Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Mar 14 2023 07:29:51 ACUS03 KWNS 140729 SWODY3 SPC AC 140728 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Tue Mar 14 2023 Valid 161200Z - 171200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN PLAINS INTO THE ARKLATEX... ....SUMMARY... Scattered severe thunderstorms capable of producing large hail, damaging winds, and a few tornadoes should occur Thursday across parts of the southern Plains into the ArkLaTex and lower Mississippi Valley. ....Southern Plains into the Lower Mississippi Valley... Upper troughing will progress eastward across the central CONUS on Thursday. The northern portion of this upper trough should evolve into a closed upper low over the northern Plains and adjacent parts of central Canada through the period. Farther south, a lead low-amplitude shortwave trough should quickly eject northeastward through the day from the southern Plains into the MS Valley and Midwest. Behind this lead wave, another shortwave trough with associated strong mid/upper-level west-southwesterly jet is forecast to overspread parts of TX/OK by late Thursday afternoon. There are still notable differences in deterministic guidance regarding the amplitude and location of this second shortwave trough by late Thursday afternoon. The primary surface low, initially near the KS/OK border, should develop northeastward towards the Midwest/Great Lakes by Thursday evening in tandem with the lead shortwave trough. An attendant cold front will sweep quickly southeastward over the central/southern Plains and ArkLaTex region. A dryline should mix eastward across central TX through Thursday afternoon. There are some indications in guidance that convection may initiate fairly early in the day over the open warm sector of east TX and vicinity. This activity may be tied to persistent low-level warm advection, and the glancing influence of the lead shortwave trough. Gradually increasing low-level moisture and filtered diurnal heating should support the development of at least weak instability across these areas. With strong deep-layer shear expected, any thunderstorms that be sustained could pose some severe threat. Additional isolated convection will probably develop along the dryline by late Thursday afternoon across parts of north/central TX as the second shortwave trough approaches the southern Plains. This activity may initially be supercellular with a threat for large hail given steep mid-level lapse rates and potentially moderate instability. With time, convection will likely grow upscale into an MCS along the quickly advancing cold front. This MCS should have a greater wind threat as it moves generally east-southeastward Thursday evening/overnight across central/east TX, the ArkLaTex, and eventually lower MS Valley. A rather strong low-level jet should also be present over east TX into AR/LA Thursday evening. With ample low-level shear forecast, any supercells that can form and remain ahead of the cold front/MCS should pose a tornado threat. ...Gleason.. 03/14/2023 $$ = = = 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) .