Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Apr 26 2023 06:02:28 ACUS02 KWNS 260602 SWODY2 SPC AC 260600 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Wed Apr 26 2023 Valid 271200Z - 281200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN LOUISIANA INTO SOUTHERN ALABAMA AND THE WESTERN FLORIDA PANHANDLE... ....SUMMARY... Scattered severe storms are expected Thursday mainly from southern Louisiana into the Florida Panhandle. Damaging gusts, large hail, and a few tornadoes will all be possible. ....Synopsis... A positive-tilt upper trough will move from the southern Plains toward the lower and middle MS Valley on Thursday, with moderate midlevel southwesterlies overspreading much of the Southeast. Meanwhile, a compact shortwave trough will move quickly south/southeastward from western MT into WY, reaching the Four Corners area by 12Z Friday. Ahead of the southern trough, low-level flow will gradually veer to southerly, resulting in increased moisture return across the Gulf Coast states. A weak low will move roughly from the Arklatex to the lower OH Valley through 00Z, and into OH by 12Z Friday. A cold front (likely augmented by convective outflow) will trail southwestward from the low, and will provide a focus for scattered to numerous storms throughout the day. Southerly winds averaging around 35 kt will maintain an unstable air mass, which will combine with favorable deep-layer shear to support a severe threat, with all modes of severe possible. ....Sabine Valley eastward into western Georgia... A substantial line of storms is likely to be ongoing Thursday morning, stretching from the lower Sabine Valley into western MS. If anything, models may be too slow with this line, given historical tendencies. Upper 60s F dewpoints will surge north across LA as well as southern MS and AL, resulting in MLCAPE in excess of 2000 J/kg, the highest values being over LA. Favorable deep-layer shear, seasonably steep midlevel lapse rates and southerly flow at 850 mb should support strengthening of this convective system as it proceeds east throughout the period. In addition to damaging winds, large hail will be possible, despite the mainly linear storm mode and due to the aforementioned environmental factors. A few tornadoes cannot be ruled out, especially if portions of the line can become segmented. Isolated supercells cannot be ruled out ahead of the line as the air mass moistens and destabilizes. A corridor of higher severe probabilities could eventually be needed, dependent on storms trends Thursday morning. ....AR into western TN... Storm coverage is expected to be isolated from AR into TN, north of the primary convective system. Cold air aloft, sufficient moisture and pockets of heating may support isolated thunderstorms near the weak surface low and in association with the midlevel vorticity maximum. Effective shear around 50 kt, modest instability but weak winds in the lowest few km may support marginal hail or wind during the afternoon. ....Northern Plains... Strong surface heating and cooling aloft with the upper trough will lead to weak instability, and a steep-lapse-rate environment. Forecast soundings depict inverted-v structures which may support downdraft potential. The overall threat appears low, however, due to limited moisture. ...Jewell.. 04/26/2023 $$ = = = 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) .