Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Nov 28 2024 12:40:28 ACUS01 KWNS 281240 SWODY1 SPC AC 281239 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0639 AM CST Thu Nov 28 2024 Valid 281300Z - 291200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHEAST U.S.... ....SUMMARY... A few strong to potentially severe thunderstorms are possible today across parts of the Southeast. ....Synopsis... In mid/upper levels, a couple slow-moving cyclones -- over SK and the James Bay region of eastern Canada -- will anchor a broad area of cyclonic flow that will cover most of the CONUS east of the Rockies. Embedded within that flow belt is a positively tilted shortwave trough, evident in moisture-channel imagery from southern OH to the Ozarks. Today, this feature should move quickly eastward and northeastward while elongating, and should extend from New England to the Delmarva Peninsula and NC/VA border region by 00Z, before ejecting offshore. At the surface, a cold front was drawn at 11Z from western WV over northwestern GA, central AL, southern MS, southwestern LA, and TC coastal shelf waters to deep south TX. This front should proceed eastward and southeastward today, reaching a 00Z position near an HSE-CHS-TLH line and southwestward across the Gulf. By the end of the period, the front should be offshore from all but central FL. ....Southeastern CONUS... An ongoing band of convection, with widely scattered to scattered embedded thunderstorms, was noted mainly ahead of the cold front, from western SC to southern MS. This activity should proceed eastward over the outlook area through the day, with isolated damaging gusts, hail near severe limits possible. A brief tornado or two may occur, conditional on storm-scale processes and local convective interactions. The shortwave trough and associated DCVA will remain north of the outlook area and behind the surface cold front, substantially limiting large-scale support outside very subtle height falls that may extend southward to near a MGM-MCN-CHS line. With the strongest isallobaric forcing located well north/northeast of the area (and moving away), warm-sector surface winds that are not already west- southwesterly should veer that way with time, limiting low-level convergence/lift. This casts considerable uncertainty on convective coverage and duration -- especially in the free warm sector. However, sufficiently strong midlevel flow will remain to yield favorable deep speed shear for any activity that can mature enough to take advantage. Lengthy low-level hodographs with some curvature should remain ahead of the front, even as the hodographs as a whole veer clockwise with respect to the origin. This should yield 100- 200 J/kg SRH in the lowest km, and effective SRH increasing from south to north, with peak values near 300 J/kg. Peak/preconvective MLCAPE should reach 1000-1500 J/kg from the Gulf Coast to parts of SC, diminishing northeastward substantially from there. The overall severe threat should diminish this evening and tonight as lift and instability both weaken, and the hodograph-stretching LLJ pulls away across Atlantic waters. ...Edwards/Leitman.. 11/28/2024 $$ = = = 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) .