Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jan 12 2023 12:22:54 ACUS01 KWNS 121222 SWODY1 SPC AC 121221 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0621 AM CST Thu Jan 12 2023 Valid 121300Z - 131200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THROUGH THIS EVENING FROM CENTRAL AL INTO NORTH GA... ....SUMMARY... Severe thunderstorms are expected today across portions of the Tennessee Valley into the Southeast. Several damaging wind gusts are likely, though occasional bouts of large hail and at least a few tornadoes are also possible. ....TN Valley/Southeast through early tonight... Downstream from a building midlevel ridge over the Rockies, some amplification of eastern CONUS troughing is expected through early Friday. Within the larger-scale trough, an embedded shortwave will continue generally eastward from the Mid-South this morning to the southern Appalachians by early tonight. An associated surface cyclone will develop east-northeastward along the OH River today, and will reach northeast PA and NY by the end of the period. South of the cyclone, a cold front will progress eastward across MS/AL/TN during the day to the Carolinas overnight. The primary severe-storm threat will focus just ahead of the cold front through this evening. Storms are ongoing this morning in two primary bands - one from western into northern KY, and another that is developing across west central into northeast MS. The northern band of convection is tied to the stronger forcing for ascent with the primary midlevel trough and surface cyclone on the north edge of the warm sector, and this convection will likely persist through the day across KY with occasional supercells/embedded bows and attendant threats for large hail, damaging winds, and a brief tornado or two. Farther south, the primary severe threat today is expected to evolve from the storms forming in MS this morning. This convection is aligned along the leading edge of the baroclinic zone near 700 mb, which is currently ahead of the remnant lee trough/cold front. Storms in this corridor will likely increase through the day in response to continued moisture advection from the south and surface heating in cloud breaks. Moderate buoyancy (MLCAPE of 1000-1500 J/kg), strong deep-layer shear/long hodographs, and some low-level hodograph curvature (effective SRH in excess of 200 m2/s2) will favor a mix of supercells and bowing segments in a band a little ahead of the surface cold front through the afternoon. Damaging winds will be the most common threat, and semi-discrete supercells in the band will pose the threat for tornadoes, along with embedded circulations in line segments. The stronger storms in the band will also be capable of producing large hail, generally in the 1-1.5 inch diameter range. The storms will spread eastward across GA and into the Piedmont of the Carolinas by early tonight, before weakening as the convection outpaces the unstable warm sector. ...Thompson/Jewell.. 01/12/2023 $$ = = = 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) .