Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Sep 24 2025 17:34:24 ACUS02 KWNS 241734 SWODY2 SPC AC 241733 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1233 PM CDT Wed Sep 24 2025 Valid 251200Z - 261200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN NEW ENGLAND TO THE SOUTHEASTERN STATES... ....SUMMARY... Scattered thunderstorms are expected from the Southeast to New England on Thursday. Isolated damaging wind gusts and a brief tornado will be possible with the strongest storms. ....Mid Atlantic into the Northeast... A broad upper low over the OH Valley will gradually devolve into a positive-tilt trough before moving eastward over the Northeast Thursday. At the surface, a weak low will traverse the St Lawrence Valley dragging a cold front the OH Valley and Appalachians. Extensive thunderstorm activity and cloud debris will likely be ongoing at the beginning of the period ahead of the front from the central Appalachians into the eastern Great Lakes. An effective warm frontal zone is forecast to develop eastward from the advancing low to across southern New England, though there remains some uncertainty how far north destabilization may occur. With widespread clouds, minimal surface heating and poor lapse rates are expected over much of the warm sector. Still, a very moist air mass with 60s to 70s F dewpoints should support some weak buoyancy (MLCAPE generally less than 1000 J/kg). Southwesterly flow aloft will favor slightly cyclonically curved hodographs with around 30-40 kt of deep-layer shear. This could support some storm organization ahead of the front into linear clusters with transient updraft rotation. Isolated damaging gusts are the most likely threat, though a brief QLCS tornado is also possible near the effective front where low-level flow is more backed. However, given the limited buoyancy and marginal storm organization, a broader severe risk appears unlikely. ....Southern Appalachians and Southeast... Several bands or loosely organized clusters of storms are likely to be ongoing at the start of the period over portions of MS/AL into GA and upstate SC ahead of the front. Some diurnal heating of the seasonably moist air mass should result in moderate buoyancy and some renewal in intensity during the afternoon. However, poor mid-level lapse rates and high PWAT values near 2 inches suggest generally weaker updrafts. Limited storm organization from 30 kt of mid-level flow suggests only sporadic damaging gust potential with water-loaded downdrafts. Somewhat greater clearing may allow for stronger surface heating and subsequent destabilization Thursday afternoon over portions of the Carolinas and southern VA. This could support more robust thunderstorm development during the afternoon. While the stronger flow aloft will likely remain displaced farther north, at least some overlap with the larger buoyancy could support a few organized multicell clusters with a locally greater damaging wind potential with strong outflow winds through Thursday evening. ....Southwest... An upper low over central CA will move over the Southwest late Thursday into D3/Friday. Cool mid-level temperatures within the low will overspread residual monsoon moisture supporting scattered to numerous thunderstorms over portion of NV, southeastern CA and AZ. Flow aloft will not be overly strong, but should increase to 30 kt overnight. This could allow for some longer-lived storms despite only modest buoyancy and. Isolated severe gusts are possible owing to the high-based nature of the storms with steep low-level lapse rates. However, the overnight timing and limited organization potential suggests the threat will be isolated. ...Lyons.. 09/24/2025 $$ = = = 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) .