ACUS02 KWNS 200547
SWODY2
SPC AC 200546

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1246 AM CDT Sun Sep 20 2026

Valid 211200Z - 221200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE CENTRAL AND SOUTHERN APPALACHIANS...

...SUMMARY...
A few instances of damaging gusts are possible across the central
and southern Appalachians to the Lower Mississippi Valley tomorrow (Monday).

...Synopsis...
Zonal flow will dominate the upper-air pattern across the CONUS
tomorrow (Monday). Multiple mid-level low-amplitude impulses will
traverse the central CONUS as a longer wave upper trough impinges on
the CA coastline through the period. The progression of the
aforementioned impulses will encourage the southward advancement of
a surface cold front, from Texas to the central Appalachians. Given
adequate moisture and associated instability ahead of the front, a
few strong to severe storms are possible, especially over the
central and southern Appalachians.

...Central and southern Appalachians to the Lower MS Valley...
By afternoon peak heating, surface dewpoints will reach the upper
60s to low 70s F, with little to no MLCINH given a mixed boundary
layer. Across the central/southern Appalachians to the Southeast,
thunderstorms developing along and ahead of the front will have
access to 1500-2000 J/kg of tall and thin MLCAPE. Given mediocre
shear profiles, mainly pulse-cellular to multicellular complexes are
expected, the stronger of which may produce wet downbursts capable
of causing a few instances of tree/wire damage. The best chance for
wind damage will be over the central/southern Appalachians, where a
relatively greater number of storms may develop per latest
high-resolution and ML/AI guidance consensus.

...Portions of western Texas...
Along the western flank of the cold front, a couple of thunderstorms
may develop over western TX, amid a sufficiently moist low-level
airmass to support strong thunderstorms. Mid-level lapse rates
appear mediocre, and given weak upper support, no severe
probabilities were introduced this outlook despite the presence of
elongated hodographs. However, some guidance has hinted at locally
stronger multicellular storms possible. If trends continue toward
greater storm coverage, lower-end severe probabilities (mainly for
marginally severe wind/hail) may be needed in future outlooks.

..Squitieri.. 09/20/2026

$$
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