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

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z