Storm Prediction Center Oct 11, 2021 0600 UTC Day 2 Convective Outlook

   SPC AC 110553

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1253 AM CDT Mon Oct 11 2021

   Valid 121200Z - 131200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   OF WESTERN AND CENTRAL KANSAS AND INTO THE NORTHWESTERN OKLAHOMA
   VICINITY...

   ...SUMMARY...
   Severe thunderstorms are expected Tuesday evening/overnight across a
   region focused on the central Plains, where an all-hazards severe
   risk is anticipated.

   ...Synopsis...
   A mid-level short-wave trough crossing the Great Lakes region
   through the first half of the period will shift northeastward into
   Canada with time, ahead of a larger upper system progressing
   steadily east-northeastward across the West.  This system --
   comprised of a deep/vigorous upper low -- will likely cross the
   western Nebraska region and reach the southwestern South Dakota
   vicinity by the end of the period.

   At the surface, high pressure will prevail over the East, and will
   expand across the western states with time.  In between, a low
   initially over the Four Corners vicinity is forecast to deepen --
   and eventually occlude -- as it shifts quickly northeastward in
   tandem with the upper system.  A cold front trailing from the low
   will shift into across the High Plains during the early evening
   hours, and then across the central Plains and into central portions
   of the southern Plains through the end of the period.

   ...Portions of the central and southern Plains...
   As a strong upper system -- and associated surface low/cold front --
   advance across the southern and central Rockies through the day,
   theta-e return will be underway across the southern Plains as
   south-southeasterly warm sector flow strengthens with time.  With
   that said, current model forecasts suggest that northward moistening
   will be less aggressive, with the warm-sector boundary layer to
   remain slightly stable -- particularly north of the Kansas/Oklahoma
   border.  As such, prospects for surface-based severe weather
   (damaging wind gusts/tornadoes) appears more limited than indicated
   earlier.

   Still, given the strength of the ejecting system and associated
   deep-layer flow, and steep lapse rates aloft above the weakly stable
   boundary layer, it appears that thunderstorm development remains
   likely from parts of western Nebraska southward to the
   Oklahoma/Texas Panhandle vicinity around sunset.  As the storms
   spread quickly eastward and expand in coverage with time,
   upscale/linear growth is expected.  The result will likely be a
   rather broad area of potential for strong wind gusts, though
   intensity of the downdrafts may be muted a bit due to the
   anticipated boundary-layer stability.  Hail will also be possible,
   as will a couple of tornadoes through the evening and into the
   overnight hours.

   ..Goss.. 10/11/2021

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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z