ZCZC SPCSWOMCD ALL
ACUS11 KWNS 140541 
SPC MCD 140541 
LAZ000-TXZ000-140815-

Mesoscale Discussion 1742
NWS Storm Prediction Center Norman OK
1241 AM CDT Tue Sep 14 2021

Areas affected...Upper Coast of TX...far southwest LA

Concerning...Severe potential...Watch unlikely 

Valid 140541Z - 140815Z

Probability of Watch Issuance...20 percent

SUMMARY...Weak/transient mini supercells are possible overnight near
the immediate coast of adjacent parts of the TX/LA coast.  A
weak/brief tornado cannot be ruled out, but the overall magnitude
and coverage of the risk will likely preclude a tornado watch
issuance overnight.

DISCUSSION...Hurricane Nicholas is near the TX coast with several
convective bands embedded within a heavy rain shield per radar
mosaic imagery.  KHGX and KLCH 88D VAD show enlarged hodographs
conditionally supporting mesocyclone development.  Surface
temperatures have warmed into the upper 70s to near 80 deg F during
the past couple of hours near the mouth of the Sabine River and
dewpoints are currently in the upper 70s.  It appears a narrow
tongue of modest buoyancy has begun to infiltrate the immediate
coast near the TX/LA border with around 250 J/kg MLCAPE according to
modified RAP forecast soundings.  Given the weak buoyancy/strong SRH
setup, occasional mini supercell development within the rain shield
is expected to continue near the TX/LA border for at least the next
several hours.  Accompanying the strongest circulations could be a
weak/brief tornado.  However, the overall expected magnitude of the
tornado risk and associated coverage, will probably preclude a
tornado watch issuance.  Convective trends will continue to be
monitored.

..Smith/Guyer.. 09/14/2021

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

ATTN...WFO...LCH...HGX...

LAT...LON   29569439 29889425 30029319 29579222 28609229 28759333
            28739399 29569439 

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