Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Mar 21 2024 04:52:14 ACUS02 KWNS 210452 SWODY2 SPC AC 210450 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CDT Wed Mar 20 2024 Valid 221200Z - 231200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FRIDAY THROUGH FRIDAY NIGHT NEAR THE NORTHEASTERN GULF COAST AND ACROSS PARTS OF SOUTHERN FLORIDA AND THE FLORIDA KEYS... ....SUMMARY... One or two clusters of strong thunderstorms may impact portions of southern Florida and the Keys Friday into Friday evening, accompanied by at least some risk for damaging winds and a tornado or two. More isolated strong to severe thunderstorm development may impact northeastern Gulf coastal areas into Friday night. ....Synopsis... It appears that blocking centered over the northeastern Pacific will generally persist through this period, but guidance continues to indicate at least some weakening, as a more progressive regime gradually develops across the central toward eastern mid-latitude Pacific. There remains variability within and among the model output concerning the extent of this weakening, and the eastward acceleration of an associated mid-level low toward the northern U.S. Pacific coast. This may have at least some impact on downstream synoptic developments within the broadly confluent split flow across North America. In the higher-latitude branch, one significant occluding cyclone is forecast to continue migrating northeast and east of the Canadian Maritimes. An elongating upstream cyclonic circulation may become quasi-stationary near the southwestern shores of Hudson Bay, with a series of lower amplitude perturbations digging to its west through south, across the international border. In lower levels, the leading edge of another significant cold intrusion is forecast to nose as far south as the Texas Panhandle and Red River vicinity, and as far east as the lower Great Lakes and Ohio Valley by 12Z Saturday. In lower latitudes, mid-level troughing is still forecast to progress slowly across and east of the lower Mississippi Valley and north central Gulf of Mexico. One smaller-scale perturbation may emerge from its base and become increasingly sheared across and to the east of the southern Appalachians, while another digs across the northwestern through north central Gulf of Mexico by late Friday night. Models continue to differ concerning these features, and the larger-scale troughing will be preceded by a subtropical perturbation which is likely to be in the process of progressing into and across the Florida peninsula by early Friday. It does appear that a broad area of deepening surface low pressure will develop northeastward across much of the eastern Gulf and South Atlantic Coast states. However, sizable spread is evident within the model output concerning sub-synoptic through convective-scale developments across the Southeast, Gulf of Mexico and offshore Atlantic. ....Southeast... Even with the aforementioned uncertainties, it does appear that an initially dry/potentially cool low-level environment, across much of the Florida peninsula through eastern Gulf Coast region, will tend to maintain generally stable conditions inland of coastal areas as initial convection supported by warm advection overspreads it. However, based on various model output, including some convection-allowing guidance, there appears potential for at least one initially organized convective cluster to overspread the Florida Keys/southern Florida peninsula vicinity, coincident with a warm front off the southeastern Gulf of Mexico early Friday. Given sufficient boundary-layer destabilization in the presence of strong deep-layer shear, this may be accompanied by a risk for damaging wind gusts and perhaps a tornado or two. Thereafter, it appears that widespread convective development, perhaps including organizing clusters, may continue along trailing convective outflow gradually advancing across and east-southeast of the southeastern Gulf of Mexico through early Saturday. Convective potential to the north of this outflow remains unclear. However, models do indicate that substantive boundary-layer destabilization is possible across much of the northeastern Gulf of Mexico by late Friday night, ahead of a weak southeastward advancing cold front. Still ahead of the mid-level troughing axis, this environment may support additional scattered strong thunderstorm development which might spread inland across coastal areas before weakening. ...Kerr.. 03/21/2024 $$ = = = 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) .