Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Nov 21 2023 05:51:46 ACUS01 KWNS 210551 SWODY1 SPC AC 210550 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CST Mon Nov 20 2023 Valid 211200Z - 221200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF SOUTHERN ALABAMA AND THE WESTERN FLORIDA PANHANDLE AND SOUTHWEST GEORGIA... ....SUMMARY... A few tornadoes are possible across south Alabama and the Florida Panhandle, mainly during the morning into the afternoon. The potential for locally damaging winds and a couple brief tornadoes will shift farther north and east this afternoon into early morning Wednesday across most of Georgia, the Carolinas, and far southern Virginia. ....Southeastern US... Latest satellite imagery suggests center of upper low is located near JLN. This feature is forecast to eventually dig southeast toward the mid-South as a secondary 500mb speed max translates southeast across eastern OK into southern AR by the end of the period. Immediately downstream, a corridor of strong midlevel flow will extend across the lower MS Valley into the middle Atlantic. 00z model guidance suggests modest height falls will develop ahead of this trough with values approaching 90m in 12hr, especially across the northern middle Atlantic region. In response to this trough, a weak surface low will advance across the OH Valley into southeast lower MI by late afternoon; however, a secondary surface low should evolve along the southern fringe of the Appalachians then track northeast into the Delmarva by 22/12z. This secondary surface low will prove instrumental in allowing modified air mass to advance across the Carolinas during the latter half of the period, with even weak buoyancy likely developing farther north during the overnight hours. Late this evening, an extensive corridor of deep convection has evolved within a strongly diffluent high-level flow regime from western AL-southern MS-southeast LA-western Gulf Basin. This corridor should progress steadily east through sunrise and likely extend across much of AL into the MS delta region by the start of the period. Strong deep-layer flow/shear will support organized convection, and embedded supercells are likely along this band. Forecast soundings at the start of the period exhibit MLCAPE in excess of 500 J/kg within a very moist and poor-lapse rate-environment. NAM soundings for PNS and GZH at 12z display 0-3km SRH between 400-700 m2/s2. Large-scale forcing should encourage an organized band of convection to migrate east, but this activity should weaken a bit downstream as it encounters less buoyancy and weaker forcing over northern FL/southeast GA. During the latter half of the period, primarily after 06z, boundary-layer recovery is expected across coastal Carolinas such that buoyancy will become more supportive of deep updrafts. Strong shear will favor organized convection, along with some supercell potential. Forecast soundings are quite moist with poor lapse rates through 9km. This will limit instability but isolated damaging winds and/or a tornado seem possible with this activity. ...Darrow/Lyons.. 11/21/2023 $$ = = = 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) .