dakotas/Minnesota
Wednesday will remain entrenched within an elongated mid-level
trough extending into the Mid-Atlantic states. Vorticity lobes
downstream of this wave will spread northeast from the Mid-Atlantic
states into the Northeast, before getting sheared rapidly to the
east as mid-level flow becomes strongly confluent south of secondary
shortwave energy crossing Maine and Nova Scotia. The resultant mid-
level PVA and divergence will overlap with a narrow ribbon of
impressive low-level WAA to produce a stripe of heavy precipitation
from Upstate NY through southern/central New England.

This precipitation will expand eastward from the Great Lakes
Wednesday morning, exiting off the New England coast by Thursday
morning. While the guidance continues to feature some latitudinal
variability within what will likely be a narrow corridor of
precipitation, the evolution of the upper jet streak (initially
downstream a poleward arcing, but becoming more zonal and stretch
south of the precipitation) will force a quasi-laterally translating
band of precipitation, but with slow weakening of intensity through
Thursday morning. This is reflected by just modest fgen in the 925-
850mb layer, and although some fgen may increase late as a surface
wave develops offshore leading to more pronounced low-level
convergence over New England, this will occur as the column dries
from the top down, limiting moist ascent, so most of the
precipitation should remain of modest intensity, with locally higher
rates possible, especially Wednesday, during the period of most
impressive WAA.

Thermally, the antecedent column is marginal to support wintry
precipitation, and it appears any significant snowfall accumulations
will be confined to higher elevations above 1,000 ft, or where the
most intense dynamic cooling can overwhelm the above-freezing low-
levels. This is most likely from Upstate NY into western VT where
conditional instability into a DGZ of modest depth is possible (30%
chance from the SREF). This will support briefly heavier snowfall
rates, which could linger as the band of precipitation tracks
along its long axis. This is reflected by WPC probabilities that
reach as high as 10-30% for 4+ inches of snow, especially in the
Adirondacks and Greens, with moderate probabilities for 2+ inches
covering much of central New England and the northern half of
Upstate NY. It is important to note that the WSE mean snowfall for
much of this area lies well below the maximum values, so some
locally higher amounts are probable where any banding persists.
South of this axis of moderate to heavy snow, a corridor of icing
exceeding 0.1" is possible (10-30% chance) from the southern shore
of Lake Ontario through the capital region of NY near Albany.


...Central Plains...
Day 3...

The same shortwave that brings heavy snow to California Tuesday
night and spreads over much of the Intermountain West during the
day on Wednesday will eject out into the Plains starting Wednesday
night. This will cause lee cyclogenesis over northern Colorado.
That low will then track east into Kansas, then turns northeast
into Iowa by Thursday evening. To the north and west of the low
track, chances for impactful snow have been increasing. While
there remains considerable uncertainty both in track and amounts
with this storm, agreement has been increasing. The swath of
heaviest snow, on the order of 4-6 inches, extends from far
southeast Montana through a portion of Wyoming and South Dakota,
and into north-central Nebraska. WPC 72-hour probabilities are
moderate (40-60%) for 4 inches of snow in this region Wednesday
night into Thursday.



Weiss/Wegman



$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 161958
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
258 PM EST Mon Feb 16 2026

Valid 00Z Tue Feb 17 2026 - 00Z Fri Feb 20 2026


...Pacific & Interior Northwest...
Days 1-3...

An active period of winter weather expected this week across the
Pacific and Interior Northwest as repeated shortwaves dive through a
longwave trough entrenched across the region.

The period begins with increasing southerly mid-level flow downstream
of the lead shortwave which will be digging along the British
Columbia coast. This shortwave will continue to expand southward, with
the trough axis finally moving onshore WA/OR Tuesday night. This
impulse will continue to track eastward into the Great Basin and
Northern Rockies on Wednesday, with a secondary shortwave moving
onshore immediately in its wake. This mid-level evolution will push
500mb heights down below the 0.5 climatological percentile tonight
through Wednesday morning, leading to snow levels for which the NBM
suggests will fall below 1000 ft as far as northern CA, with the 10th percentile (which may be a better proxy due to steep lapse rates
beneath the cold core trough aloft) dropping to the surface across
most of the area. While the heaviest precipitation is expected within
surges of WAA D1 and D3, this could result in the first light snowfall accumulations down to the valley floors and lowlands of WA and OR.

For D1, the heaviest precipitation is expected across OR and into
ID, as well as the southern WA Cascades. Here, the IVT will maximize
within the broad WAA plume and within broad mid-level
divergence/height falls downstream of the lead shortwave trough.
Additionally, S/SW flow will impinge favorably into the Cascades for
upslope enhancement, with snow levels falling well below pass levels,
including potentially even to I-5 through the Willamette Valley. The
heaviest snow is expected above 2,000 ft, where WPC probabilities are
high (>70%) D1 and low (30%) D2 for 4+ inches each day, leading to
locally more than 12 inches of snowfall through 00Z/Thursday. This
will create hazardous travel, especially across Santiam, Willamette,
and Siskiyou Passes. Light snow accumulations are expected even onto
the Coastal terrain of WA/OR where there exists a 30-50% chance of at
least 2 inches.

A brief break in precipitation is expected much of D2 before the
second shortwave approaches with renewed ascent and moisture spreading
into the area. A period of renewed snow is likely, especially across
the WA/OR Cascades and surrounding lowlands as snow levels again fall
below 500 ft. WPC probabilities for at least 1 inch of snow reach 30%
even into the Portland, OR metro area and surrounding Seattle, WA,
with an additional 6+ inches of snowfall likely (70% chance) across
the southern WA and most of the OR Cascades.


...California...
Days 1-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges this week...

A series of potent Pacific storm systems are working together to
direct copious amounts of moisture at the mountain ranges of the
"Golden State". While heavy snow has been unfolding in the
Siskiyou, Shasta, Trinity, and Salmon mountains of northern CA
since Sunday, very heavy snowfall has been ongoing today along the
Sierra Nevada with snow levels currently between 5,000 and
6,000ft. Tonight, the snow levels will drop precipitously to then
falling to as low as 2,500ft by Tuesday morning in the northern
Sierra, and 4,000 ft for the southern Sierra Nevada. Snowfall rates
between 1-2"/hr will be common with some instances of >3"/hr
snowfall rates in the central and southern Sierra Nevada. Heavy
snow will continue through tonight in the Transverse Ranges above
6,000ft. This first disturbance is the result of a strong shortwave
trough that will be pivoting east into California through this
evening. By Tuesday morning that upper level energy will be well
into the Intermountain west, through upsloping and a surface trough
will keep higher elevation snow going through tonight, albeit with
decreasing intensity.

On Tuesday, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second, arguably stronger
upper level low dives south along the West Coast, closely following
the first. This will spike onshore flow and additional moisture
supply on the southern and eastern flanks of the upper low. Renewed
heavy snow will start out across the northern California ranges
Tuesday morning, then spread south down the Sierra Nevada from
Tuesday afternoon through Tuesday night. Once again, 1-2 inch/hour
rates will be common with 3-4 inch/hour rates locally not out of
the question. Snow levels will continue to fall to around 1,000 ft
in far northern California (including the northern coastal range)
Tuesday night, around 2,500ft in the Sierra Nevada, and between
4,000 and 5,000 ft into the Transverse Ranges. Snow will continue
to fall across California's mountain ranges trough Wednesday as yet
another 500mb shortwave trough west of WA continues to sustain
what feels like an endless supply of Pacific moisture into the
Golden State. However, during the day Wednesday snowfall rates
could diminish in most of the mountains down to light snow or even
flurries at times. With the longwave trough overhead, snow levels
could creep down as low as 1,000ft in central CA and may support
minor accumulations down to 1,000ft.

On Thursday a pair of shortwaves, both moving SSE, but one
impacting the Northern California ranges, and the other following
the previous disturbances hugging the coast until it turns inland
over Southern California, will keep moderate snow ongoing along
most of California's ranges. Rates will not be quite as heavy on
Thursday as on previous days. Snow levels will fall in the
Transverse Ranges to as low as 3,500 feet Thursday morning, while
staying between 1,500 and 2,500 feet from the Sierra Nevada north.

California's mountain ranges welcome the snow, although it will
come down fast and furious through mid-week. Through the end of
this discussion's timeframe (00Z Fri), snowfall will be measured
in feet above 4,000ft along the Sierra Nevada. WPC probabilities
show high chances (>90%) for >30" of snow along Donner Pass through
00Z Friday and more snow still to come. The WSSI shows a large
swath of Extreme Impacts (Substantial disruptions to daily life;
extremely dangerous travel or impossible driving conditions,
extensive closures) for elevations generally above 5,000ft,
although some Major impacts as low as 4,000ft are possible. Major
to locally Extreme impacts are showing up in the peaks of the San
Gabriel and San Bernadino mountains, with mostly Moderate-to-Major
Impacts (increasingly more disruptive to travel jumping from
Moderate to Major). There are also likely to be some Major impacts
in the Coastal Range of northwest CA above 2,000ft. Note that there
are Minor to locally Moderate Impacts expected along I-5 around
Mount Shasta, signifying potential travel delays for I-5 in the
more elevated terrain of northern CA.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West this week that badly need the
boost in snowpack. With a lack of a frigid airmass ahead of this
healthy moisture source, the bulk of the heavy snow will be largely
confined to many of the taller mountain peaks. The heaviest
snowfall on Monday will reside in the Blue, Sawtooth, Wind River,
Uinta, and as far south as Mt. Charleston and the Mogollon Rim. WPC
72-hour probabilities are high (>70%) for snowfall totals >12" in
these mountain ranges through Thursday afternoon.

On Tuesday, the highly anomalous upper-low off the Pacific NW coast
will help to usher the initial upper low over southern CA east into
the Intermountain West, causing widespread height falls and a
larger plume of Pacific moisture to pass over the Rockies. The
potent closed low then heads inland over the interior NW and
northern Rockies on Wednesday while opening up into a trough,
prompting snow levels to crash and most valleys are likely to see at
least a coating of snow. Still, the lack of a frigid airmass at the
surface will keep the bulk of the heavy snow in the mountains with
ranges such as the Wasatch, Bear River, Tetons, Uinta, Wind River,
Mogollon Rim, and CO Rockies seeing anywhere from 1-2 feet of snow.
Expect Minor to Moderate Impacts, per the WSSI, with travel over
passes from the Lewis Range and Bitterroots to as far south as the
Mogollon Rim likely to contend with hazardous travel conditions.

By Thursday, much of the Intermountain West will be in a lull
between storm systems, as the next in the series of shortwaves
moves across California. Some snow will spill over into much of
Nevada, while areas further east see the snow stop completely
during the day. Snow with the shortwave over California moves
across the Four Corners into Thursday night and Friday.


...Northern Plains & Upper Great Lakes...
Days 2-3...

A shortwave emerging form the Great Basin will track rapidly
northeast Tuesday, reaching the Dakotas Tuesday evening while
amplifying. As this trough becomes negatively tilted and expands
across the Northern Plains/Upper Midwest, it will interact with the
LFQ of a strengthening subtropical jet streak arcing from the Desert
Southwest to the Great Lakes, to support surface cyclogenesis
Tuesday evening. This low is then expected to move very slowly
through Wednesday before gradually filling over the Western Great
Lakes Thursday night.

As this low tracks slowly eastward, it will interact with impressive
IVT surging above the 99th climatological percentile into Minnesota,
with the accompanying moisture and theta-e ridge axis then wrapping cyclonically around the system and lifting into a pronounced TROWAL.
The associated synoptic lift, aided by increasing WAA, will expand precipitation across the northern tier of the CONUS from far eastern
MT through the western Great Lakes, with periods of heavy snow likely
as strongly sloped FGEN driving omega into the TROWAL supports heavy precipitation rates. The most impressive ascent appears to intersect
the DGZ, so despite this being subjectively elevated (nearing
500mb) it will support heavy snow rates and dynamic cooling into a column
that is initially too warm to support snow. However, once precipitation
changes to snow, it will become heavy, supported by the WAA/fgen
beneath the TROWAL and accompanying CSI evident in cross- sections,
to support rates that will likely exceed 1"/hr at times (60-90%
chance). These intense rates will be accompanied by strong and
gusty winds, resulting in widespread moderate impacts (30-60%
chance) from ND through the Arrowhead of MN. Here, there is a high
probability (>70% chance) of more than 4 inches of snowfall accumulating,
with locally 8-10 inches possible. Some even higher totals,
exceeding 12 inches, may occur (30-50% chance) along the Arrowhead
of MN where upslope flow with lake- enhanced moisture will combine
to bring greater snowfall and resulting impacts.

Additionally, with the pronounced WAA rotating around the surface
low, an area of freezing rain is also expected, especially from near
Duluth, MN eastward across northern WI and into northern MI where the
warm nose will be most prevalent, but low-level easterly flow will
maintain sub-freezing surface temperatures. In this area, WPC
probabilities are moderate (50-70%) for at least 0.1" of ice, with
locally more than 0.25" possible, most likely across the northern
L.P. of MI.


...Northeast...
Days 2-3...

A strong surface low moving slowly across the Dakotas/Minnesota
Wednesday will remain entrenched within an elongated mid-level
trough extending into the Mid-Atlantic states. Vorticity lobes
downstream of this wave will spread northeast from the Mid-
Atlantic states into the Northeast, before getting sheared rapidly
to the east as mid-level flow becomes strongly confluent south of
secondary shortwave energy crossing Maine and Nova Scotia. The
resultant mid- level PVA and divergence will overlap with a narrow
ribbon of impressive low-level WAA to produce a stripe of heavy
precipitation from Upstate NY through southern/central New England.

This precipitation will expand eastward from the Great Lakes
Wednesday morning, exiting off the New England coast by Thursday
morning. While the guidance continues to feature some latitudinal
variability within what will likely be a narrow corridor of
precipitation, the evolution of the upper jet streak (initially
downstream a poleward arcing, but becoming more zonal and stretch
south of the precipitation) will force a quasi-laterally translating
band of precipitation, but with slow weakening of intensity through
Thursday morning. This is reflected by just modest fgen in the
925- 850mb layer, and although some fgen may increase late as a
surface wave develops offshore leading to more pronounced low-level
convergence over New England, this will occur as the column dries
from the top down, limiting moist ascent, so most of the
precipitation should remain of modest intensity, with locally
higher rates possible, especially Wednesday, during the period of
most impressive WAA.

Thermally, the antecedent column is marginal to support wintry
precipitation, and it appears any significant snowfall accumulations
will be confined to higher elevations above 1,000 ft, or where the
most intense dynamic cooling can overwhelm the above-freezing low-
levels. This is most likely from Upstate NY into western VT where
conditional instability into a DGZ of modest depth is possible (30%
chance from the SREF). This will support briefly heavier snowfall
rates, which could linger as the band of precipitation tracks
along its long axis. This is reflected by WPC probabilities that
reach as high as 10-30% for 4+ inches of snow, especially in the
Adirondacks and Greens, with moderate probabilities for 2+ inches
covering much of central New England and the northern half of
Upstate NY. It is important to note that the WSE mean snowfall for
much of this area lies well below the maximum values, so some
locally higher amounts are probable where any banding persists.
South of this axis of moderate to heavy snow, a corridor of icing
exceeding 0.1" is possible (10-30% chance) from the southern shore
of Lake Ontario through the capital region of NY near Albany.


...Central Plains...
Day 3...

The same shortwave that brings heavy snow to California Tuesday
night and spreads over much of the Intermountain West during the
day on Wednesday will eject out into the Plains starting Wednesday
night. This will cause lee cyclogenesis over northern Colorado.
That low will then track east into Kansas, then turns northeast
into Iowa by Thursday evening. To the north and west of the low
track, chances for impactful snow have been increasing. While there
remains considerable uncertainty both in track and amounts with
this storm, agreement has been increasing. The swath of heaviest
snow, on the order of 4-6 inches, extends from far southeast
Montana through a portion of Wyoming and South Dakota, and into
north-central Nebraska. WPC 72-hour probabilities are moderate
(40-60%) for 4 inches of snow in this region Wednesday night into
Thursday.



Weiss/Wegman






$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 162002
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
302 PM EST Mon Feb 16 2026

Valid 00Z Tue Feb 17 2026 - 00Z Fri Feb 20 2026


...Pacific & Interior Northwest...
Days 1-3...

An active period of winter weather expected this week across the
Pacific and Interior Northwest as repeated shortwaves dive through a
longwave trough entrenched across the region.

The period begins with increasing southerly mid-level flow
downstream of the lead shortwave which will be digging along the
British Columbia coast. This shortwave will continue to expand
southward, with the trough axis finally moving onshore WA/OR Tuesday
night. This impulse will continue to track eastward into the Great
Basin and Northern Rockies on Wednesday, with a secondary shortwave
moving onshore immediately in its wake. This mid-level evolution
will push 500mb heights down below the 0.5 climatological percentile
tonight through Wednesday morning, leading to snow levels for which
the NBM suggests will fall below 1000 ft as far as northern CA, with
the 10th percentile (which may be a better proxy due to steep lapse
rates beneath the cold core trough aloft) dropping to the surface
across most of the area. While the heaviest precipitation is
expected within surges of WAA D1 and D3, this could result in the
first light snowfall accumulations down to the valley floors and
lowlands of WA and OR.

For D1, the heaviest precipitation is expected across OR and into
ID, as well as the southern WA Cascades. Here, the IVT will maximize
within the broad WAA plume and within broad mid-level
divergence/height falls downstream of the lead shortwave trough.
Additionally, S/SW flow will impinge favorably into the Cascades for
upslope enhancement, with snow levels falling well below pass
levels, including potentially even to I-5 through the Willamette
Valley. The heaviest snow is expected above 2,000 ft, where WPC
probabilities are high (>70%) D1 and low (30%) D2 for 4+ inches each
day, leading to locally more than 12 inches of snowfall through
00Z/Thursday. This will create hazardous travel, especially across
Santiam, Willamette, and Siskiyou Passes. Light snow accumulations
are expected even onto the Coastal terrain of WA/OR where there
exists a 30-50% chance of at least 2 inches.

A brief break in precipitation is expected much of D2 before the
second shortwave approaches with renewed ascent and moisture
spreading into the area. A period of renewed snow is likely,
especially across the WA/OR Cascades and surrounding lowlands as
snow levels again fall below 500 ft. WPC probabilities for at least
1 inch of snow reach 30% even into the Portland, OR metro area and
surrouding Seattle, WA, with an additional 6+ inches of snowfall
likely (70% chance) across the southern WA and most of the OR
Cascades.


...California...
Days 1-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges this week...

A series of potent Pacific storm systems are working together to
direct copious amounts of moisture at the mountain ranges of the
"Golden State". While heavy snow has been unfolding in the
Siskiyou, Shasta, Trinity, and Salmon mountains of northern CA
since Sunday, very heavy snowfall has been ongoing today along the
Sierra Nevada with snow levels currently between 5,000 and
6,000ft. Tonight, the snow levels will drop precipitously to then
falling to as low as 2,500ft by Tuesday morning in the northern
Sierra, and 4,000 ft for the southern Sierra Nevada. Snowfall rates
between 1-2"/hr will be common with some instances of >3"/hr
snowfall rates in the central and southern Sierra Nevada. Heavy
snow will continue through tonight in the Transverse Ranges above
6,000ft. This first disturbance is the result of a strong shortwave
trough that will be pivoting east into California through this
evening. By Tuesday morning that upper level energy will be well
into the Intermountain west, through upsloping and a surface trough
will keep higher elevation snow going through tonight, albeit with
decreasing intensity.

On Tuesday, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second, arguably stronger
upper level low dives south along the West Coast, closely following
the first. This will spike onshore flow and additional moisture
supply on the southern and eastern flanks of the upper low. Renewed
heavy snow will start out across the northern California ranges
Tuesday morning, then spread south down the Sierra Nevada from
Tuesday afternoon through Tuesday night. Once again, 1-2 inch/hour
rates will be common with 3-4 inch/hour rates locally not out of
the question. Snow levels will continue to fall to around 1,000 ft
in far northern California (including the northern coastal range)
Tuesday night, around 2,500ft in the Sierra Nevada, and between
4,000 and 5,000 ft into the Transverse Ranges. Snow will continue
to fall across California's mountain ranges trough Wednesday as yet
another 500mb shortwave trough west of WA continues to sustain
what feels like an endless supply of Pacific moisture into the
Golden State. However, during the day Wednesday snowfall rates
could diminish in most of the mountains down to light snow or even
flurries at times. With the longwave trough overhead, snow levels
could creep down as low as 1,000ft in central CA and may support
minor accumulations down to 1,000ft.

On Thursday a pair of shortwaves, both moving SSE, but one
impacting the Northern California ranges, and the other following
the previous disturbances hugging the coast until it turns inland
over Southern California, will keep moderate snow ongoing along
most of California's ranges. Rates will not be quite as heavy on
Thursday as on previous days. Snow levels will fall in the
Transverse Ranges to as low as 3,500 feet Thursday morning, while
staying between 1,500 and 2,500 feet from the Sierra Nevada north.

California's mountain ranges welcome the snow, although it will
come down fast and furious through mid-week. Through the end of
this discussion's timeframe (00Z Fri), snowfall will be measured
in feet above 4,000ft along the Sierra Nevada. WPC probabilities
show high chances (>90%) for >30" of snow along Donner Pass through
00Z Friday and more snow still to come. The WSSI shows a large
swath of Extreme Impacts (Substantial disruptions to daily life;
extremely dangerous travel or impossible driving conditions,
extensive closures) for elevations generally above 5,000ft,
although some Major impacts as low as 4,000ft are possible. Major
to locally Extreme impacts are showing up in the peaks of the San
Gabriel and San Bernadino mountains, with mostly Moderate-to-Major
Impacts (increasingly more disruptive to travel jumping from
Moderate to Major). There are also likely to be some Major impacts
in the Coastal Range of northwest CA above 2,000ft. Note that there
are Minor to locally Moderate Impacts expected along I-5 around
Mount Shasta, signifying potential travel delays for I-5 in the
more elevated terrain of northern CA.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West this week that badly need the
boost in snowpack. With a lack of a frigid airmass ahead of this
healthy moisture source, the bulk of the heavy snow will be largely
confined to many of the taller mountain peaks. The heaviest
snowfall on Monday will reside in the Blue, Sawtooth, Wind River,
Uinta, and as far south as Mt. Charleston and the Mogollon Rim. WPC
72-hour probabilities are high (>70%) for snowfall totals >12" in
these mountain ranges through Thursday afternoon.

On Tuesday, the highly anomalous upper-low off the Pacific NW coast
will help to usher the initial upper low over southern CA east into
the Intermountain West, causing widespread height falls and a
larger plume of Pacific moisture to pass over the Rockies. The
potent closed low then heads inland over the interior NW and
northern Rockies on Wednesday while opening up into a trough,
prompting snow levels to crash and most valleys are likely to see at
least a coating of snow. Still, the lack of a frigid airmass at the
surface will keep the bulk of the heavy snow in the mountains with
ranges such as the Wasatch, Bear River, Tetons, Uinta, Wind River,
Mogollon Rim, and CO Rockies seeing anywhere from 1-2 feet of snow.
Expect Minor to Moderate Impacts, per the WSSI, with travel over
passes from the Lewis Range and Bitterroots to as far south as the
Mogollon Rim likely to contend with hazardous travel conditions.

By Thursday, much of the Intermountain West will be in a lull
between storm systems, as the next in the series of shortwaves
moves across California. Some snow will spill over into much of
Nevada, while areas further east see the snow stop completely
during the day. Snow with the shortwave over California moves
across the Four Corners into Thursday night and Friday.


...Northern Plains & Upper Great Lakes...
Days 2-3...

A shortwave emerging form the Great Basin will track rapidly
northeast Tuesday, reaching the Dakotas Tuesday evening while
amplifying. As this trough becomes negatively tilted and expands
across the Northern Plains/Upper Midwest, it will interact with the
LFQ of a strengthening subtropical jet streak arcing from the Desert
Southwest to the Great Lakes, to support surface cyclogensis Tuesday
evening. This low is then expected to move very slowly through
Wednesday before gradually filling over the Western Great Lakes
Thursday night.

As this low tracks slowly eastward, it will interact with impressive
IVT surging above the 99th climatological percentile into Minnesota,
with the accompanying moisture and theta-e ridge axis then wrapping cyclonically around the system and lifting into a pronounced TROWAL.
The associated synoptic lift, aided by increasing WAA, will expand precipitation across the northern tier of the CONUS from far eastern
MT through the western Great Lakes, with periods of heavy snow
likely as strongly sloped FGEN driving omega into the TROWAL
supports heavy preciptiation rates. The most impressive ascent
appears to intersect the DGZ, so despite this being subjectively
elevated (nearing 500mb) it will support heavy snow rates and
dynamic cooling into a column that is initially too warm to support
snow. However, once precipitation changes to snow, it will become
heavy, supported by the WAA/fgen beneath the TROWAL and accompanying
CSI evident in cross-sections, to support rates that will likely
exceed 1"/hr at times (60-90% chance). These intense rates will be
accompanied by strong and gusty winds, resulting in widespread
moderate impacts (30-60% chance) from ND through the Arrowhead of
MN. Here, there is a high probability (>70% chance) of more than 4
inches of snowfall accumulating, with locally 8-10 inches possible.
Some even higher totals, exceeding 12 inches, may occur (30-50%
chance) along the Arrowhead of MN where upslope flow with lake-
enhanced moisture will combine to bring greater snowfall and
resulting impacts.

Additionally, with the pronounced WAA rotating around the surface
low, an area of freezing rain is also expected, especially from near
Duluth, MN eastward across northern WI and into northern MI where
the warm nose will be most prevalant, but low-level easterly flow
will maintain sub-freezing surface temperatures. In this area, WPC probabilities are moderate (50-70%) for at least 0.1" of ice, with
locally more than 0.25" possible, most likely across the northern
L.P. of MI.


...Northeast...
Days 2-3...

A strong surface low moving slowly across the Dakotas/Minnesota
Wednesday will remain entrenched within an elongated mid-level
trough extending into the Mid-Atlantic states. Vorticity lobes
downstream of this wave will spread northeast from the Mid-Atlantic
states into the Northeast, before getting sheared rapidly to the
east as mid-level flow becomes strongly confluent south of secondary
shortwave energy crossing Maine and Nova Scotia. The resultant mid-
level PVA and divergence will overlap with a narrow ribbon of
impressive low-level WAA to produce a stripe of heavy precipitation
from Upstate NY through southern/central New England.

This precipitation will expand eastward from the Great Lakes
Wednesday morning, exiting off the New England coast by Thursday
morning. While the guidance continues to feature some latitudinal
variability within what will likely be a narrow corridor of
precipitation, the evolution of the upper jet streak (initially
downstream a poleward arcing, but becoming more zonal and stretch
south of the precipitation) will force a quasi-laterally translating
band of precipitation, but with slow weakening of intensity through
Thursday morning. This is reflected by just modest fgen in the 925-
850mb layer, and although some fgen may increase late as a surface
wave develops offshore leading to more pronounced low-level
convergence over New England, this will occur as the column dries
from the top down, limiting moist ascent, so most of the
precipitation should remain of modest intensity, with locally higher
rates possible, especially Wednesday, during the period of most
impressive WAA.

Thermally, the antecedent column is marginal to support wintry
precipitation, and it appears any significant snowfall accumulations
will be confined to higher elevations above 1,000 ft, or where the
most intense dynamic cooling can overwhelm the above-freezing low-
levels. This is most likely from Upstate NY into western VT where
conditional instability into a DGZ of modest depth is possible (30%
chance from the SREF). This will support briefly heavier snowfall
rates, which could linger as the band of preciptation tracks along
its long axis. This is reflected by WPC probabilities that reach as
high as 10-30% for 4+ inches of snow, especially in the Adirondacks
and Greens, with moderate probabilities for 2+ inches covering much
of central New England and the northern half of Upstate NY. It is
important to note that the WSE mean snowfall for much of this area
lies well below the maximum values, so some locally higher amounts
are probable where any banding persists. South of this axis of
moderate to heavy snow, a corridor of icing exceeding 0.1" is
possible (10-30% chance) from the southern shore of Lake Ontario
through the capital region of NY near Albany.



Weiss/Wegman

$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 162008
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
308 PM EST Mon Feb 16 2026

Valid 00Z Tue Feb 17 2026 - 00Z Fri Feb 20 2026


...Pacific & Interior Northwest...
Days 1-3...

An active period of winter weather expected this week across the Pacific
and Interior Northwest as repeated shortwaves dive through a longwave
trough entrenched across the region.

The period begins with increasing southerly mid-level flow downstream
of the lead shortwave which will be digging along the British Columbia
coast. This shortwave will continue to expand southward, with the trough
axis finally moving onshore WA/OR Tuesday night. This impulse will continue
to track eastward into the Great Basin and Northern Rockies on Wednesday,
with a secondary shortwave moving onshore immediately in its wake. This mid-level evolution will push 500mb heights down below the 0.5 climatological percentile tonight through Wednesday morning, leading to snow levels for
which the NBM suggests will fall below 1000 ft as far as northern CA,
with the 10th percentile (which may be a better proxy due to steep lapse
rates beneath the cold core trough aloft) dropping to the surface across
most of the area. While the heaviest precipitation is expected within
surges of WAA D1 and D3, this could result in the first light snowfall accumulations down to the valley floors and lowlands of WA and OR.

For D1, the heaviest precipitation is expected across OR and into ID, as
well as the southern WA Cascades. Here, the IVT will maximize within the
broad WAA plume and within broad mid-level divergence/height falls downstream of the lead shortwave trough. Additionally, S/SW flow will impinge favorably into the Cascades for upslope enhancement, with snow levels falling well
below pass levels, including potentially even to I-5 through the Willamette Valley. The heaviest snow is expected above 2,000 ft, where WPC probabilities are high (>70%) D1 and low (30%) D2 for 4+ inches each day, leading to
locally more than 12 inches of snowfall through 00Z/Thursday. This will
create hazardous travel, especially across Santiam, Willamette, and Siskiyou Passes. Light snow accumulations are expected even onto the Coastal terrain
of WA/OR where there exists a 30-50% chance of at least 2 inches.

A brief break in precipitation is expected much of D2 before the second shortwave approaches with renewed ascent and moisture spreading into
the area. A period of renewed snow is likely, especially across the WA/OR Cascades and surrounding lowlands as snow levels again fall below 500
ft. WPC probabilities for at least 1 inch of snow reach 30% even into
the Portland, OR metro area and surrouding Seattle, WA, with an additional
6+ inches of snowfall likely (70% chance) across the southern WA and most
of the OR Cascades.


...California...
Days 1-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges this week...

A series of potent Pacific storm systems are working together to
direct copious amounts of moisture at the mountain ranges of the
"Golden State". While heavy snow has been unfolding in the
Siskiyou, Shasta, Trinity, and Salmon mountains of northern CA
since Sunday, very heavy snowfall has been ongoing today along the
Sierra Nevada with snow levels currently between 5,000 and
6,000ft. Tonight, the snow levels will drop precipitously to then
falling to as low as 2,500ft by Tuesday morning in the northern
Sierra, and 4,000 ft for the southern Sierra Nevada. Snowfall rates
between 1-2"/hr will be common with some instances of >3"/hr
snowfall rates in the central and southern Sierra Nevada. Heavy
snow will continue through tonight in the Transverse Ranges above
6,000ft. This first disturbance is the result of a strong shortwave
trough that will be pivoting east into California through this
evening. By Tuesday morning that upper level energy will be well
into the Intermountain west, through upsloping and a surface trough
will keep higher elevation snow going through tonight, albeit with
decreasing intensity.

On Tuesday, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second, arguably stronger
upper level low dives south along the West Coast, closely following
the first. This will spike onshore flow and additional moisture
supply on the southern and eastern flanks of the upper low. Renewed
heavy snow will start out across the northern California ranges
Tuesday morning, then spread south down the Sierra Nevada from
Tuesday afternoon through Tuesday night. Once again, 1-2 inch/hour
rates will be common with 3-4 inch/hour rates locally not out of
the question. Snow levels will continue to fall to around 1,000 ft
in far northern California (including the northern coastal range)
Tuesday night, around 2,500ft in the Sierra Nevada, and between
4,000 and 5,000 ft into the Transverse Ranges. Snow will continue
to fall across California's mountain ranges trough Wednesday as yet
another 500mb shortwave trough west of WA continues to sustain
what feels like an endless supply of Pacific moisture into the
Golden State. However, during the day Wednesday snowfall rates
could diminish in most of the mountains down to light snow or even
flurries at times. With the longwave trough overhead, snow levels
could creep down as low as 1,000ft in central CA and may support
minor accumulations down to 1,000ft.

On Thursday a pair of shortwaves, both moving SSE, but one
impacting the Northern California ranges, and the other following
the previous disturbances hugging the coast until it turns inland
over Southern California, will keep moderate snow ongoing along
most of California's ranges. Rates will not be quite as heavy on
Thursday as on previous days. Snow levels will fall in the
Transverse Ranges to as low as 3,500 feet Thursday morning, while
staying between 1,500 and 2,500 feet from the Sierra Nevada north.

California's mountain ranges welcome the snow, although it will
come down fast and furious through mid-week. Through the end of
this discussion's timeframe (00Z Fri), snowfall will be measured
in feet above 4,000ft along the Sierra Nevada. WPC probabilities
show high chances (>90%) for >30" of snow along Donner Pass through
00Z Friday and more snow still to come. The WSSI shows a large
swath of Extreme Impacts (Substantial disruptions to daily life;
extremely dangerous travel or impossible driving conditions,
extensive closures) for elevations generally above 5,000ft,
although some Major impacts as low as 4,000ft are possible. Major
to locally Extreme impacts are showing up in the peaks of the San
Gabriel and San Bernadino mountains, with mostly Moderate-to-Major
Impacts (increasingly more disruptive to travel jumping from
Moderate to Major). There are also likely to be some Major impacts
in the Coastal Range of northwest CA above 2,000ft. Note that there
are Minor to locally Moderate Impacts expected along I-5 around
Mount Shasta, signifying potential travel delays for I-5 in the
more elevated terrain of northern CA.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West this week that badly need the
boost in snowpack. With a lack of a frigid airmass ahead of this
healthy moisture source, the bulk of the heavy snow will be largely
confined to many of the taller mountain peaks. The heaviest
snowfall on Monday will reside in the Blue, Sawtooth, Wind River,
Uinta, and as far south as Mt. Charleston and the Mogollon Rim. WPC
72-hour probabilities are high (>70%) for snowfall totals >12" in
these mountain ranges through Thursday afternoon.

On Tuesday, the highly anomalous upper-low off the Pacific NW coast
will help to usher the initial upper low over southern CA east into
the Intermountain West, causing widespread height falls and a
larger plume of Pacific moisture to pass over the Rockies. The
potent closed low then heads inland over the interior NW and
northern Rockies on Wednesday while opening up into a trough,
prompting snow levels to crash and most valleys are likely to see at
least a coating of snow. Still, the lack of a frigid airmass at the
surface will keep the bulk of the heavy snow in the mountains with
ranges such as the Wasatch, Bear River, Tetons, Uinta, Wind River,
Mogollon Rim, and CO Rockies seeing anywhere from 1-2 feet of snow.
Expect Minor to Moderate Impacts, per the WSSI, with travel over
passes from the Lewis Range and Bitterroots to as far south as the
Mogollon Rim likely to contend with hazardous travel conditions.

By Thursday, much of the Intermountain West will be in a lull
between storm systems, as the next in the series of shortwaves
moves across California. Some snow will spill over into much of
Nevada, while areas further east see the snow stop completely
during the day. Snow with the shortwave over California moves
across the Four Corners into Thursday night and Friday.


...Northern Plains & Upper Great Lakes...
Days 2-3...

A shortwave emerging form the Great Basin will track rapidly northeast
Tuesday, reaching the Dakotas Tuesday evening while amplifying. As this
trough becomes negatively tilted and expands across the Northern Plains/Upper Midwest, it will interact with the LFQ of a strengthening subtropical jet streak arcing from the Desert Southwest to the Great Lakes, to support
surface cyclogensis Tuesday evening. This low is then expected to move
very slowly through Wednesday before gradually filling over the Western
Great Lakes Thursday night.

As this low tracks slowly eastward, it will interact with impressive
IVT surging above the 99th climatological percentile into Minnesota,
with the accompanying moisture and theta-e ridge axis then wrapping cyclonically
around the system and lifting into a pronounced TROWAL. The
associated synoptic lift, aided by increasing WAA, will expand precipitation across the northern tier of the CONUS from far eastern MT through the
western Great Lakes, with periods of heavy snow likely as strongly sloped
FGEN driving omega into the TROWAL supports heavy preciptiation rates.
The most impressive ascent appears to intersect the DGZ, so despite this
being subjectively elevated (nearing 500mb) it will support heavy snow
rates and dynamic cooling into a column that is initially too warm to
support snow. However, once precipitation changes to snow, it will become heavy, supported by the WAA/fgen beneath the TROWAL and accompanying
CSI evident in cross- sections, to support rates that will likely exceed
1"/hr at times (60-90% chance). These intense rates will be accompanied
by strong and gusty winds, resulting in widespread moderate impacts (30-60% chance) from ND through the Arrowhead of MN. Here, there is a high probability (>70% chance) of more than 4 inches of snowfall accumulating, with locally
8-10 inches possible. Some even higher totals, exceeding 12 inches, may
occur (30-50% chance) along the Arrowhead of MN where upslope flow with
lake- enhanced moisture will combine to bring greater snowfall and resulting impacts.

Additionally, with the pronounced WAA rotating around the surface low,
an area of freezing rain is also expected, especially from near Duluth,
MN eastward across northern WI and into northern MI where the warm nose
will be most prevalant, but low-level easterly flow will maintain sub-
freezing surface temperatures. In this area, WPC probabilities are moderate (50-70%) for at least 0.1" of ice, with locally more than 0.25" possible,
most likely across the northern L.P. of MI.


...Northeast...
Days 2-3...

A strong surface low moving slowly across the Dakotas/Minnesota Wednesday
will remain entrenched within an elongated mid-level trough extending
into the Mid-Atlantic states. Vorticity lobes downstream of this wave
will spread northeast from the Mid-Atlantic states into the Northeast,
before getting sheared rapidly to the east as mid- level flow becomes
strongly confluent south of secondary shortwave energy crossing Maine
and Nova Scotia. The resultant mid- level PVA and divergence will overlap
with a narrow ribbon of impressive low- level WAA to produce a stripe
of heavy precipitation from Upstate NY through southern/central New England.

This precipitation will expand eastward from the Great Lakes Wednesday
morning, exiting off the New England coast by Thursday morning. While
the guidance continues to feature some latitudinal variability within
what will likely be a narrow corridor of precipitation, the evolution
of the upper jet streak (initially downstream a poleward arcing, but
becoming more zonal and stretch south of the precipitation) will force
a quasi-laterally translating band of precipitation, but with slow weakening
of intensity through Thursday morning. This is reflected by just modest
fgen in the 925- 850mb layer, and although some fgen may increase late
as a surface wave develops offshore leading to more pronounced low-
level convergence over New England, this will occur as the column dries
from the top down, limiting moist ascent, so most of the precipitation
should remain of modest intensity, with locally higher rates possible, especially Wednesday, during the period of most impressive WAA.

Thermally, the antecedent column is marginal to support wintry precipitation, and it appears any significant snowfall accumulations will be confined
to higher elevations above 1,000 ft, or where the most intense dynamic
cooling can overwhelm the above-freezing low- levels. This is most likely
from Upstate NY into western VT where conditional instability into a DGZ
of modest depth is possible (30% chance from the SREF). This will support briefly heavier snowfall rates, which could linger as the band of preciptation tracks along its long axis. This is reflected by WPC probabilities that
reach as high as 10-30% for 4+ inches of snow, especially in the Adirondacks and Greens, with moderate probabilities for 2+ inches covering much of
central New England and the northern half of Upstate NY. It is important
to note that the WSE mean snowfall for much of this area lies well below
the maximum values, so some locally higher amounts are probable where
any banding persists. South of this axis of moderate to heavy snow, a
corridor of icing exceeding 0.1" is possible (10-30% chance) from the
southern shore of Lake Ontario through the capital region of NY near Albany.


Weiss/Wegman


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 162023
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
323 PM EST Mon Feb 16 2026

Valid 00Z Tue Feb 17 2026 - 00Z Fri Feb 20 2026


...Pacific & Interior Northwest...
Days 1-3...

An active period of winter weather expected this week across the
Pacific and Interior Northwest as repeated shortwaves dive through a
longwave trough entrenched across the region.

The period begins with increasing southerly mid-level flow downstream
of the lead shortwave which will be digging along the British Columbia
coast. This shortwave will continue to expand southward, with the trough
axis finally moving onshore WA/OR Tuesday night. This impulse will continue
to track eastward into the Great Basin and Northern Rockies on Wednesday,
with a secondary shortwave moving onshore immediately in its wake. This mid-level evolution will push 500mb heights down below the 0.5 climatological percentile tonight through Wednesday morning, leading to snow levels
for which the NBM suggests will fall below 1000 ft as far as northern
CA, with the 10th percentile (which may be a better proxy due to steep
lapse rates beneath the cold core trough aloft) dropping to the surface
across most of the area. While the heaviest precipitation is expected
within surges of WAA D1 and D3, this could result in the first light
snowfall accumulations down to the valley floors and lowlands of WA
and OR.

For D1, the heaviest precipitation is expected across OR and into
ID, as well as the southern WA Cascades. Here, the IVT will maximize
within the broad WAA plume and within broad mid-level divergence/height
falls downstream of the lead shortwave trough. Additionally, S/SW flow
will impinge favorably into the Cascades for upslope enhancement, with
snow levels falling well below pass levels, including potentially even
to I-5 through the Willamette Valley. The heaviest snow is expected above
2,000 ft, where WPC probabilities are high (>70%) D1 and low (30%) D2
for 4+ inches each day, leading to locally more than 12 inches of snowfall through 00Z/Thursday. This will create hazardous travel, especially
across Santiam, Willamette, and Siskiyou Passes. Light snow accumulations
are expected even onto the Coastal terrain of WA/OR where there exists
a 30-50% chance of at least 2 inches.

A brief break in precipitation is expected much of D2 before the second shortwave approaches with renewed ascent and moisture spreading into
the area. A period of renewed snow is likely, especially across the
WA/OR Cascades and surrounding lowlands as snow levels again fall below
500 ft. WPC probabilities for at least 1 inch of snow reach 30% even
into the Portland, OR metro area and surrounding Seattle, WA, with
an additional 6+ inches of snowfall likely (70% chance) across the
southern WA and most of the OR Cascades.


...California...
Days 1-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges this week...

A series of potent Pacific storm systems are working together to
direct copious amounts of moisture at the mountain ranges of the
"Golden State". While heavy snow has been unfolding in the
Siskiyou, Shasta, Trinity, and Salmon mountains of northern CA
since Sunday, very heavy snowfall has been ongoing today along the
Sierra Nevada with snow levels currently between 5,000 and
6,000ft. Tonight, the snow levels will drop precipitously to then
falling to as low as 2,500ft by Tuesday morning in the northern
Sierra, and 4,000 ft for the southern Sierra Nevada. Snowfall rates
between 1-2"/hr will be common with some instances of >3"/hr
snowfall rates in the central and southern Sierra Nevada. Heavy
snow will continue through tonight in the Transverse Ranges above
6,000ft. This first disturbance is the result of a strong shortwave
trough that will be pivoting east into California through this
evening. By Tuesday morning that upper level energy will be well
into the Intermountain west, through upsloping and a surface trough
will keep higher elevation snow going through tonight, albeit with
decreasing intensity.

On Tuesday, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second, arguably stronger
upper level low dives south along the West Coast, closely following
the first. This will spike onshore flow and additional moisture
supply on the southern and eastern flanks of the upper low. Renewed
heavy snow will start out across the northern California ranges
Tuesday morning, then spread south down the Sierra Nevada from
Tuesday afternoon through Tuesday night. Once again, 1-2 inch/hour
rates will be common with 3-4 inch/hour rates locally not out of
the question. Snow levels will continue to fall to around 1,000 ft
in far northern California (including the northern coastal range)
Tuesday night, around 2,500ft in the Sierra Nevada, and between
4,000 and 5,000 ft into the Transverse Ranges. Snow will continue
to fall across California's mountain ranges trough Wednesday as yet
another 500mb shortwave trough west of WA continues to sustain
what feels like an endless supply of Pacific moisture into the
Golden State. However, during the day Wednesday snowfall rates
could diminish in most of the mountains down to light snow or even
flurries at times. With the longwave trough overhead, snow levels
could creep down as low as 1,000ft in central CA and may support
minor accumulations down to 1,000ft.

On Thursday a pair of shortwaves, both moving SSE, but one
impacting the Northern California ranges, and the other following
the previous disturbances hugging the coast until it turns inland
over Southern California, will keep moderate snow ongoing along
most of California's ranges. Rates will not be quite as heavy on
Thursday as on previous days. Snow levels will fall in the
Transverse Ranges to as low as 3,500 feet Thursday morning, while
staying between 1,500 and 2,500 feet from the Sierra Nevada north.

California's mountain ranges welcome the snow, although it will
come down fast and furious through mid-week. Through the end of
this discussion's timeframe (00Z Fri), snowfall will be measured
in feet above 4,000ft along the Sierra Nevada. WPC probabilities
show high chances (>90%) for >30" of snow along Donner Pass through
00Z Friday and more snow still to come. The WSSI shows a large
swath of Extreme Impacts (Substantial disruptions to daily life;
extremely dangerous travel or impossible driving conditions,
extensive closures) for elevations generally above 5,000ft,
although some Major impacts as low as 4,000ft are possible. Major
to locally Extreme impacts are showing up in the peaks of the San
Gabriel and San Bernadino mountains, with mostly Moderate-to-Major
Impacts (increasingly more disruptive to travel jumping from
Moderate to Major). There are also likely to be some Major impacts
in the Coastal Range of northwest CA above 2,000ft. Note that there
are Minor to locally Moderate Impacts expected along I-5 around
Mount Shasta, signifying potential travel delays for I-5 in the
more elevated terrain of northern CA.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West this week that badly need the
boost in snowpack. With a lack of a frigid airmass ahead of this
healthy moisture source, the bulk of the heavy snow will be largely
confined to many of the taller mountain peaks. The heaviest
snowfall on Monday will reside in the Blue, Sawtooth, Wind River,
Uinta, and as far south as Mt. Charleston and the Mogollon Rim. WPC
72-hour probabilities are high (>70%) for snowfall totals >12" in
these mountain ranges through Thursday afternoon.

On Tuesday, the highly anomalous upper-low off the Pacific NW coast
will help to usher the initial upper low over southern CA east into
the Intermountain West, causing widespread height falls and a
larger plume of Pacific moisture to pass over the Rockies. The
potent closed low then heads inland over the interior NW and
northern Rockies on Wednesday while opening up into a trough,
prompting snow levels to crash and most valleys are likely to see at
least a coating of snow. Still, the lack of a frigid airmass at the
surface will keep the bulk of the heavy snow in the mountains with
ranges such as the Wasatch, Bear River, Tetons, Uinta, Wind River,
Mogollon Rim, and CO Rockies seeing anywhere from 1-2 feet of snow.
Expect Minor to Moderate Impacts, per the WSSI, with travel over
passes from the Lewis Range and Bitterroots to as far south as the
Mogollon Rim likely to contend with hazardous travel conditions.

By Thursday, much of the Intermountain West will be in a lull
between storm systems, as the next in the series of shortwaves
moves across California. Some snow will spill over into much of
Nevada, while areas further east see the snow stop completely
during the day. Snow with the shortwave over California moves
across the Four Corners into Thursday night and Friday.


...Northern Plains & Upper Great Lakes...
Days 2-3...

A shortwave emerging form the Great Basin will track rapidly
northeast Tuesday, reaching the Dakotas Tuesday evening while amplifying.
As this trough becomes negatively tilted and expands across the Northern Plains/Upper Midwest, it will interact with the LFQ of a strengthening subtropical jet streak arcing from the Desert Southwest to the Great
Lakes, to support surface cyclogenesis Tuesday evening. This low
is then expected to move very slowly through Wednesday before
gradually filling over the Western Great Lakes Thursday night.

As this low tracks slowly eastward, it will interact with impressive
IVT surging above the 99th climatological percentile into Minnesota,
with the accompanying moisture and theta-e ridge axis then wrapping cyclonically around the system and lifting into a pronounced TROWAL.
The associated synoptic lift, aided by increasing WAA, will expand precipitation
across the northern tier of the CONUS from far eastern MT through the
western Great Lakes, with periods of heavy snow likely as strongly sloped
FGEN driving omega into the TROWAL supports heavy precipitation
rates. The most impressive ascent appears to intersect the DGZ, so
despite this being subjectively elevated (nearing 500mb) it will
support heavy snow rates and dynamic cooling into a column that is
initially too warm to support snow. However, once precipitation
changes to snow, it will become heavy, supported by the WAA/fgen
beneath the TROWAL and accompanying CSI evident in cross- sections,
to support rates that will likely exceed 1"/hr at times (60-90%
chance). These intense rates will be accompanied by strong and
gusty winds, resulting in widespread moderate impacts (30-60%
chance) from ND through the Arrowhead of MN. Here, there is a high
probability (>70% chance) of more than 4 inches of snowfall
accumulating, with locally 8-10 inches possible. Some even higher
totals, exceeding 12 inches, may occur (30-50% chance) along the
Arrowhead of MN where upslope flow with lake- enhanced moisture
will combine to bring greater snowfall and resulting impacts.

Additionally, with the pronounced WAA rotating around the surface low,
an area of freezing rain is also expected, especially from near Duluth,
MN eastward across northern WI and into northern MI where the warm nose
will be most prevalent, but low-level easterly flow will maintain
sub- freezing surface temperatures. In this area, WPC probabilities
are moderate (50-70%) for at least 0.1" of ice, with locally more
than 0.25" possible, most likely across the northern L.P. of MI.


...Northeast...
Days 2-3...

A strong surface low moving slowly across the Dakotas/Minnesota
Wednesday will remain entrenched within an elongated mid-level
trough extending into the Mid-Atlantic states. Vorticity lobes
downstream of this wave will spread northeast from the Mid-Atlantic
states into the Northeast, before getting sheared rapidly to the east
as mid- level flow becomes strongly confluent south of secondary shortwave energy crossing Maine and Nova Scotia. The resultant mid-level PVA
and divergence will overlap with a narrow ribbon of impressive low-
level WAA to produce a stripe of heavy precipitation from Upstate NY
through southern/central New England.

This precipitation will expand eastward from the Great Lakes Wednesday
morning, exiting off the New England coast by Thursday morning. While
the guidance continues to feature some latitudinal variability within
what will likely be a narrow corridor of precipitation, the evolution
of the upper jet streak (initially downstream a poleward arcing, but
becoming more zonal and stretch south of the precipitation) will force
a quasi-laterally translating band of precipitation, but with slow weakening
of intensity through Thursday morning. This is reflected by just modest
fgen in the 925- 850mb layer, and although some fgen may increase late
as a surface wave develops offshore leading to more pronounced low-
level convergence over New England, this will occur as the column dries
from the top down, limiting moist ascent, so most of the precipitation
should remain of modest intensity, with locally higher rates possible, especially Wednesday, during the period of most impressive WAA.

Thermally, the antecedent column is marginal to support wintry precipitation, and it appears any significant snowfall accumulations will be confined
to higher elevations above 1,000 ft, or where the most intense dynamic
cooling can overwhelm the above- freezing low- levels. This is most
likely from Upstate NY into western VT where conditional instability
into a DGZ of modest depth is possible (30% chance from the SREF). This
will support briefly heavier snowfall rates, which could linger as the
band of precipitation tracks along its long axis. This is
reflected by WPC probabilities that reach as high as 10-30% for 4+
inches of snow, especially in the Adirondacks and Greens, with
moderate probabilities for 2+ inches covering much of central New
England and the northern half of Upstate NY. It is important to
note that the WSE mean snowfall for much of this area lies well
below the maximum values, so some locally higher amounts are
probable where any banding persists. South of this axis of moderate
to heavy snow, a corridor of icing exceeding 0.1" is possible
(10-30% chance) from the southern shore of Lake Ontario through the
capital region of NY near Albany.


Weiss/Wegman


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 162220
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
520 PM EST Mon Feb 16 2026

Valid 00Z Tue Feb 17 2026 - 00Z Fri Feb 20 2026


...Pacific & Interior Northwest...
Days 1-3...

An active period of winter weather expected this week across the
Pacific and Interior Northwest as repeated shortwaves dive through
a longwave trough entrenched across the region.

The period begins with increasing southerly mid-level flow
downstream of the lead shortwave which will be digging south down
the British Columbia coast. This shortwave will continue to expand
southward, with the trough axis finally moving onshore WA/OR
Tuesday night. This impulse will continue to track eastward into
the Great Basin and Northern Rockies on Wednesday, with a secondary
shortwave moving onshore immediately in its wake. This mid-level
evolution will push 500mb heights down below the 0.5 climatological
percentile tonight through Wednesday morning, leading to snow
levels for which the NBM suggests will fall below 1,000 feet as far
south as northern CA. The 10th percentile (which may be a better
proxy due to steep lapse rates beneath the cold core trough aloft)
dropping to the surface across most of the area. While the heaviest precipitation is expected within surges of WAA D1 and D3, this
could result in the first light snowfall accumulations down to the
valley floors and lowlands of WA and OR.

For D1, the heaviest precipitation is expected across OR and into
ID, as well as the southern WA Cascades. Here, the IVT will
maximize within the broad WAA plume and within broad mid-level divergence/height falls downstream of the lead shortwave trough.
Additionally, S/SW flow will impinge favorably into the Cascades
for upslope enhancement, with snow levels falling well below pass
levels. This includes potentially down to I-5 through the
Willamette Valley. The heaviest snow is expected above 2,000 ft,
where WPC probabilities are high (>70%) D1 and low (30%) D2 for 4+
inches each day, leading to locally more than 12 inches of snowfall
through 00Z/Thursday. This will create hazardous travel, especially
across Santiam, Willamette, and Siskiyou Passes. Light snow
accumulations are expected even onto the coastal terrain of WA/OR
where there exists a 30-50% chance of at least 2 inches.

A brief break in precipitation is expected much of D2 before the
second shortwave approaches with renewed ascent and moisture
spreading into the area. A period of renewed snow is likely,
especially across the WA/OR Cascades and surrounding lowlands as
snow levels again fall below 500 ft. WPC probabilities for at least
1 inch of snow reach 30% even into the Portland, OR metro area and
surrounding Seattle, WA, with an additional 6+ inches of snowfall
likely (70% chance) across the southern WA and most of the OR
Cascades.


...California...
Days 1-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges this week...

A series of potent Pacific storm systems are working together to
direct copious amounts of moisture at the mountain ranges of the
"Golden State". While heavy snow has been unfolding in the
Siskiyou, Shasta, Trinity, and Salmon mountains of northern CA
since Sunday, very heavy snowfall has been ongoing today along the
Sierra Nevada with snow levels currently between 5,000 and
6,000ft. Tonight, the snow levels will drop precipitously to then
falling to as low as 2,500ft by Tuesday morning in the northern
Sierra, and 4,000 ft for the southern Sierra Nevada. Snowfall rates
between 1-2"/hr will be common with some instances of >3"/hr
snowfall rates in the central and southern Sierra Nevada. Heavy
snow will continue through tonight in the Transverse Ranges above
6,000ft. This first disturbance is the result of a strong shortwave
trough that will be pivoting east into California through this
evening. By Tuesday morning that upper level energy will be well
into the Intermountain west, through upsloping and a surface trough
will keep higher elevation snow going through tonight, albeit with
decreasing intensity.

On Tuesday, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second, arguably stronger
upper level low dives south along the West Coast, closely following
the first. This will spike onshore flow and additional moisture
supply on the southern and eastern flanks of the upper low. Renewed
heavy snow will start out across the northern California ranges
Tuesday morning, then spread south down the Sierra Nevada from
Tuesday afternoon through Tuesday night. Once again, 1-2 inch/hour
rates will be common with 3-4 inch/hour rates locally not out of
the question. Snow levels will continue to fall to around 1,000 ft
in far northern California (including the northern coastal range)
Tuesday night, around 2,500ft in the Sierra Nevada, and between
4,000 and 5,000 ft into the Transverse Ranges. Snow will continue
to fall across California's mountain ranges trough Wednesday as yet
another 500mb shortwave trough west of WA continues to sustain
what feels like an endless supply of Pacific moisture into the
Golden State. However, during the day Wednesday snowfall rates
could diminish in most of the mountains down to light snow or even
flurries at times. With the longwave trough overhead, snow levels
could creep down as low as 1,000ft in central CA and may support
minor accumulations down to 1,000ft.

On Thursday a pair of shortwaves, both moving SSE, but one
impacting the Northern California ranges, and the other following
the previous disturbances hugging the coast until it turns inland
over Southern California, will keep moderate snow ongoing along
most of California's ranges. Rates will not be quite as heavy on
Thursday as on previous days. Snow levels will fall in the
Transverse Ranges to as low as 3,500 feet Thursday morning, while
staying between 1,500 and 2,500 feet from the Sierra Nevada north.

California's mountain ranges welcome the snow, although it will
come down fast and furious through mid-week. Through the end of
this discussion's timeframe (00Z Fri), snowfall will be measured
in feet above 4,000ft along the Sierra Nevada. WPC probabilities
show high chances (>90%) for >30" of snow along Donner Pass through
00Z Friday and more snow still to come. The WSSI shows a large
swath of Extreme Impacts (Substantial disruptions to daily life;
extremely dangerous travel or impossible driving conditions,
extensive closures) for elevations generally above 5,000ft,
although some Major impacts as low as 4,000ft are possible. Major
to locally Extreme impacts are showing up in the peaks of the San
Gabriel and San Bernadino mountains, with mostly Moderate-to-Major
Impacts (increasingly more disruptive to travel jumping from
Moderate to Major). There are also likely to be some Major impacts
in the Coastal Range of northwest CA above 2,000ft. Note that there
are Minor to locally Moderate Impacts expected along I-5 around
Mount Shasta, signifying potential travel delays for I-5 in the
more elevated terrain of northern CA.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West this week that badly need the
boost in snowpack. With a lack of a frigid airmass ahead of this
healthy moisture source, the bulk of the heavy snow will be largely
confined to many of the taller mountain peaks. The heaviest
snowfall on Monday will reside in the Blue, Sawtooth, Wind River,
Uinta, and as far south as Mt. Charleston and the Mogollon Rim. WPC
72-hour probabilities are high (>70%) for snowfall totals >12" in
these mountain ranges through Thursday afternoon.

On Tuesday, the highly anomalous upper-low off the Pacific NW coast
will help to usher the initial upper low over southern CA east into
the Intermountain West, causing widespread height falls and a
larger plume of Pacific moisture to pass over the Rockies. The
potent closed low then heads inland over the interior NW and
northern Rockies on Wednesday while opening up into a trough,
prompting snow levels to crash and most valleys are likely to see at
least a coating of snow. Still, the lack of a frigid airmass at the
surface will keep the bulk of the heavy snow in the mountains with
ranges such as the Wasatch, Bear River, Tetons, Uinta, Wind River,
Mogollon Rim, and CO Rockies seeing anywhere from 1-2 feet of snow.
Expect Minor to Moderate Impacts, per the WSSI, with travel over
passes from the Lewis Range and Bitterroots to as far south as the
Mogollon Rim likely to contend with hazardous travel conditions.

By Thursday, much of the Intermountain West will be in a lull
between storm systems, as the next in the series of shortwaves
moves across California. Some snow will spill over into much of
Nevada, while areas further east see the snow stop completely
during the day. Snow with the shortwave over California moves
across the Four Corners into Thursday night and Friday.


...Northern Plains & Upper Great Lakes...
Days 2-3...

A shortwave emerging from the Great Basin will track rapidly
northeast Tuesday, reaching the Dakotas Tuesday evening while
amplifying. As this trough becomes negatively tilted and expands
across the Northern Plains/Upper Midwest, it will interact with the
LFQ of a strengthening subtropical jet streak arcing from the
Desert Southwest to the Great Lakes. This setup will support
surface cyclogenesis Tuesday evening. This low is then expected to
move very slowly through Wednesday before gradually filling over
the western Great Lakes Thursday night.

As this low tracks slowly eastward, it will interact with
impressive IVT surging above the 99th climatological percentile
into Minnesota. The accompanying moisture and theta-e ridge axis
will then wrap cyclonically around the system and lift into a
pronounced TROWAL. The associated synoptic lift, aided by
increasing WAA, will expand precipitation across the northern tier
of the CONUS from far eastern MT through the western Great Lakes.
Periods of heavy snow are likely as strongly sloped FGEN driving
omega into the TROWAL supports heavy precipitation rates. The most
impressive ascent appears to intersect the DGZ, so despite this
being subjectively elevated (nearing 500 mb), it will support heavy
snow rates and dynamic cooling into a column that is initially too
warm to support snow. However, once precipitation changes to snow,
it will become heavy, supported by the WAA/FGEN beneath the TROWAL
and accompanying CSI evident in cross-sections, supporting rates
that will likely exceed 1"/hr at times (60-90% chance). These
intense rates will be accompanied by strong and gusty winds,
resulting in widespread moderate impacts (30-60% chance) from ND
through the Arrowhead of MN. Here, there is a high probability

70% chance) of more than 4 inches of snowfall accumulating, with

locally 8-10 inches possible. Some even higher totals, exceeding 12
inches, may occur (30-50% chance) along the Arrowhead of MN, where
upslope flow with lake-enhanced moisture will combine to bring
greater snowfall and subsequent impacts.

Additionally, with the pronounced WAA rotating around the surface
low, an area of freezing rain is also expected, especially from
near Duluth, MN eastward across northern WI and into northern MI
where the warm nose will be most prevalent. Low-level easterly flow
will maintain sub-freezing surface temperatures in these same
areas, setting the stage for a freezing rain/icing event. WPC
probabilities are moderate (50-70%) for at least 1/10 inch of ice,
with locally more than a quarter inch possible, most likely across
the northern L.P. of MI.


...Northeast...
Days 2-3...

A strong surface low moving slowly across the Dakotas/Minnesota
Wednesday will remain entrenched within an elongated mid-level
trough extending into the Mid-Atlantic states. Vorticity lobes
downstream of this wave will spread northeast from the Mid-Atlantic
states into the Northeast, before getting sheared rapidly to the
east as mid-level flow becomes strongly confluent south of the
secondary shortwave energy crossing Maine and Nova Scotia. The
resultant mid-level PVA and divergence will overlap with a narrow
ribbon of impressive low-level WAA to produce a stripe of heavy
precipitation from Upstate NY through southern/central New
England.

This precipitation will expand eastward from the Great Lakes
Wednesday morning, exiting off the New England coast by Thursday
morning. The guidance continues to feature some latitudinal
variability within what will likely be a narrow corridor of
precipitation. The evolution of the upper jet stream (initially
downstream a poleward arcing, but becoming more zonal and
stretching south of the precipitation) will force a quasi-
laterally translating band of precipitation, but with slow
weakening of intensity through Thursday morning. This is reflected
by just modest fgen in the 925-850 mb layer, and although some fgen
may increase late as a surface wave develops offshore leading to
more pronounced low-level convergence over New England, this will
occur as the column dries from the top down. This will limit moist
ascent, so most of the precipitation should remain of modest
intensity, with locally higher rates possible. This is most likely
on Wednesday, during the period of most impressive WAA.

Thermally, the antecedent column is marginal to support wintry
precipitation, and it appears any significant snowfall accumulation
will be contained both to higher elevations above 1,000 ft, and to
where the most intense dynamic cooling can overwhelm the above-
freezing low levels. The most significant accumulations are most
likely from upstate NY into western VT where conditional
instability into a DGZ of modest depth is possible (30% chance from
the SREF). This will support briefly heavier snowfall rates, which
could linger as the band of precipitation tracks along its long
axis. This is reflected by WPC probabilities that reach as high as
10-30% for 4+ inches of snow, especially in the Adirondacks and
Greens, with moderate probabilities for 2+ inches covering much of
central New England and the northern half of upstate NY. It is
important to note that the WSE mean snowfall for much of this area
lies well below the maximum values, so some locally higher amounts
are probable where any banding persists. South of this axis of
moderate to heavy snow, a corridor of icing exceeding 0.1" is
possible (10-30% chance) from the southern shore of Lake Ontario
through the Capital Region of NY.


Weiss/Wegman





$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 170743
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
243 AM EST Tue Feb 17 2026

Valid 12Z Tue Feb 17 2026 - 12Z Fri Feb 20 2026


...Pacific & Interior Northwest...
Days 1-3...

An active period of winter weather expected this week across the
Pacific and Interior Northwest as repeated shortwaves dive through
a longwave trough entrenched across the region.

Increasing southerly mid-level flow downstream of the lead
shortwave which will dive south along the British Columbia coast.
This shortwave will continue to expand southward, with the trough
axis finally moving onshore WA/OR Tuesday night. This impulse will
continue to track eastward into the Great Basin and Northern
Rockies on Wednesday, with a secondary shortwave moving onshore
immediately in its wake. This mid-level evolution will push 500mb
heights down below the 0.5 climatological percentile today and through Wednesday morning, leading to snow levels for which the NBM
suggests will fall below 1,000 feet as far south as northern CA.
The 10th percentile (a better proxy due to steep lapse rates
beneath the cold core trough aloft) dropping to the surface across
most of the area. While the heaviest precipitation is expected
within surges of WAA through mid-week, this is likely to produce
the first light snowfall accumulations down to the valley floors
and lowlands of WA and OR.

For Tuesday, the heaviest precipitation is expected across OR and
into ID, as well as the southern WA Cascades. Here, the IVT will
maximize within the broad WAA plume and within broad mid-level divergence/height falls downstream of the lead shortwave trough.
Additionally, S/SW flow will impinge favorably into the Cascades
for upslope enhancement, with snow levels falling well below pass
levels. This includes potentially down to I-5 through the
Willamette Valley. The heaviest snow is expected above 2,000 ft,
where WPC probabilities are high (>70%) for Tuesday and low (30%)
Wednesday for 4+ inches each day, leading to locally more than 12
inches of snowfall through 00Z/Thursday. This will create hazardous
travel, especially across Santiam, Willamette, and Siskiyou
Passes. Light snow accumulations are expected even onto the coastal
terrain of WA/OR where there exists a 30-50% chance of at least 2
inches.

A brief break in precipitation is expected Tuesday night before
the second shortwave approaches with renewed ascent aloft and
moisture spreading throughout the region. Moderate to locally is
likely, especially across the WA/OR Cascades and surrounding
lowlands as snow levels again fall below 500 ft. WPC probabilities
for at least 1 inch of snow reach 30% even into the Portland, OR
metro area and surrounding Seattle, WA, with an additional 6+
inches of snowfall likely (70% chance) across the southern WA and
most of the OR Cascades.


...California...
Days 1-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges this week...

A series of potent Pacific storm systems are working together to
direct copious amounts of moisture at the mountain ranges of the
"Golden State". After snow levels steadily fell throughout the
night, today, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second and more amplified
upper level low dives south along the West Coast. This will spike
onshore flow and additional moisture supply on the southern and
eastern flanks of the upper low. Renewed heavy snow will start out
across the northern California ranges Tuesday morning, then spread
south down the Sierra Nevada from Tuesday afternoon through Tuesday
night. Once again, 1-2 inch/hour rates will be common with 3-4
inch/hour rates possible locally. Snow levels will continue to
fall to around 1,000 ft in far northern California (including the
northern coastal range) Tuesday night, around 2,500ft in the Sierra
Nevada, and between 4,000ft and 5,000ft into the Transverse
Ranges. Snow will continue to fall across California's mountain
ranges trough Wednesday as yet another 500mb shortwave trough west
of WA continues to sustain what feels like an endless supply of
Pacific moisture into the Golden State. However, during the day
Wednesday snowfall rates could diminish in most of the mountains
down to light snow or even flurries at times. With the longwave
trough overhead, snow levels could creep down as low as 1,000ft in
central CA and may support minor accumulations down to 1,000ft.

On Thursday a pair of shortwaves, both moving SSE, but one
impacting the Northern California ranges, and the other following
the previous disturbances hugging the coast until it turns inland
over Southern California, will keep moderate snow ongoing along
most of California's ranges. Rates will not be quite as heavy on
Thursday as on previous days. Snow levels will fall in the
Transverse Ranges to as low as 3,500 feet Thursday morning, while
staying between 1,500 and 2,500 feet from the Sierra Nevada north.

California's mountain ranges welcome the snow, although it will
come down fast and furious through mid-week. Through the end of
this discussion's timeframe (12Z Fri), snowfall will be measured
in feet above 4,000ft along the Sierra Nevada. Several additional
feet of snow is forecast along Donner Pass through 12Z Friday and
more snow still to come. The WSSI shows a large swath of Extreme
Impacts (Substantial disruptions to daily life; extremely dangerous
travel or impossible driving conditions, extensive closures) for
elevations generally above 5,000ft, although some Major impacts as
low as 4,000ft are possible. Major to locally Extreme impacts are
showing up in the peaks of the San Gabriel and San Bernadino
mountains, with mostly Moderate-to-Major Impacts (increasingly more
disruptive to travel jumping from Moderate to Major). There are
also likely to be some Major impacts in the Coastal Range of
northwest CA above 2,000ft. Note that there are Minor to locally
Moderate Impacts expected along I-5 around Mount Shasta, signifying
potential travel delays for I-5 in the more elevated terrain of
northern CA.


...Intermountain West...
Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West this week that badly need the
boost in snowpack. With a lack of a frigid airmass ahead of this
healthy moisture source, the bulk of the heavy snow will be largely
confined to many of the taller mountain peaks. The heaviest
snowfall on Monday will reside in the Blue, Sawtooth, Wind River,
Uinta, and as far south as Mt. Charleston and the Mogollon Rim. WPC
72-hour probabilities are high (>70%) for snowfall totals >12" in
these mountain ranges through Thursday afternoon.

On Tuesday, the highly anomalous upper-low off the Pacific NW coast
will help to usher the initial upper low over southern CA east into
the Intermountain West, causing widespread height falls and a
larger plume of Pacific moisture to pass over the Rockies. The
potent closed low then heads inland over the interior NW and
northern Rockies on Wednesday while opening up into a trough,
prompting snow levels to crash and most valleys are likely to see at
least a coating of snow. By Thursday, much of the Intermountain
West will be in a lull between storm systems, as the next in the
series of shortwaves moves across California. Some snow will spill
over into much of Nevada, while areas further east see the snow
stop completely during the day. Snow with the shortwave over
California moves across the Four Corners into Thursday night and
Friday.

The bulk of the heavy snow will be observed in mountain ranges such
as the Wasatch, Bear River, Tetons, Uinta, Wind River, Mogollon
Rim, and CO Rockies who are forecast to receive between 1-2 feet
of snow (locally up to 3 feet possible). Expect Minor to Moderate
Impacts, per the WSSI, with travel over passes from the Lewis Range
and Bitterroots to as far south as the Mogollon Rim likely to
contend with hazardous travel conditions. Some Major Impacts are
showing up in the more remote peaks of these mountain regions.


...Northern Plains & Upper Great Lakes...
Days 1-2...

A shortwave emerging from the Great Basin will track quickly to the northeast today, reaching the Dakotas later this evening while also
strengthening in the process. As this trough becomes negatively
tilted and expands across the Northern Plains/Upper Midwest, it
will interact with the LFQ of a strengthening subtropical jet
streak arcing from the Desert Southwest to the Great Lakes. This
setup will support surface cyclogenesis Tuesday evening. This low
is then expected to move very slowly through Wednesday before
gradually filling over the western Great Lakes Thursday night.

As this low tracks slowly eastward, it will interact with
impressive IVT surging above the 99th climatological percentile
into Minnesota. The accompanying moisture and theta-e ridge axis
will then wrap cyclonically around the system and lift into a
pronounced TROWAL. The associated synoptic lift, aided by
increasing WAA, will expand precipitation across the northern tier
of the CONUS from far eastern MT through the western Great Lakes.
Periods of heavy snow are likely as strongly sloped FGEN driving
omega into the TROWAL supports heavy precipitation rates. The most
impressive ascent appears to intersect the DGZ, so despite this
being subjectively elevated (nearing 500 mb), it will support heavy
snow rates and dynamic cooling into a column that is initially too
warm to support snow. However, once precipitation changes to snow,
it will become heavy, supported by the WAA/FGEN beneath the TROWAL
and accompanying CSI evident in cross-sections, supporting rates
that will likely exceed 1"/hr at times (>70% chance). These
intense rates will be accompanied by strong and gusty winds,
resulting in widespread moderate impacts (30-60% chance) from ND
through the Arrowhead of MN. It is in this swath of the Upper
Midwest where there are moderate-to-high chances (50-70%) for
snowfall totals >6", including as far east as the northern shores
of MI's Upper Peninsula. Some localized areas of northern ND and
northern MN could see totals approach 12", but it is the MN
Arrowhead that will see as much as 1-2 feet of snow with localized
totals topping 24". The WSSI-P shows moderate chances (40-60%) for
locally Major Impacts (considerable disruptions; dangerous driving
conditions and widespread closures).

Additionally, with the pronounced WAA rotating around the surface
low, an area of freezing rain is also expected, especially from
near Duluth, MN eastward across northern WI and into northern MI
where the warm nose will be most prevalent while surface temps
remain sub-freezing. This sets the stage for a freezing rain/icing
event that could last for over 24 hours in parts of northern WI and
northern MI. WPC probabilities are moderate (40-70%) for at least
1/10 inch of ice, with locally more than a quarter inch possible,
most likely across the tip of Michigan's Mitten.


...Northeast...
Day 2...

A strong surface low moving slowly across the Dakotas/Minnesota
Wednesday will remain entrenched within an elongated mid-level
trough extending into the Mid-Atlantic states. Vorticity lobes
downstream of this wave will spread northeast from the Mid-Atlantic
states into the Northeast, before getting sheared to the east as
mid-level flow becomes strongly confluent south of the secondary
shortwave energy crossing Maine and Nova Scotia. The resultant mid-
level PVA and divergence will overlap with a narrow ribbon of
impressive low-level WAA to produce a stripe of heavy precipitation
from Upstate NY through southern/central New England.

This precipitation will expand eastward from the Great Lakes
Wednesday morning, then exiting off the New England coast by
Thursday morning. Guidance is now coming into better agreement on
the placement over 925-850mb layer-averaged FGEN zone over the
southern tier of NY, that is favoring a swath of snow just north
of the FGEN band. Thermally, the antecedent column is marginal to
support wintry precipitation, and it appears any significant
snowfall accumulation will be contained both to higher elevations
above 1,000 ft, and to where the most intense dynamic cooling can
overwhelm the above- freezing low levels. The most significant
accumulations are most likely from upstate NY into western VT where
conditional instability into a DGZ is just supportive enough to
generate locally heavy rates.

This is reflected by WPC probabilities that reach as high as
10-40% for 4+ inches of snow, especially in the Adirondacks and
Greens, with moderate probabilities (40-70%) for >2 inches
covering much of central New England and the northern half of
upstate NY. It is important to note that the WSE mean snowfall for
much of this area remains below the maximum values, so some
locally higher amounts are probable where any banding persists.
South of this axis of moderate to heavy snow, a corridor of icing
exceeding 0.1" is possible (30-50% chance) from the southern shore
of Lake Ontario with low chances (10-30%) for over one-quarter
inch.


...Central Plains...
Day 3...

Wednesday night, a potent shortwave trough ejecting out of the
Central Rockies will take on a negative tilt as it heads into the
Central Plains. To the north of the 500mb vort max, strong 700mb
Q-vector confluence will focus a narrow area of strong vertical
velocities, coinciding with a pronounced TROWAL forming over the
Sand Hills of NE and southern SD early Thursday morning. While
there is lingering spread in guidance regarding the placement of
this band as it forms as far west as eastern WY and tracks as far
east as the MO River Valley Thursday evening, most guidance agrees
the impressive synoptic-scale support aloft (left-exit region of a
250mb jet streak over head) and strong SErly 850mb WAA will
support heavy snowfall rates. Latest WPC probabilities show
moderate chances (40-60%) for >4" of snow from eastern WY on east
along the NE/SD border and into southeast SD. It is worth noting
there are low chance probabilities (10-30%) for >8" of snowfall in
northern NE and southern SD. Given the strong dynamics and banding
potential, these are the kind of setups where seeing snowfall
totals are low chance over 48 hours out, but are very much within
reason. Residents in the Central Plains should monitor the forecast
from their local WFO closely in the coming days.


Mullinax/Weiss/Wegman





$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 171947
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
247 PM EST Tue Feb 17 2026

Valid 00Z Wed Feb 18 2026 - 00Z Sat Feb 21 2026


...Pacific & Interior Northwest...
Days 1-3...

An active pattern will continue through midweek as a series of
shortwaves rotate through a broad upper trough. The closed low
currently centered off of the Washington-Oregon coast will translate
into an open wave, with the trough axis forecast to move inland
overnight. While additional accumulations will be relatively light,
this transition will provide the necessary forcing and cold air to
support additional snow and drive snow levels lower through
Wednesday morning.

A brief period of shortwave ridging will support a lull in
precipitation on Wednesday. During this time, expect a slight
rebound in snow levels before the next impulse arrives.

By Thursday, an upstream shortwave diving south from the British
Columbia coast will move inland. While this feature will support an
uptick in regional precipitation, the more robust forcing and deeper
moisture are expected to focus from southeastern Oregon southward.
Low snow levels at the onset will be driven even lower by this
system, maintaining the threat of lowland snow accumulations.

Probabilities for additional accumulations exceeding 8 inches are
highest over the southern Oregon Cascades and the southern Oregon
coastal ranges above 2,000 ft. Probabilities for accumulations over
an inch climb to over 30 percent for the Portland area Wednesday
into early Thursday.

Precipitation is expected to diminish by late Thursday as the trough
axis departs to the east. Upper-level ridging will build in its
wake, likely persisting through late Friday - diminishing the
potential for widespread heavy snowfall.

...California...
Days 1-3...

...Multiple days of heavy, disruptive snowfall for the California
ranges...

Successive Pacific storms will funnel deep moisture into California
through midweek. Heavy snow continues this evening as amplified
energy digs into the base of an upper trough moving onshore. Heavy
snow will persist through the overnight into Wednesday along the
Sierra Nevada and southern California ranges.

Snow levels will plummet to 1,000 ft in far northern California,
2,500 ft in the Sierra Nevada, and 4,000-5,000 ft in the Transverse
Ranges tonight. Rates are expected to diminish on Wednesday as the
leading wave moves east; however, snow levels will remain low,
supporting snow accumulations down to 1,000 ft in central California.

On Thursday, phasing shortwaves diving southeast into the state will
support additional moderate snow across most ranges, although
intensity will be less than previous days.

Storm total accumulations exceeding two feet are likely for the
northern Sierra Nevada above 3,000-4,000 ft and in the southern
Sierra above 4,000-5,000 ft - with several feet possible at the
highest elevations. The WSSI-P continues to indicate widespread
Extreme impacts are likely for the central and southern Sierra
Nevada through into Wednesday before gradually diminishing. At
least Moderate Impacts along the Sierra Nevada I-80 corridor are
expected to persist into Friday.

In Southern California, WPC probabilities indicate storm total
accumulations over a foot are highest in the Transverse and northern
Peninsular ranges above 6,000 ft.

Similar to the Northwest, upper ridging will provide a break in the
heavy snowfall threat beginning late Thursday and continuing into
Friday.

...Intermountain West/Southwest to the Rockies...
Days 1-3...

Pacific moisture spilling over the Cascades and Sierra-Nevada will
provide a much-needed boost to the Intermountain and Rocky Mountain
snowpack.

Following a warm start, snow levels will drop into the valleys as
the leading shortwave moves inland on Wednesday. A brief lull is
expected on Thursday, except for Nevada and the Four Corners region,
where the next shortwave will bring the threat for heavy mountain
snow into Friday.

Probabilities for storm total amounts over a foot exceed 70 percent
for several areas including the high elevations of the Nevada
mountains, the southern Utah mountains, the northern Arizona plateaus
to the central Mogollon Rim, and much of the central Rockies -
particularly the northern Utah and western Colorado ranges.


...Northern Plains & Upper Great Lakes...
Days 1-2...

Current WV satellite imagery indicates a well-defined shortwave
trough navigating through the Rockies with a broad, diffluent axis
positioned downstream over the Northern Plains to Upper Midwest.
As this trough migrates northeast into the Northern Plains, the
expectation is for the trough to become negatively tilted and
expand eastward across the Northern Plains through the Upper
Midwest. At the surface, the development and subsequent maturation
of an area of low pressure will occur as the surface reflection
materializes and strengthens thanks to its positioning within the
LFQ of a strengthening subtropical jet streak arcing from the
Desert Southwest to the Great Lakes. This low is then expected to
move very slowly through Wednesday before gradually filling over
the western Great Lakes Thursday night, leading to an eventual end
of the storms impacts within the D1-2 time frame.

As this low tracks slowly eastward, it will interact with
impressive IVT surging above the 99th climatological percentile
into Minnesota according to NAEFS and global ensemble depictions, a
testament to a deep moisture feed that this storm will be able to
tap into when maturing over the Upper Midwest. The accompanying
moisture and theta-e ridge axis will then wrap cyclonically around
the system and lift into a pronounced TROWAL. The associated
synoptic lift, aided by increasing WAA, will expand precipitation
across the northern tier of the CONUS from far eastern MT through
the western Great Lakes. Periods of heavy snow are likely as
strongly sloped FGEN driving omega into the TROWAL supports heavy
precipitation rates. The most impressive ascent appears to
intersect the DGZ, so despite this being subjectively elevated
(nearing 500 mb), it will support heavy snow rates and dynamic
cooling into a column that is initially too warm to support snow.
However, once precipitation changes to snow, it will become heavy,
supported by the WAA/FGEN beneath the TROWAL and accompanying CSI
evident in cross-sections, supporting rates that will likely exceed
1"/hr at times (>70% chance). These intense rates will be
accompanied by strong and gusty winds, resulting in widespread
moderate impacts (40-80% chance) from ND through the Arrowhead of
MN. It is in this swath of the Upper Midwest where there are
moderate-to-high chances (50-90%) for snowfall totals >6",
including as far east as the northern shores of MI's Upper
Peninsula. The biggest change from the previous forecast was an
increase in the probabilities for >6" across the Arrowhead of
Minnesota where a broad area of >90% probability exists with >80%
for over 12".

Lower probabilities exist for some localized areas of northern ND
and northern MN that could see totals approach 12", but it is the
MN Arrowhead that will likely be the area of highest impact with
regards to snow totals for the event. At least 1-2 feet of snow
with totals topping 24" increasingly likely from Two Harbors to
Grand Portage and points inland along the MN-61 state highway that
parallel's the North Shore of Lake Superior. The WSSI-P continues
to show elevated chances (40-70%) for locally Major Impacts
(considerable disruptions; dangerous driving conditions and
widespread closures) driven heavily by the snow amounts forecast
across the area.

Additionally, with the pronounced WAA rotating around the surface
low, an area of freezing rain is also expected, especially from
near Duluth, MN eastward across northern WI and into northern MI
where the warm nose will be most prevalent while surface temps
remain sub-freezing. This sets the stage for a freezing rain/icing
event that could last for over 24 hours in parts of northern WI and
northern MI. WPC probabilities are moderate (40-80%) for at least
1/10 inch of ice, with locally more than a quarter inch possible,
most likely across the tip of Michigan's Mitten, mainly areas east
of Grand Traverse Bay.


...Northeast...
Day 2...

There has been very little change to the overall synoptic evolution
anticipated for the D2 time frame across the Northeastern U.S. A
strong surface low moving slowly across the Dakotas/Minnesota
Wednesday will remain entrenched within an elongated mid-level
trough extending into the Mid- Atlantic states. Vorticity lobes
downstream of this wave will spread northeast from the Mid-Atlantic
states into the Northeast, before getting sheared to the east as
mid-level flow becomes strongly confluent south of the secondary
shortwave energy crossing Maine and Nova Scotia. The resultant mid-
level PVA and divergence will overlap with a narrow ribbon of
impressive low- level WAA to produce a stripe of heavy
precipitation from Upstate NY through southern/central New England.

This precipitation will expand eastward from the Great Lakes
Wednesday morning, then exiting off the New England coast by
Thursday morning. Guidance is now coming into better agreement on
the placement over 925-850mb layer-averaged FGEN zone over the
southern tier of NY, that is favoring a swath of snow just north
of the FGEN band. Thermally, the antecedent column is marginal to
support wintry precipitation, and it appears any significant
snowfall accumulation will be contained both to higher elevations
above 1,000 ft, and to where the most intense dynamic cooling can
overwhelm the above- freezing low levels. The most significant
accumulations are most likely from upstate NY into western VT where
conditional instability into a DGZ is just supportive enough to
generate locally heavy rates.

This is reflected by WPC probabilities that reach as high as
10-40% for 4+ inches of snow, especially in the Adirondacks and
Greens, with moderate probabilities (40-70%) for >2 inches
covering much of central New England and the northern half of
upstate NY. It is important to note that the WSE mean snowfall for
much of this area remains below the maximum values, so some
locally higher amounts are probable where any banding persists.
South of this axis of moderate to heavy snow, a corridor of icing
exceeding 0.1" is possible (30-50% chance) from the southern shore
of Lake Ontario with low chances (10-30%) for over one-quarter
inch.


...Central Plains...
Day 2-3...

Wednesday night, a potent shortwave trough ejecting out of the
Central Rockies will take on a negative tilt as it heads into the
Central Plains. To the north of the 500mb vort max, strong 700mb
Q-vector confluence will focus a narrow area of strong vertical
velocities, coinciding with a pronounced TROWAL forming over the
Sand Hills of NE and southern SD early Thursday morning. While
there is lingering spread in guidance regarding the placement of
this band as it forms as far west as eastern WY and tracks as far
east as the MO River Valley Thursday evening, most guidance agrees
the impressive synoptic-scale support aloft (left-exit region of a
250mb jet streak over head) and strong SErly 850mb WAA will
support heavy snowfall rates. Latest WPC probabilities show
moderate chances (40-80%) for >4" of snow from eastern WY on east
along the NE/SD border and into southeast SD. It is worth noting
there are low chance probabilities (10-40%) for >8" of snowfall in
northwestern NE and along the southwest SD border. Given the
strong dynamics and banding potential, these are the kind of setups
where seeing snowfall totals are low chance over 48 hours out, but
are very much within reason. Residents in the Central Plains
should monitor the forecast from their local WFO closely in the
coming days.


Mullinax/Kleebauer/Pereira



$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 180725
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
225 AM EST Wed Feb 18 2026

Valid 12Z Wed Feb 18 2026 - 12Z Sat Feb 21 2026


...Pacific & Interior Northwest...
Days 1-2...

The longwave trough that has led to multiple days worth of
accumulating snowfall looks to continue through at least Thursday
morning before a upper level ridge pattern builds in late in the
day Thursday and persist through Friday. Snow levels along I-5 will
creep as far down as 500ft this morning and again on Thursday
morning, but moderate-to-locally heavy snow will reside in the

2,000ft elevations of the OR Cascades and above 3,000ft in the WA

Cascades. Farther east, the Blue Mountains on east into the
Bitterroots and Sawtooths will be heavy snow above 3,000ft (Blues & Bitterroots) and above 4,000ft (Sawtooth). The heaviest snowfall
will unfold in the Absaroka, Tetons, Wind River, and Bear River
Ranges where they not only have the higher elevations, but also
reside where the riches 700-300mb moisture source will be and
beneath the diffluent left-exit region of a 250-500mb layer jet
streak. WPC probabilities moderate-to-high chances (40-70%) for
snowfall >12" in the peaks of these mountains ranges, as well as
the peaks of the OR Cascades. In the Willamette Valley, most
snowfall totals are likely to be less than 1", although some areas
close to Eugene, OR could eclipse 1". Expect hazardous travel
conditions in the passes of the Northern Rockies and OR Cascades
through Thursday morning.

...California...
Days 1-2...

...Heavy, disruptive snowfall for the California ranges to persist
through Thursday...

California remains ideally placed ahead of 500mb disturbances
rotating around the western flank of a large longwave trough
anchored over the western U.S.. Snow levels in northern CA are as
low as 1,000ft, down to 2,500 ft in the Sierra Nevada, and
4,000-5,000 ft in the Transverse Ranges this morning. After a day
generally upslope-driven snowfall on Wednesday, by Thursday, a
phasing of shortwaves diving southeast from the Pacific NW coast
will produce heavier snowfall totals throughout the CA mountain
ranges. Similar to the Northwest, upper ridging will provide a
break in the heavy snowfall threat beginning late Thursday and
continuing into Friday.

Additional snowfall of 1-2 feet are likely for the northern Sierra Nevada
above 3,000ft, while in the southern Sierra, elevations above 4,000
can expect several more feet in the highest elevations. The WSSI
continues to indicate widespread Major impacts are likely for just
about all of the Sierra NEvada above 4,000ft Sierra Nevada through
Thursday. This includes not only Donner Pass, but in the
Shasta/Siskiyou where Moderate to locally Major Impacts are
possible along I-5 mountain passes. In Southern California,
additional snowfall accumulations over a foot are forecast above
6,000ft in the Transverse Ranges with localized amounts exceeding 2
feet possible in the peaks of the San Gabriel and San Bernadino
Mountains through Thursday.


...Intermountain West/Southwest to the Rockies...
Days 1-3...

Pacific moisture spilling over the Cascades and Sierra-Nevada will
provide a much-needed boost to the Intermountain and Rocky Mountain
snowpack. Following a warm start, snow levels will drop into the
valleys as the leading shortwave moves inland on Wednesday. A brief
lull is expected on Thursday, except for Nevada and the Four
Corners region, where the next shortwave will bring the threat for
heavy mountain snow into Friday. Probabilities for storm total
amounts over a foot exceed 70 percent for several areas including
the high elevations of the Nevada mountains, the southern Utah
mountains, the northern Arizona plateaus to the central Mogollon
Rim, and much of the central Rockies - particularly the northern
Utah and western Colorado ranges.


...Northern Plains & Upper Great Lakes...
Days 1-2...

The winter storm is ongoing this morning with heavy snow blanketing
much of northern ND, northern MN, and into the northern tier of
MI's Upper Peninsula. Heavy snow will continue to the north of the
500mb low as it tracks across southern MN and into northwest WI,
placing the MN Arrowhead perfectly placed beneath not just the
strongest upper-level divergence, but easterly flow off Lake
Superior is upsloping into the Arrowhead. Snowfall rates of 1-2"/hr
will be common this morning and through midday but rates should
gradually weaken this afternoon and tonight. The closed low will
meander over the western MI U.P. through Thursday morning, keeping
periods of light-to-moderate snow in the forecast over northern MN
through Thursday morning. Snowfall totals of 1-2 feet are expected
in the MN Arrowhead with localized amounts surpassing 30" possible
by the time this storm concludes.

Additionally, with the pronounced WAA rotating around the surface
low, an area of freezing rain is also expected, especially from
just south of Duluth, MN eastward across northern WI and into
northern MI where the warm nose will be most prevalent while
surface temps remain sub-freezing. This sets the stage for a
freezing rain/icing event that could last over 24 hours in parts
of northern WI and northern MI. WPC probabilities are moderate-to-
high (50-80%) for at least 1/10 inch of ice, with locally more
than a quarter inch possible, most likely across the tip of
Michigan's Mitten, mainly areas east of Grand Traverse Bay.


...Northeast...
Days 1-3...

A strong surface low moving slowly across the Dakotas/Minnesota
today will remain entrenched within an elongated mid-level trough
extending into the Mid-Atlantic states. Vorticity lobes downstream
of this wave will spread northeast from the Mid-Atlantic states
into the Northeast, before getting sheared to the east as mid-level
flow becomes strongly confluent south of the secondary shortwave
energy crossing Maine and Nova Scotia. The resultant mid- level PVA
and divergence will overlap with a narrow ribbon of impressive
low-level WAA to produce a stripe of moderate-to- locally heavy
precipitation from Upstate NY through southern/central New England.

Periods of snow will unfold from the eastern shores of Lake Ontario
going east across the Tug Hill, southern tier of the Adirondacks,
and as far east as the Green and Berkshires. Snowfall totals are
most likely to range between a coating to 3", although some
localized totals topping 4" are possible in parts of the
Adirondacks and Berkshires. While the atmosphere is likely to
remain below freezing in these areas, a narrow warm- nose aloft
from I-90 in western NY on east through the Catskills, Poconos, and
even portions of southern New England are likely to see freezing
rain. The section of western NY located along and north of I90,
including the Rochester area, are most concerning when it comes to
travel impacts. WPC probabilities show high chances (>70%) for ice accumulations over one-tenth of an inch there and low-to- moderate
chances (20-50%) for totals over one- quarter inch. This area does
show the potential for Moderate Impacts (hazardous driving
conditions, closures possible) today. Farther east, most ice
amounts are likely to come in under a tenth of an inch from the
Finger Lakes on east through southern NY (not NYC proper), the
Poconos, and southern New England, but localized Minor Impacts are
denoted on the WSSI today.

Following a brief break in the action Thursday, a storm system
strengthening in the Midwest will direct a plume of 850-300mb
moisture towards the Northeast amidst increasing WAA Thursday night.
To the north, high pressure over southeast Canada is building in
with a weak CAD signature forming over the region. This sets the
stage for yet more ice from northern into the heart of the
Northeast. The Poconos, Catskills, southern Adirondacks, and
Berkshires have moderate chances (40-70%) for ice accumulations
over one-tenth of an inch, while many areas from the Lehigh Valley
on north and east into southern New England. The higher elevations
of the Poconos and Catskills could see localized ice accumulations
approach one-quarter inch. In the northern Appalachians, the
atmosphere will remain cold enough to support periods of snow that
look to fall heavily at times Friday and into Friday evening. WPC
probabilities show moderate-to- high chances (50-70%) for snowfall
totals >4" in the northern Adirondacks, Green, and White mountains
with low chances (10-40%) for localized amounts surpassing 8".


...Central Plains...
Days 1-2...

Tonight, a potent shortwave trough ejecting out of the Central
Rockies will take on a negative tilt as it heads into the Central
Plains. To the north of the 500mb vort max, strong 700mb Q-vector
confluence will focus a narrow area of strong vertical velocities,
coinciding with a pronounced TROWAL forming over the Black Hills on
east into the Sand Hills of NE early Thursday morning. Most
guidance agrees the impressive synoptic-scale support aloft (left-
exit region of a 250mb jet streak over head) and strong SErly 850mb
WAA will support heavy snowfall rates, and confidence is
increasing in the Black Hills and the Sand Hills being the hardest
hit. Latest WPC probabilities show moderate chances (40-60%) for

6" of snow in the Black Hills and Sand Hills on east along the

NE/SD border and into southeast SD. It is worth noting there are low-to-moderate chance probabilities (20-50%) for >8" of snowfall
in these areas as well. Given the strong dynamics and banding
potential, localized totals surpassing 10" cannot be ruled out.
Note that there does remain some uncertainty on the exact placement
of the heavy snow banding, but guidance is in fairly good
agreement a band of snow generating warning-level snowfall has
moderate chances (40-60%) over western NE. Residents in the
Central Plains should monitor the forecast from their local WFO
closely in the coming days. Minor snowfall accumulating of 1-4" are
possible as far west as east-central WY with some potential for
4-6" worth of snow in eastern NE to the north of the Omaha area.


Mullinax/Kleebauer/Pereira






$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 180838
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
338 AM EST Wed Feb 18 2026

Valid 12Z Wed Feb 18 2026 - 12Z Sat Feb 21 2026


...Pacific & Interior Northwest...
Days 1-2...

The longwave trough that has led to multiple days worth of
accumulating snowfall looks to continue through at least Thursday
morning before a upper level ridge pattern builds in late in the
day Thursday and persist through Friday. Snow levels along I-5 will
creep as far down as 500ft this morning and again on Thursday
morning, but moderate-to-locally heavy snow will reside in the

2,000ft elevations of the OR Cascades and above 3,000ft in the WA

Cascades. Farther east, the Blue Mountains on east into the
Bitterroots and Sawtooths will be heavy snow above 3,000ft (Blues & Bitterroots) and above 4,000ft (Sawtooth). The heaviest snowfall
will unfold in the Absaroka, Tetons, Wind River, and Bear River
Ranges where they not only have the higher elevations, but also
reside where the riches 700-300mb moisture source will be and
beneath the diffluent left-exit region of a 250-500mb layer jet
streak. WPC probabilities moderate-to-high chances (40-70%) for
snowfall >12" in the peaks of these mountains ranges, as well as
the peaks of the OR Cascades. In the Willamette Valley, most
snowfall totals are likely to be less than 1", although some areas
close to Eugene, OR could eclipse 1". Expect hazardous travel
conditions in the passes of the Northern Rockies and OR Cascades
through Thursday morning.

...California...
Days 1-2...

...Heavy, disruptive snowfall for the California ranges to persist
through Thursday...

California remains ideally placed ahead of 500mb disturbances
rotating around the western flank of a large longwave trough
anchored over the western U.S.. Snow levels in northern CA are as
low as 1,000ft, down to 2,500 ft in the Sierra Nevada, and
4,000-5,000 ft in the Transverse Ranges this morning. After a day
generally upslope-driven snowfall on Wednesday, by Thursday, a
phasing of shortwaves diving southeast from the Pacific NW coast
will produce heavier snowfall totals throughout the CA mountain
ranges. Similar to the Northwest, upper ridging will provide a
break in the heavy snowfall threat beginning late Thursday and
continuing into Friday.

Additional snowfall of 1-2 feet are likely for the northern Sierra
Nevada above 3,000ft, while in the southern Sierra, elevations
above 4,000 can expect several more feet in the highest elevations.
The WSSI continues to indicate widespread Major impacts are likely
for just about all of the Sierra NEvada above 4,000ft Sierra
Nevada through Thursday. This includes not only Donner Pass, but in
the Shasta/Siskiyou where Moderate to locally Major Impacts are
possible along I-5 mountain passes. In Southern California,
additional snowfall accumulations over a foot are forecast above
6,000ft in the Transverse Ranges with localized amounts exceeding 2
feet possible in the peaks of the San Gabriel and San Bernadino
Mountains through Thursday.


...Intermountain West/Southwest to the Rockies...
Days 1-3...

Pacific moisture spilling over the Cascades and Sierra-Nevada will
provide a much-needed boost to the Intermountain and Rocky Mountain snowpack. Following a warm start, snow levels will drop into the valleys as
the leading shortwave moves inland on Wednesday. A brief lull is
expected on Thursday, except for Nevada and the Four Corners
region, where the next shortwave will bring the threat for heavy
mountain snow into Friday. Probabilities for storm total amounts
over a foot exceed 70 percent for several areas including the high
elevations of the Nevada mountains, the southern Utah mountains,
the northern Arizona plateaus to the central Mogollon Rim, and much
of the central Rockies - particularly the northern Utah and
western Colorado ranges.


...Northern Plains & Upper Great Lakes...
Days 1-2...

The winter storm is ongoing this morning with heavy snow blanketing
much of northern ND, northern MN, and into the northern tier of
MI's Upper Peninsula. Heavy snow will continue to the north of the
500mb low as it tracks across southern MN and into northwest WI,
placing the MN Arrowhead perfectly placed beneath not just the
strongest upper-level divergence, but easterly flow off Lake
Superior is upsloping into the Arrowhead. Snowfall rates of 1-2"/hr
will be common this morning and through midday but rates should
gradually weaken this afternoon and tonight. The closed low will
meander over the western MI U.P. through Thursday morning, keeping
periods of light-to-moderate snow in the forecast over northern MN
through Thursday morning. Snowfall totals of 1-2 feet are expected
in the MN Arrowhead with localized amounts surpassing 30" possible
by the time this storm concludes.

Additionally, with the pronounced WAA rotating around the surface
low, an area of freezing rain is also expected, especially from
just south of Duluth, MN eastward across northern WI and into
northern MI where the warm nose will be most prevalent while
surface temps remain sub-freezing. This sets the stage for a
freezing rain/icing event that could last over 24 hours in parts
of northern WI and northern MI. WPC probabilities are moderate-to-
high (50-80%) for at least 1/10 inch of ice, with locally more
than a quarter inch possible, most likely across the tip of
Michigan's Mitten, mainly areas east of Grand Traverse Bay.


...Northeast...
Days 1-3...

A strong surface low moving slowly across the Dakotas/Minnesota
today will remain entrenched within an elongated mid-level trough
extending into the Mid-Atlantic states. Vorticity lobes downstream
of this wave will spread northeast from the Mid-Atlantic states
into the Northeast, before getting sheared to the east as mid-level
flow becomes strongly confluent south of the secondary shortwave
energy crossing Maine and Nova Scotia. The resultant mid- level PVA
and divergence will overlap with a narrow ribbon of impressive
low-level WAA to produce a stripe of moderate-to- locally heavy
precipitation from Upstate NY through southern/central New England.

Periods of snow will unfold from the eastern shores of Lake Ontario
going east across the Tug Hill, southern tier of the Adirondacks,
and as far east as the Green and Berkshires. Snowfall totals are
most likely to range between a coating to 3", although some
localized totals topping 4" are possible in parts of the
Adirondacks and Berkshires. While the atmosphere is likely to
remain below freezing in these areas, a narrow warm- nose aloft
from I-90 in western NY on east through the Catskills, Poconos, and
even portions of southern New England are likely to see freezing
rain. The section of western NY located along and north of I90,
including the Rochester area, are most concerning when it comes to
travel impacts. WPC probabilities show high chances (>70%) for ice accumulations over one-tenth of an inch there and low-to- moderate
chances (20-50%) for totals over one- quarter inch. This area does
show the potential for Moderate Impacts (hazardous driving
conditions, closures possible) today. Farther east, most ice
amounts are likely to come in under a tenth of an inch from the
Finger Lakes on east through southern NY (not NYC proper), the
Poconos, and southern New England, but localized Minor Impacts are
denoted on the WSSI today.

Following a brief break in the action Thursday, a storm system
strengthening in the Midwest will direct a plume of 850-300mb
moisture towards the Northeast amidst increasing WAA Thursday
night. To the north, high pressure over southeast Canada is
building in with a weak CAD signature forming over the region. This
sets the stage for yet more ice from northern into the heart of
the Northeast. The Poconos, Catskills, southern Adirondacks, and
Berkshires have moderate chances (40-70%) for ice accumulations
over one-tenth of an inch, while many areas from the Lehigh Valley
on north and east into southern New England. The higher elevations
of the Poconos and Catskills could see localized ice accumulations
approach one-quarter inch. In the northern Appalachians, the
atmosphere will remain cold enough to support periods of snow that
look to fall heavily at times Friday and into Friday evening. WPC
probabilities show moderate-to- high chances (50-70%) for snowfall
totals >4" in the northern Adirondacks, Green, and White mountains
with low chances (10-40%) for localized amounts surpassing 8".


...Central Plains...
Days 1-2...

Tonight, a potent shortwave trough ejecting out of the Central
Rockies will take on a negative tilt as it heads into the Central
Plains. To the north of the 500mb vort max, strong 700mb Q-vector
confluence will focus a narrow area of strong vertical velocities,
coinciding with a pronounced TROWAL forming over the Black Hills on
east into the Sand Hills of NE early Thursday morning. Most
guidance agrees the impressive synoptic-scale support aloft (left-
exit region of a 250mb jet streak over head) and strong SErly 850mb
WAA will support heavy snowfall rates, and confidence is
increasing in the Black Hills and the Sand Hills being the hardest
hit. Latest WPC probabilities show moderate chances (40-60%) for

6" of snow in the Black Hills and Sand Hills on east along the

NE/SD border and into southeast SD. It is worth noting there are low-to-moderate chance probabilities (20-50%) for >8" of snowfall
in these areas as well. Given the strong dynamics and banding
potential, localized totals surpassing 10" cannot be ruled out.
Note that there does remain some uncertainty on the exact placement
of the heavy snow banding, but guidance is in fairly good
agreement a band of snow generating warning-level snowfall has
moderate chances (40-60%) over western NE. Residents in the
Central Plains should monitor the forecast from their local WFO
closely in the coming days. Minor snowfall accumulating of 1-4" are
possible as far west as east-central WY with some potential for
4-6" worth of snow in eastern NE to the north of the Omaha area.


Mullinax/Kleebauer/Pereira





$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 181939
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
239 PM EST Wed Feb 18 2026

Valid 00Z Thu Feb 19 2026 - 00Z Sun Feb 22 2026


...Pacific Northwest...
Day 1...

The longwave trough responsible for the recent mountain snowfall
will continue to influence the the region through tomorrow morning.
Following this, an upper-level ridge is expected to build late
Thursday and persist into Saturday, bringing a pause to the active
pattern. Snow levels along the I-5 corridor will dip toward 500ft
again tomorrow morning, though the most impactful moderate-to-
locally heavy accumulations will remain confined to higher elevations
of the southern Washington, Oregon Cascades, and the southern
Oregon coastal ranges.

...California...
Days 1-2...

...Heavy, disruptive snowfall for the California ranges to persist
through tomorrow...

A pair of phasing shortwaves diving southeast from the Pacific
Northwest coast will support intensifying snowfall across the
California ranges tonight into tomorrow. The heavy snowfall threat
will begin to wane late tomorrow as upper-level ridging begins to
build and remains in place into the weekend.

Additional snowfall of 1-2 feet is likely for the northern Sierra
Nevada above 3,000ft, while the southern Sierra could see several
more feet above 4,000ft. The WSSI continues to indicate Major
Impacts for nearly all of the Sierra Nevada above 4,000ft through
Thursday, including Donner Pass. In the Shasta/Siskiyou region,
Moderate to locally Major impacts are possible along the I-5
passes. For Southern California, additional accumulations of a foot
or more are possible for the higher elevations of the Transverse
and northern Peninsular ranges.


...Intermountain West/Southwest to the Rockies...
Days 1-2...

Pacific moisture spilling over the Cascades and Sierra Nevada will
contribute to the Intermountain and Rocky Mountain snowpack. While
a brief lull is expected tomorrow for some areas, Nevada and the
Four Corners region will see a continued snow threat into Friday
as the next shortwave arrives. WPC Probabilities indicate that
additional snow accumulations exceeding 8in are likely (greater
than 50 percent) for the high elevations of the Nevada and
southern Utah mountains, the northern to central Arizona plateaus
(including the Mogollon Rim), the Arizona White Mountains, and the
central Rockies - specifically the northern Utah and western
Colorado ranges.


...Northern Plains & Upper Great Lakes...
Day 1...

Potent winter storm ongoing today will gradually spin eastward and
weaken by Friday morning. Around this system, heavy snow
will continue in response to impressive WAA beneath a TROWAL
across the U.P. of MI and the Arrowhead of MN, with additional
light snow persisting within an elongated inverted trough extending
into North Dakota. While additional snowfall across ND/western MN
should be light (WPC probabilities less than 10% for 4+ inches),
heavy snow will continue into the Arrowhead through Thursday
morning. This will be the axis of heaviest snow thanks to its
position beneath the TROWAL, aided by lake moisture and persistent
upslope flow into the Iron Ranges. Here, WPC probabilities are high

70%) for an additional 6 inches after 00Z this evening, bringing

storm total snowfall to more than 2 feet in some areas.


...Northeast...
Days 2-3...

A strengthening surface low moving across the Great Lakes Friday
will slow as it becomes vertically stacked beneath its associated
closed mid-level low. Downstream warm advection emerging from the
Gulf will surge a warm front northeast into the Mid-Atlantic, with
the subsequent occlusion and triple point resulting in secondary
low development near the eastern Ohio Valley/eastern Great Lakes
Friday evening. This secondary low will track only very slowly
eastward as the parent shortwave gets sheared into the more
confluent westerlies, but this mid-level westerly flow will help
translate an expanding precipitation shield eastward across the
Northeast through Saturday.

During this evolution, WAA on 850mb SW flow emerging from the Mid-
Atlantic and overrunning the surface warm front will expand the
aforementioned precipitation shield northeastward Friday and Friday
night. As this occurs, a weak high pressure will retreat, and the
antecedent airmass is marginally conducive for winter
precipitation, so precipitation may initially be rainfall,
especially for the Mid-Atlantic and into southern New England,
before transitioning to mixed and then snow, especially farther
north and east. The key thermal evolution will occur as yet a third
surface low develops well offshore New England along the warm
front/stationary front, which will help manifest a switch in wind
direction to the N/NW and subsequent cold advection to cool the
column. This will help transition precipitation to all snow from
Upstate NY through New England, and although there is some concern
about dry air near the top of the DGZ limiting snow growth, there
is expected to be sufficient ascent for moderate snowfall (briefly
heavy during the greatest fgen during the early stages of this
event Friday evening).

The heaviest snowfall is expected between 18Z Friday and 12Z
Saturday, with light snow continuing in some areas through Sunday
morning as a secondary vorticity impulse swings southward across
the area. While this will lengthen the duration of snowfall,
additional accumulations after 12Z Saturday should be relatively
light which is reflected by modest growth of the WSE plumes. While
the duration of the most intense forcing will be limited, WPC
probabilities indicate a moderate risk (50-70% chance) of at least
6 inches in the higher terrain of the Adirondacks, Greens,
Whites, and Monadnock region of NH, with widespread 4+ inches
likely (70-90%) across much of central New England and northern
Upstate NY. Locally as much as 10 inches is possible in the highest
elevations before precipitation ends by the end of the forecast
period.


...Central Plains into the Great Lakes...
Days 1-3...

A shortwave emerging from the Great Basin will amplify into a
negative tilt as it crosses the Central Rockies and into the
Central Plains late tonight into Thursday morning. This feature may
continue to deepen into a closed low as it moves over the Corn Belt
Thursday night, with the overlap of these height falls/PVA and the
LFQ of a strengthening subtropical jet streak leading to surface
cyclogenesis in the lee of the Rockies. This low will then track
E/NE towards the Great Lakes by Friday morning, with substantial
deepening possible in the favorable synoptic setup.

The guidance has trended slightly deeper with this low, with a
subtle NW jog in the track from IA to MI, but the ensembles are
very well aligned leading to high confidence in this development.
Downstream of this low, moisture will stream northward from the
Gulf, and although the highest PW anomalies (above the 90th
percentile according to NAEFS) will remain east of the region, the
accompanying theta-e ridge will rotate cyclonically back into the
system as a modest TROWAL on Thursday. At the same time, increasing
850-600mb fgen behind a cold front, and overlaid with an
impressive deformation axis NW of the surface low in response to
the deepening mid-level wave will drive ascent into the TROWAL,
suggesting an increasing potential for a band of heavy snow from
western Nebraska into the western U.P. of MI. While there is still
uncertainty into the exact placement of this narrow corridor of
heavy snowfall, this band will likely (>60% chance) contain at
least 1"/hr snowfall thanks to CSI noted in regional cross-
sections, so should accumulate rapidly despite the transient nature
of the system.

This is reflected by WPC probabilities that range from 50-90% for
4+ inches from the Pine Ridge of NE through western IA, with
locally as much as 8 inches possible (30-50%). Lighter snowfall
(10-30% chance for 4+ inches) is possible from northern IA through
the western U.P. of MI, but if the deeper trends continue these
probabilities could also shift upward, and there are already a few
WSE members showing much higher snowfall potential.

As this low pressure fills and then redevelops along an
occlusion/triple point farther east, a lingering inverted trough is
progged to drape from the center of the low back to the NW into the
U.P. of MI and Arrowhead of MN. This will drive locally enhanced
ascent into Saturday, with N/NW flow in the vicinity creating some
lake enhancement along the south shore of Lake Superior in the
U.P. of MI. Forcing for ascent generally wanes with time on D3, so
despite the cold column and deep DGZ leading to fluffy SLRs, WPC
probabilities suggest only a modest potential (30-50%) of 4+ inches
of snowfall, highest across the western U.P. of MI.


Weiss/Pereira


$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)

FOUS11 KWBC 190849
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
349 AM EST Thu Feb 19 2026

Valid 12Z Thu Feb 19 2026 - 12Z Sun Feb 22 2026


...California...
Day 1...

...Heavy, disruptive snowfall for the California ranges persists
through today...

A pair of shortwave troughs along the OR and northern CA coasts
phase this morning over northern CA and support intensifying
onshore flow and heavy snow across the Sierra Nevada, CA Cascades,
and higher SoCal ranges today. The upper trough the pushes across
NV tonight, bringing northerly/drying flow and a cut off to snow
late this evening.

Additional snowfall exceeding 1 foot is 60-90% likely along the
entirety of the Sierra Nevada chain where snow levels will around
2500ft this morning and 3000ft this afternoon. Snow levels in SoCal
rise from 3000ft ot 5000ft today before dropping to 2500ft tonight
as precip/snow cuts off.


...Intermountain West/Southwest to the Rockies...
Days 1-2...

Pacific moisture spilling over the Sierra Nevada and SoCal ranges
will spread much needed snow over the Great Basin this afternoon
and the southern Rockies tonight into Friday with snow levels of
4000 to 5000ft. Day 1 snow probs for >8" are 50-80% over the higher
NV basin ranges, 50-90% for the southern Utah ranges and the Kaibab
Plateau in northern AZ. This then translates east through the San
Juans for the Day 1.5 snow probs for >8".


...Central Plains to the northern Great Lakes...
Days 1/2...

A shortwave trough over CO this morning will continue to take on a
negative tilt today as it tracks south of a low over northern MN
and becoming a closed low over the L.P. of MI Friday morning. The
overlap of height falls/PVA and the left exit region of a
strengthening subtropical jet streak is promoting surface
cyclogenesis in the lee of the CO Rockies that tracks across KS
this morning before turning northeast to southern WI this
afternoon/evening.

Guidance tonight trended south to where the EC-AIFS has had its
main QPF streak for several runs. Increasing 850-600mb fgen behind
a cold front, and overlaid with an deformation axis NW of the
surface low in response to the deepening mid-level wave will drive
ascent into the TROWAL. The associated heavy snow has developed
over southeast WY and northeast CO which will track across Nebraska
in line with its orientation today before curving northeast over
Iowa into Wisconsin tonight and up through the U.P. Friday morning.
A narrow corridor of heavy snowfall of up to 1.5"/hr per the 00Z
HREF is expected across Nebraska into Iowa with CSI noted in
regional cross-sections.

Day 1 snow probs for >6" have risen to 50-70% over central Nebraska
and around 30% for Omaha to Des Moines. Low probs around 10% then
extend over northeast IA into southwest WI for Day 1.5. Lake
enhancement coming around the deepening low then invigorates heavy
snow over the U.P. late tonight through Friday with Day 1.5 snow
probs 30-60% for >6".


...Northeast...
Day 2...

The aforementioned mid-level low over the L.P. of MI by Friday
morning shears apart/opens over NY state Friday night though it
still has plenty of energy to translate to a coastal low off the
northern Mid-Atlantic Friday afternoon/evening. Warm air advection
precip surged north through PA/NY state and New England Friday,
pivoting east north of the developing low Friday evening.

The warm nose is less progressive in 00Z guidance, though a wintry
mix is still expected to develop over northeast PA and southern NY
early Friday with heavier snow (rates above 1"/hr per the 00Z HREF)
over the Adirondacks, Greens, and across southern NH for the
afternoon and evening. Day 2 snow probs for >6" are 40-80% over
this terrain/area. Day 1.5 ice probs for >0.25" are around 10% in
the Catskills to the Poconos. The warm nose should be strong enough
to allow a stripe of sleet accum between the ice and snow with the
progression of the warm nose key to where the southern boundary of
heaviest snow sets up.


Jackson



$$

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (1:2320/105)