ACUS03 KWNS 011137
SWODY3
SPC AC 011136
Day 3 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0636 AM CDT Wed Apr 01 2026
Valid 031200Z - 041200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN
IOWA INTO NORTHERN MISSOURI...
CORRECTED FOR INCORRECT THUNDER LINE ORIENTATION
...SUMMARY...
Severe thunderstorms are expected Friday afternoon and into the
evening hours across Iowa southward into the southern Plains. Very
large hail, severe winds, and tornadoes will be possible.
...Synopsis...
Medium and long-range guidance continue to show reasonably good
alignment in the progression of an upper wave into the central CONUS
through the day Friday into early Saturday. Ahead of this wave,
robust cyclogenesis is anticipated across the central Plains along a
residual baroclinic zone that should be draped from the Plains
eastward into the OH Valley in the wake of a leading system on
Wed/Thu. Northward advection of seasonally rich low-level moisture
(dewpoints in the low 60s) ahead of the intensifying low and
attendant cold front will establish a fairly broad warm sector from
the Midwest southward into the southern Plains. Strong to severe
thunderstorms will likely develop along and ahead of the cold front
through late afternoon and early evening with a threat for all
convective hazards.
...Iowa/northern Missouri...
The most robust convective environment will likely emerge across
northern MO into southern and central IA by late Friday afternoon.
Here, strong moisture return behind a northward lifting warm front
should support MLCAPE values upwards of 2000-2500 J/kg. Strong
synoptic ascent ahead of the surface low and ejecting upper trough
will erode warm sector inhibition, and closer proximity to the upper
jet will allow for 35-45 knot effective bulk shear values nearly
orthogonal to the approaching cold front. This should favor
initially discrete cells capable of large hail as well as tornadoes
given forecast effective SRH values on the order of 200-300 m2/s2.
With time, strong frontal forcing should promote upscale growth with
an increase in the severe wind threat, though some extended-range
CAM guidance hints a line-preceding supercells within the weakly
capped warm sector (though confidence in this scenario is low).
Regardless, convection traversing the best CAPE/shear parameter
space in the region should yield a higher potential for severe
thunderstorms, warranting the introduction of 30% risk
probabilities.
...Kansas into Oklahoma...
Further south/southwest, rapid upscale growth is anticipated along a southeastward pushing cold front by late afternoon from eastern KS
into northern OK. Storm motions and deep-layer flow more parallel to
the initiating boundary may result in initially slow southeastward
propagation of the convective line, though more substantial
progression of the line is likely by early evening as the nocturnal
jet slowly strengthens. Regardless, a severe wind threat appears
likely with this activity.
...Southwest Oklahoma into Western Texas...
A dryline will likely be draped from western OK southward into
western TX. Although forcing for ascent will be weak with southward
extent, weak capping and ample diurnal heating should support at
least isolated thunderstorm development by late afternoon. While
low-level wind shear may be somewhat marginal, forecast soundings
depict elongated hodographs favorable for splitting supercells
capable of producing large to very large hail.
..Moore.. 04/01/2026
$$
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