Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Apr 20 2025 07:11:55 ACUS03 KWNS 200711 SWODY3 SPC AC 200711 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0211 AM CDT Sun Apr 20 2025 Valid 221200Z - 231200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF WESTERN/CENTRAL TEXAS...WESTERN OKLAHOMA...AND SOUTHERN KANSAS... ....SUMMARY... Isolated severe thunderstorms are possible on Tuesday across portions of the southern Plains. ....Synopsis... A low-amplitude west/southwest flow regime is expected across much of the CONUS on Tuesday. A weak upper trough will be maintained across the western U.S. while a belt of stronger westerly flow envelops the north-central and northeast U.S. where a pair of modest shortwave upper troughs will migrate east through the period. At the surface, south/southeasterly low-level flow over the Gulf and southern Plains will transport modified Gulf moisture northward across TX/OK/KS. ....Western TX/OK into southern KS... Large scale ascent is expected to remain somewhat nebulous across the region on Tuesday. However, various forecast models suggest a weak impulse may migrate across the southern Rockies into the southern Plains Tuesday afternoon into evening atop the moistening boundary layer. Modest west/southwesterly flow and strong surface heating also may allow for weak lee low development across the southern High Plains, and the development of a dryline extending from the OK/TX Panhandles southward through western TX. A stalled surface boundary is also forecast to extend across central KS. These boundaries may provide focus for isolated thunderstorm development by late afternoon. A plume of steep midlevel lapse rates will reside across the region, aiding in diurnal destabilization, with MLCAPE values around 1500-2000 J/kg possible. Additionally, forecast guidance indicates an 25-35 kt southwesterly low-level jet will develop during the evening. NAM forecast soundings suggest at least weak capping between 850-700 mb may persist, though the GFS is much more mixed with a weaker cap. Given the weak forcing regime, thunderstorm coverage remains uncertain. Nevertheless, a few organized thunderstorms during the late afternoon into the evening hours, with a risk for large hail and damaging gusts, appear possible and a Marginal (level 1 of 5) risk has been included. ...Leitman.. 04/20/2025 $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .