669
ACUS01 KWNS 270554
SWODY1
SPC AC 270552

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1252 AM CDT Sun Sep 27 2026

Valid 271200Z - 281200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
CENTRAL AND NORTHERN HIGH PLAINS...

...SUMMARY...
Isolated thunderstorms capable of large hail will be possible across
portions of western Nebraska and the Black Hills of South Dakota.

... Synopsis ...

The midlevel pattern across the CONUS today will feature a nearly
stationary occluding cyclone southeast of Long Island, broad
anticyclonic flow across the middle of the country, and a deep
trough moving into northern and central California. Additionally, a
subtle vorticity maxima is forecast to lift quickly from near the
southern California coast toward the northern Plains.


... Portions of the Central and Northern High Plains ...

Diurnal heating of a seasonably moist airmass will result in between
1000-2000 J/kg of SBCAPE during the afternoon. The atmosphere is
likely to be capped during the afternoon, although an isolated
thunderstorm or two are possible. Large hail and strong thunderstorm
winds will be possible with any surface-based thunderstorms that do
develop. During the evening, thunderstorm coverage may increase in
response to increasing large-scale ascent associated with the
approaching subtle vorticity maxima and an increase in the low-level
jet. Large hail will be possible with the strongest of these storms.

..Marsh.. 09/27/2026

$$