Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Sep 20 2025 17:31:24 ACUS02 KWNS 201731 SWODY2 SPC AC 201729 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS...THE MIDDLE MISSOURI VALLEY...AND THE OHIO VALLEY INTO THE GREAT LAKES... ....SUMMARY... Isolated severe thunderstorms are possible across parts of north Texas and the Middle Missouri Valley, with the main risk being large hail. A few strong to severe thunderstorms capable of locally damaging gusts are possible across parts of the Ohio Valley into the Great Lakes. ....North Texas... Convection will likely be ongoing across southwest OK into western north TX at the start of the forecast period, which should lay out an outflow boundary across parts of north TX. Along/south of the outflow boundary and to the east of a lee trough/dryline feature, boundary-layer moisture advection and ample diurnal heating beneath relatively steep midlevel lapse rates will contribute to strong surface-based buoyancy and minimal inhibition by the afternoon. Aided by a glancing midlevel wave and related jet streak crossing western OK, isolated to widely scattered thunderstorms are expected near the lee trough and residual outflow boundary during the afternoon. A long/straight hodograph (around 40-50 kt of effective shear) and the aforementioned buoyancy should promote a couple splitting supercell structures, posing a risk of large hail. Severe wind gusts will also be possible, especially with any convective clustering that occurs with southeastward extent. ....Ohio Valley and Great Lakes... Downstream of a midlevel trough moving across the Upper MS Valley, broad/enhanced midlevel southwesterly flow will overspread a weak to moderately unstable and uncapped warm sector extending from the OH Valley into the Great Lakes. Potentially aided by a convectively augmented midlevel impulse moving into the Lower OH Valley, widely scattered thunderstorms are expected during the afternoon. Around 20-25 kt of effective shear and a warm/moist PBL will favor a few loosely organized multicell clusters, capable of producing locally damaging gusts through the afternoon. ....Middle Missouri Valley... Within the base of a midlevel trough over the Upper MS Valley, isolated thunderstorms should develop near a weak surface low near southeast SD. While boundary-layer moisture will be limited, cold temperatures aloft/steep lapse rates and sufficient buoyancy should support a couple loosely organized cells. Marginally severe hail will be possible with the stronger storms that evolve during the evening into overnight hours. ...Weinman.. 09/20/2025 $$ = = = 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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .