ACUS11 KWNS 201757
SWOMCD
SPC MCD 201756=20
LAZ000-TXZ000-202000-

Mesoscale Discussion 2273
NWS Storm Prediction Center Norman OK
1156 AM CST Mon Nov 20 2023

Areas affected...East/Southeast TX...Much of LA

Concerning...Severe potential...Tornado Watch likely=20

Valid 201756Z - 202000Z

Probability of Watch Issuance...95 percent

SUMMARY...A Tornado Watch is expected this afternoon from
east/southeast Texas into much of Louisiana, where the potential for
tornadoes, some of which could be strong, exists.

DISCUSSION...Recent surface analysis places a low over south-central
OK, with a cold front extending southward through central TX and
then more southwestward into the TX Hill Country. A warm front also
extends southeastward from this low to SHV, stretching more
east-southeastward from there across central LA into southwest MS.
Showers and isolated thunderstorms are ongoing within the warm
sector, supported by ample low-level moisture and warm-air advection
within the warm conveyor. Several attempts at more sustained
thunderstorm development have occurred farther west along the cold
front, but none have been successful thus far.

A somewhat complex convective scenario is expected to play out from east/southeast TX into central LA this afternoon. Favorable
low-level moisture will continue to advect northward ahead of the
approaching cold front (and parent upper-level trough), contributing
to air mass destabilization. Southerly/southwesterly low-level flow
will increase this afternoon as well, strengthening low-level shear
within an environment that already has favorable deep-layer shear.
The result will be an environment supportive of supercells whenever
updrafts mature. This maturation may initially be stunted by limited
buoyancy, but continued low-level moisture advection should allow
for this limitation to be overcome by the late afternoon. A corridor
of moderate buoyancy is expected from east-central TX into central
LA.=20

Supercells capable of all severe hazards, including tornadoes are
anticipated. Shear profiles suggest the potential for a strong
tornado exists, particularly near the warm front, if a more discrete
mode can be maintained. Given this potential, a Tornado Watch will
be needed across portions of the area this afternoon.

..Mosier/Gleason.. 11/20/2023

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!4m6czlUOB9QphBsusyLJULcxx5efZc8cD_NXThYUAlGXOAXxkyk0ww8XTk0hWgtEHeI9o0EKE= wJ5MF3XWt2ms_q0FE8$ for graphic product...

ATTN...WFO...JAN...LCH...SHV...HGX...FWD...

LAT...LON 30949625 31959576 32609508 32889401 32939325 32789224
32379180 31789184 30949224 30359283 30149348 30119441
30299549 30949625=20


=3D =3D =3D
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