Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jan 12 2023 20:01:58 ACUS01 KWNS 122001 SWODY1 SPC AC 122000 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0200 PM CST Thu Jan 12 2023 Valid 122000Z - 131200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF SOUTH-CENTRAL ALABAMA NORTHEASTWARD TO THE NORTHEASTERN GEORGIA VICINITY... ....SUMMARY... Severe thunderstorms will continue across portions of the Tennessee Valley and the Southeast this afternoon and evening. A couple of damaging tornadoes, along with damaging wind gusts, remain likely, along with hail. ....Discussion... Several adjustments to the ongoing outlook areas have been made -- largely to bring the areas in line with convective progression that has occurred since the prior outlook issuance. The main change of significance, however, has been to add a significant tornado area from south-central Alabama into west-central Georgia. Within this corridor, risk for a couple of strong tornadoes -- which is ongoing at this time over parts of south-central and eastern Alabama -- will continue over the next several hours. Elsewhere, severe risk has diminished across northern fringes of the prior outlook, where the airmass has substantially stabilized to prior convective overturning and the eastward advance of the surface low/cold front across the mid Ohio Valley and adjacent central Kentucky. ...Goss.. 01/12/2023 ..PREV DISCUSSION... /ISSUED 1056 AM CST Thu Jan 12 2023/ ....Tennessee Valley/Southeast States... A wavy/modestly broken quasi-linear line of strong/severe convection extends from eastern Tennessee southwestward into northeast/central Alabama and into southeast Mississippi, with much of it effectively ahead of a cold front. Surface dewpoints are commonly in the low 60s F and this will continue to adequately support severe-caliber storms in the presence of relatively cool mid-level temperatures and relatively steep mid-level lapse rates. This is well-represented by a special 15z observed sounding from Birmingham AL. A mixed convective mode is expected to persist regionally, although somewhat more discrete storms are more viable across central/southern Alabama and southeast Mississippi/Florida Panhandle owing to cloud breaks and more modest forcing for ascent. 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 support this mix of supercells and bowing segments. 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 storms will spread eastward into/across Georgia and into the Piedmont of the Carolinas this evening, before weakening as the convection outpaces the unstable warm sector. ....Kentucky/Lower Ohio Valley into western/northern Tennessee... The fast-moving convective line from earlier this morning has largely diminished in intensity as it moved into a more stable air mass toward the Ohio/West Virginia border. While semi-plentiful/multiple corridors of convection will tend to further hinder destabilization, a pre-frontal reservoir of instability could influence additional severe storm development particularly across southern/eastern Kentucky into western/middle Tennessee this afternoon. $$ = = = 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) .