Mesoscale Discussion 0862
   NWS Storm Prediction Center Norman OK
   1059 PM CDT Mon May 20 2024

   Areas affected...parts of northeastern Colorado...northwestern
   Kansas...southwestern Nebraska

   Concerning...Tornado Watch 269...273...

   Valid 210359Z - 210600Z

   The severe weather threat for Tornado Watch 269, 273 continues.

   SUMMARY...Supercells will continue to pose a risk for large hail,
   locally damaging wind gusts and perhaps a tornado or two during the
   couple of hours, before storms evolve into a more organized cluster
   with potential for more widespread severe gusts perhaps occasionally
   in excess of 75 mph as early as Midnight-2 AM CDT.  Additional
   severe weather watches will likely be needed downstream later
   tonight.

   DISCUSSION...Several sustained discrete supercells have evolved in a
   developing cluster focused within strong warm advection centered
   around the 700 mb level.  This forcing is forecast to continue
   slowly developing eastward across the western Kansas/Nebraska border
   area through 05-07Z.  Moistening easterly low-level flow beneath
   this regime (including mid/upper 60s surface dew points advecting
   across and east of the McCook NE/Hill City KS vicinities) will
   continue to support increasingly unstable updraft inflow (including
   CAPE possibly in excess of 2000-3000 J/kg).  As this occurs,
   substantive further upscale growth and organization seems likely in
   the presence of strong deep-layer shear. 

   While storm motions are initially slow in the presence of modest
   southwesterly  deep-layer mean flow, which may have weakened some
   this evening, convective evolution during the next few hours
   probably will include the development of an increasingly
   well-defined mesoscale convective vortex.  Intensifying rear inflow
   to the south and southeast of this feature is expected to eventually
   contribute to a more rapid forward propagation and increasing
   potential for severe surface gusts.

   ..Kerr.. 05/21/2024

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...LBF...GLD...BOU...

   LAT...LON   40780197 40910110 40900053 39990031 39820136 39690196
               39450294 40160315 40780197