ACUS48 KWNS 180704
SWOD48
SPC AC 180703

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0203 AM CDT Thu Jun 18 2026

Valid 211200Z - 261200Z

...DISCUSSION...
...Day 4/Sunday - Mid-MS Valley vicinity...

A weak mid/upper shortwave trough over the Mid-MO Valley Sunday
morning across the Mid-MS and lower OH Valley regions through the
period. A surface low over the central Plains will spread east in
tandem with the upper system, though the latitude at which this
occurs is uncertain. Furthermore, an ongoing MCS could be located
somewhere across eastern NE/KS and the adjacent MO Valley Sunday
morning. How this convection evolves through the day is also
uncertain. Nevertheless, rich boundary layer moisture will be in
place across the Lower MO/Mid-MS Valley, with moderate to strong destabilization likely to the south of a surface boundary oriented
northwest to southeast across portions of the Mid-MS/Lower OH
Valleys. Some where risk appears likely, either from reinvigorated
morning convection, or from new storm development along outflow.
Given uncertainty into placement of key features, will hold off on
introducing 15 percent probabilities at this time, but areas will
likely be needed in subsequent outlooks.

...Days 5-8/Monday-Thursday - Plains to the Midwest and Southeast...

Modest west to northwesterly flow aloft will persist east of the
Rockies through much of the forecast period. Organized severe
potential is uncertain due to a lack of notable large scale forcing.
While some severe risk is likely each day, this risk will be driven
by mesoscale processes and convective evolution each day. Overall predictability is low through most of next week.

..Leitman.. 06/18/2026

= = =
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 (1:2320/107)

ACUS48 KWNS 190817
SWOD48
SPC AC 190815

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0315 AM CDT Fri Jun 19 2026

Valid 221200Z - 271200Z

...DISCUSSION...
Severe weather is possible along a frontal zone from the
Mid-Atlantic to the southern Plains on Monday. The specific areas of
threat will be defined by the locations of individual shortwave
troughs embedded within the broader cyclonic flow. These small-scale
features lack consensus at the Day 4 timeframe which precludes 15%
severe weather probabilities at this time.

By Day 5/Tuesday, some severe weather threat is possible across
portions of the central High Plains. There is decent model agreement
showing moderate northwest flow aloft across eastern Colorado and
vicinity on the eastern periphery of a western CONUS ridge. However,
there is considerable spread in moisture return among the guidance.
Should adequate moisture advect into the region, a northwest flow
severe weather event is possible in the eastern Colorado vicinity.
This will need to be monitored.

Day 6 and beyond, model spread increases which limits
predictability. Most guidance shows moderate northwesterly flow
across portions of the Plains, which would suggest continued severe
weather episodes during the extended period. However, specific days
and locations cannot be highlighted at this time due to
aforementioned predictability challenges.

..Bentley.. 06/19/2026

= = =
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 (1:2320/107)

ACUS48 KWNS 200832
SWOD48
SPC AC 200830

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0330 AM CDT Sat Jun 20 2026

Valid 231200Z - 281200Z

...DISCUSSION...
An extended period of moderate northwesterly flow across the High
Plains will lead to severe weather potential across the central High
Plains. Upslope flow amid 30 to 50 knots mid-level winds should
result in a severe weather environment, potentially on Tuesday, and particularly Wednesday and Thursday. The front will shift based on
small-scale embedded shortwave disturbances and the prior day's
convection, which will shift the location of the unstable warm
sector. This results in uncertainty regarding the location of the
threat for each day. This will continue to be monitored for
potential areas to be added later.

Ridging will slide east across the Rockies and into the Plains by
next weekend. Some severe weather threat may exist through this time
as multiple embedded shortwave troughs will be within this region as instability increases across the Plains.

While it is mostly beyond Day 8, it is worth nothing that
deterministic, ensemble, and AI guidance all indicate a strong jet
streak and mid-level trough traversing the Rockies toward the end of
next weekend and into early next week. A strong lee cyclone would
accompany this with strong instability across the Plains. There is
still uncertainty with the timing and location of the trough, but
given the agreement in this general pattern change, a substantial
severe weather threat seems possible by the end of next weekend and
early into the following week across portions of the
central/northern Plains into the Upper Midwest.

..Bentley.. 06/20/2026

= = =
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 (1:2320/107)

ACUS48 KWNS 201607
SWOD48
SPC AC 201605

Day 4-8 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
1105 AM CDT Sat Jun 20 2026

Valid 231200Z - 281200Z

CORRECTED FOR TYPO

...DISCUSSION...
An extended period of moderate northwesterly flow across the High
Plains will lead to severe weather potential across the central High
Plains. Upslope flow amid 30 to 50 knots mid-level winds should
result in a severe weather environment, potentially on Tuesday, and particularly Wednesday and Thursday. The front will shift based on
small-scale embedded shortwave disturbances and the prior day's
convection, which will shift the location of the unstable warm
sector. This results in uncertainty regarding the location of the
threat for each day. This will continue to be monitored for
potential areas to be added later.

Ridging will slide east across the Rockies and into the Plains by
next weekend. Some severe weather threat may exist through this time
as multiple embedded shortwave troughs will be within this region as instability increases across the Plains.

While it is mostly beyond Day 8, it is worth noting that
deterministic, ensemble, and AI guidance all indicate a strong jet
streak and mid-level trough traversing the Rockies toward the end of
next weekend and into early next week. A strong lee cyclone would
accompany this with strong instability across the Plains. There is
still uncertainty with the timing and location of the trough, but
given the agreement in this general pattern change, a substantial
severe weather threat seems possible by the end of next weekend and
early into the following week across portions of the
central/northern Plains into the Upper Midwest.

..Bentley.. 06/20/2026

= = =
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 (1:2320/107)

ACUS48 KWNS 210813
SWOD48
SPC AC 210811

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0311 AM CDT Sun Jun 21 2026

Valid 241200Z - 291200Z

...DISCUSSION...
...D4/Wednesday and D5/Thursday - Central High Plains...
As high pressure builds into the central/northern Plains on
Wednesday and Thursday, upslope flow will remain persistent across
eastern Colorado and eastern Wyoming. Moderate to strong instability
is expected in this area with 40 to 50 knots of west-northwesterly
flow aloft. This should result in a favorable upslope regime capable
of supercells. A relatively narrow unstable corridor should keep the
most favorable severe threat somewhat confined to the higher
elevation prairies where instability and upslope flow will be
maximized.

Friday and Saturday, ridging is forecast to translate east across
the Plains, which may lead to a relative lull in severe weather
threat. However, by Sunday and into early next week, there is a
strong signal for troughing and moderate to strong mid-level flow
across the northern Plains and into the Upper Midwest. Several days
of substantial severe weather are possible during this period.
However, at this time, the timing and amplitude of these features
make it challenging to highlight specific areas. As the evolution of
this mid-level pattern becomes more clear, severe weather
probabilities may be added in later outlooks.

..Bentley.. 06/21/2026

= = =
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 (1:2320/107)

ACUS48 KWNS 220856
SWOD48
SPC AC 220855

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0355 AM CDT Mon Jun 22 2026

Valid 251200Z - 301200Z

...DISCUSSION...
...D4/Thursday - Central/Northern High Plains...
Upslope flow will strengthen across the central/northern High Plains
on Thursday as a surface low deepens across the southern High
Plains. This, combined with a passing mid-level jet streak and
shortwave trough, should result in scattered storm development
across the High Plains. The most likely corridor will exist from
northern Colorado into eastern Wyoming and far southwestern South
Dakota where the stronger mid-level flow/forcing overspreads the
unstable warm sector.

Beyond Day 4 there will likely be multiple days with eventual severe
weather probabilities given the amplifying trough across the
Northwest and moderate mid-level flow overspreading the northern
Plains where instability will also be quite strong. However, at this
time, there is considerable uncertainty with the timing/location of
each of the mid-level shortwave troughs, and for when the core of
the jet streak associated with the Northwest CONUS low ejects into
the Plains.

Due to these uncertainties, no probabilities have been added beyond
Day 4, but eventual probabilities are anticipated in later outlooks.

..Bentley.. 06/22/2026

= = =
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 (1:2320/107)

ACUS48 KWNS 230848
SWOD48
SPC AC 230847

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0347 AM CDT Tue Jun 23 2026

Valid 261200Z - 011200Z

...DISCUSSION...
...D5/Saturday - Northern Plains...
A strong mid-level trough will move into the Northwest on Saturday
with strong mid-level flow extending around the base of this trough.
The leading edge of this stronger mid-level flow will emerge over
the northern Plains on Saturday with a lee cyclone forecast near the
MT/SD/WY border. Moderate to strong instability is forecast to
develop as mid to upper 60s dewpoints advect northward. Strong to
severe storms appear likely during the afternoon and evening as the
lead shortwave trough emerges and the low-level jet strengthens.
There is still some uncertainty with the location/timing of the lead
shortwave trough which may require some shifting of the
probabilities at a later time. However, confidence in severe weather
in the general region is high enough to add 15 percent
probabilities.

...D6/Sunday - Northern Plains Vicinity...
On Sunday, as the primary jet streak emerges across the northern
Plains, severe weather will also be possible across North Dakota and
vicinity. However, the evolution of the upper trough/jet streak is a
bit more uncertain and therefore, the area with this greater concern
is less clear. Eventual severe weather probabilities seem likely,
but will not be added until guidance comes into better agreement
regarding the upper-level pattern.

...D7/Monday - Upper Midwest...
As the mid-level trough shifts east on Monday, the stronger
mid-level flow may overspread an unstable warm sector across parts
of the Upper Midwest. Considerable uncertainty regarding the upper
trough evolution and position of the surface features preclude
inclusion of probabilities at this time.

..Bentley.. 06/23/2026

= = =
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 (1:2320/107)

ACUS48 KWNS 240844
SWOD48
SPC AC 240842

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0342 AM CDT Wed Jun 24 2026

Valid 271200Z - 021200Z

...DISCUSSION...
...D4/Saturday - Northern Plains...
A strong trough will advance into the Northwest CONUS on Saturday
with a strong mid-level jet extending from the Great Basin to the
northern Plains. A lee cyclone will develop across eastern Wyoming
into western South Dakota. Southerly flow will strengthen and advect
low to mid 60s dewpoints northward. This will lead to strong
instability by the late afternoon across the western Dakotas. There
is still some uncertainty with the evolution of the upper-level
trough which will have some impact in the timing and location of the
severe weather threat on Saturday. At this time, have confined the
15% area to where the greatest severe weather threat appears likely
Saturday afternoon/evening, but this area may need to be refined in
future outlooks.

...Day 5 and Beyond...
Severe weather will be possible across portions of the Northern
Plains into the Upper Midwest Sunday and into next week. However, predictability remains too low to highlight areas in this timeframe.
The presence of strong to very strong instability across a large
region with multiple shortwave troughs emerging from the primary
trough centered over the West will surely support severe weather
potential most days. However, probabilities for specific areas
cannot be added until the upper-level pattern becomes more clear.

..Bentley.. 06/24/2026

= = =
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 (1:2320/107)

ACUS48 KWNS 250811
SWOD48
SPC AC 250809

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0309 AM CDT Thu Jun 25 2026

Valid 281200Z - 031200Z

...DISCUSSION...
...D4/Sun - Northern Plains...
A strong mid-level jet streak is expected to round the base of the
western CONUS trough on Sunday and emerge across the northern
Plains. As this occurs, the lee cyclone across eastern Colorado will
deepen further and move northward into the northern Plains by 12Z
Monday. Continued northward moisture transport will result in strong
to very strong instability ahead of the surface low across the
northern Plains. Forecast soundings show a very favorable
environment and an uncapped airmass by evening. Forecast specifics
remain nebulous as individual shortwave troughs will impact the
timing and coverage of storms, but severe storms are possible at
some point Sunday afternoon to Sunday night across eastern North
Dakota and into northwest Minnesota.

...D5/Mon - Upper Midwest...
The primary shortwave trough and associated mid-level jet streak is
forecast to shift northeastward across the northern Plains and
toward the Upper Midwest on Monday. This will occur atop a very
unstable airmass across a broad area of the Upper Midwest. Severe
storms are possible, but the exact magnitude and extent of the
threat will become more clear once individual shortwave troughs
associated with this upper trough become better sampled.

Beyond Day 5, the upper-level pattern becomes a bit more uncertain.
Overall, a general pattern with a trough persisting over the
Northwest or northern Rockies and a ridge over the Plains or Midwest
seems most likely. However, the differences in amplitude and
location of these features limit predictability. Within this broader
pattern, severe weather will be most likely from the northern
Rockies to the northern Plains and also potentially on the eastern
periphery of the upper ridge across the Northeast. At this time,
predictability is too low to add any probability areas.

..Bentley.. 06/25/2026

= = =
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 (1:2320/107)

ACUS48 KWNS 260858
SWOD48
SPC AC 260857

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0357 AM CDT Fri Jun 26 2026

Valid 291200Z - 041200Z

...DISCUSSION...
An upper-level trough centered within the Intermountain West will
continue pivoting northeast through the northern Plains on Monday.
This feature will be fairly meridional in character. The strongest
height falls are likely to occur after 00Z within North Dakota. To
the east, an amplified upper ridge will be in place. Moisture
advection will continue in the upper Mississippi Valley given the
southerly low levels winds. Strong to extreme buoyancy is expected
to develop as a result. While this pattern does suggest potential
for severe weather, there is still uncertainty as to where the most
favorable environment will be given the influence of convection that
could occur late on Sunday night into early Monday morning. The 15%
area has been maintained this cycle given the potential for a an MCS
to develop, but modification seems likely in the coming days given
the mesoscale details that will play a large role in where severe
weather ultimately occurs.

From Tuesday onward, the strongest mid-level flow will shift into
Canada as the western upper trough becomes more broad. A large
reservoir of strong to extreme buoyancy is still forecast to be in
place underneath the ridge. While areas of severe weather are
possible, they will be highly tied to mesoscale features as larger
scale features will become more nebulous and deep-layer shear will
weaken through the remainder of the period. As a result,
predictability is reduced.

..Wendt.. 06/26/2026

= = =
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 (1:2320/107)