Mesoscale Discussion 0777
   NWS Storm Prediction Center Norman OK
   0624 PM CDT Thu May 27 2021

   Areas affected...Northwest Texas into the Pecos/Rio Grande Valley
   vicinity

   Concerning...Severe Thunderstorm Watch 216...

   Valid 272324Z - 280130Z

   The severe weather threat for Severe Thunderstorm Watch 216
   continues.

   SUMMARY...Widely scattered strong to severe storms, including a few
   supercells, will continue to develop through mid to late evening,
   posing a risk for large hail and strong surface gusts before
   diminishing.

   DISCUSSION...Large-scale forcing for ascent appears mostly weak, and
   likely to remain so into the evening hours, but weakening
   inhibition, due to a combination of insolation and mid-level cold
   advection, has allowed for the initiation of scattered thunderstorms
   near the dryline.  

   Along and east of the dryline, a corridor of deep boundary-layer
   mixing with sufficient moisture for large CAPE in excess of 3000
   J/kg has developed.  This has occurred in the presence of strong
   deep-layer shear, beneath 30-50+ kt southwesterly flow in the
   500-300 mb layer.  Low-level wind fields are weak, however, with
   little appreciable strengthening forecast, except perhaps in a small
   area near the Del Rio, TX vicinity.  

   Given this environment, a period of continued thunderstorm
   intensification appears probable into the 01-03Z time frame, before
   the onset of boundary-layer cooling contributes to waning
   instability.  This may include the evolution of additional isolated
   supercells, with strongest storms posing a risk for large hail, and
   eventually strong surface gusts before diminishing.

   ..Kerr.. 05/27/2021

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

   ATTN...WFO...FWD...OUN...EWX...SJT...LUB...AMA...MAF...

   LAT...LON   32790142 33290106 33870129 34600144 35150003 33149880
               31689980 30870095 30230149 29700240 30210275 31080276
               32790142