Subj : MESO: Mesoscale Discussion 2273 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Nov 20 2023 17:57:14 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 To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .