Mesoscale Discussion 0727
   NWS Storm Prediction Center Norman OK
   0319 PM CDT Mon May 25 2020

   Areas affected...Texas Big Bend and Rio Grande River vicinity

   Concerning...Severe potential...Watch possible 

   Valid 252019Z - 252215Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Scattered severe storms, including supercells, are
   possible, mainly across parts of northern Coahuila through 5-7 PM
   CDT.  Some of these storms may approach areas near the Rio Grande
   River, but it is not clear that storms progressing to the east of
   the river will be able to maintain intensity, at least through early
   evening.

   DISCUSSION...Attempts at sustained deep convective development are
   underway, where low-level convergence is focused along the higher
   terrain of northern Coahuila into areas southwest of Sanderson TX. 
   This is where strong heating of a moist boundary layer (with
   lower/mid 60s F dew points) appears to be contributing to CAPE of
   2000+ J/kg in the presence of modestly steep mid-level lapse rates.

   Aided by large-scale ascent spreading across and southeast of the
   Texas Big Bend region, downstream of an approaching short wave
   trough, lingering mid-level inhibition is expected to continue to
   weaken through 22-00Z.  As it does, thunderstorms are expected to
   initiate and intensify, beneath strengthening west-northwesterly
   mid/upper flow (including 35-40 kt at 500 mb and 50-70 kt at 300
   mb).  

   Discrete supercells are likely at least initially, primarily
   accompanied by a risk for large hail.  Some of these storms will
   tend to propagate off the higher terrain toward the Rio Grande River
   vicinity, near and south-southeast of Del Rio, TX.  However, to the
   west-northwest of Cotulla, TX, less unstable updraft inflow probably
   will tend to result in weakening trends/diminishing severe weather
   potential east of the river.

   ..Kerr/Hart.. 05/25/2020

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

   ATTN...WFO...CRP...EWX...MAF...

   LAT...LON   29190245 29870285 30040207 29610074 28369996 27480058
               27770195 28590230 29190245