Mesoscale Discussion 0711
   NWS Storm Prediction Center Norman OK
   0257 PM CDT Sun May 23 2021

   Areas affected...Parts of northeastern Colorado and southeastern
   Wyoming into southwestern South Dakota...the Nebraska Panhandle and
   northwestern Kansas

   Concerning...Tornado Watch 196...

   Valid 231957Z - 232200Z

   The severe weather threat for Tornado Watch 196 continues.

   SUMMARY...Thunderstorms are expected to continue to increase in
   coverage through late afternoon.  This may be accompanied by
   continuing risk for large hail and tornadoes, but it appears that
   activity will begin consolidating into an organizing, northeastward
   and eastward advancing cluster with strong surface gusts becoming
   the more prominent hazard by 4-5 PM MDT.

   DISCUSSION...Scattered strong to severe thunderstorm development is
   ongoing, particularly within deepening surface troughing near/just
   west of the Wyoming/Nebraska border, southward to near Limon, CO. 
   This is occurring in the presence of an increasingly less inhibited,
   moist boundary-layer characterized by moderately large CAPE of
   1000-2000 J/kg, and strong deep-layer vertical shear.

   As the southeastern-most vigorous mid-level perturbation (within
   larger-scale mid-level troughing emerging from the Intermountain
   West) gradually accelerates north-northeastward across the Front
   Range through 21-23Z, a substantive further increase in thunderstorm
   development appears likely.  A convective outflow generated or
   enhanced surface front already appears to be surging east of the
   Laramie Mountains.  As convection continues to increase, steepening
   lower/mid tropospheric lapse rates may support strengthen outflows,
   which probably will begin to consolidate and contribute to an
   upscale growing and organizing convective system.  This should tend
   to propagate north-northeastward and eastward with increasing
   potential for strong surface gusts by early evening.

   ..Kerr.. 05/23/2021

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

   ATTN...WFO...LBF...UNR...GLD...BOU...CYS...

   LAT...LON   43960330 42790207 40090190 38970288 38920324 40010383
               42370420 43960330