ZCZC SPCSWOMCD ALL
ACUS11 KWNS 011306 
SPC MCD 011306 
TXZ000-011500-

Mesoscale Discussion 0469
NWS Storm Prediction Center Norman OK
0806 AM CDT Sat May 01 2021

Areas affected...Rio Grande Valley eastward into southern Texas

Concerning...Severe potential...Watch unlikely 

Valid 011306Z - 011500Z

Probability of Watch Issuance...20 percent

SUMMARY...Storms crossing the Rio Grande may produce marginal hail
this morning, but a watch is unlikely.

DISCUSSION...Storms have increased in intensity and coverage over
northern Coahuila, with marginal MESH shown on radar. These storms
are in a rather weakly unstable air mass with only a few hundred
J/kg of MUCAPE, but are aided by cooling aloft with the upper low.
The 12Z DRT sounding shows little instability, but modifying for
observed temperatures and dewpoints to the southeast yields
sufficient instability.

Ample PWAT exists over southern TX (1.50-1.75" per GPS sensors), but
little heating is expected in the near term. However, easterly mean
winds in the low levels will aid storm-relative inflow to any
approaching cells, and may maximize updrafts despite marginal
instability. Cold temperatures aloft could support hail.

Storm evolution will continue to be monitored this morning as
conditions ahead of these storms destabilize further.

..Jewell/Edwards.. 05/01/2021

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

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

LAT...LON   29280108 29720032 29799960 29689869 29529832 29199805
            28749797 28319823 27989889 27739956 27889997 28320034
            28930077 29280108 

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