SPC AC 111603

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1103 AM CDT Sun Sep 11 2022

   Valid 111630Z - 121200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Severe-thunderstorm potential appears minimal today and tonight.

   ...Synopsis...
   Mid-morning surface observations and satellite imagery clearly show
   the east/southeastward progression of a cold front into the MS River
   Valley. Modest cold advection following this front will continue to
   drive weak height falls aloft over the central CONUS over the next
   24 hours, leading to a gradual deepening of the upper wave over the
   Midwest. Surface analyses also show the front surging relatively
   faster across the lower MS River Valley/eastern southern Plains
   compared to locations closer to the surface low over southern Lake
   Michigan. This suggests that the occlusion process has likely begun
   and will continue through the day. Despite this, the amplification
   of the upper air regime will support gradual deepening of the nearly
   stationary surface low over northeast IL through tonight.
   Thunderstorms have already begun to develop along the cold front,
   and will expand in coverage through the afternoon hours as the front
   pushes east through the OH Valley region. Across the northern Gulf
   coast, a decaying cut-off low will migrate east/northeast through
   the day. Ample moisture advection associated with this feature
   combined with weak/broad ascent and areas of daytime
   heating/surface-based destabilization will support another day of
   scattered thunderstorms from FL northward to the Mid-Atlantic coast.
   Unseasonably high moisture associated with the remnants of Tropical
   Storm Kay will continue to foster thunderstorm chances across a
   broad area of the Southwest today. Stronger wind gusts are possible
   with any thunderstorm moving into a well-mixed region, but weak flow
   aloft will limit the probability of numerous severe gusts. 

   ...Middle OH River Valley..
   Morning RAOBs ahead of the cold front across the OH River Valley
   show ample boundary-layer moisture, but weak low and mid-level lapse
   rates. Extensive cloud cover will likely hinder surface-based
   destabilization for much of the day. However, evidence of elevated
   instability with limited inhibition is noted in observed and
   forecast soundings, as well as latest satellite trends. The
   deepening of the upper low will support increasing flow and
   elongating hodographs above 3 km through the day, which may provide
   adequate effective shear for a few stronger, more organized cells or
   clusters. If storms can become rooted within the boundary, a few
   strong wind gusts may occur. This will be most likely for areas that
   can see surface temperatures warm through the mid/upper 70s, but
   confidence in a sufficiently widespread severe risk remains too
   limited to introduce probabilities.

   ..Moore/Hart.. 09/11/2022

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z