Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Feb 15 2023 17:30:03 ACUS02 KWNS 151729 SWODY2 SPC AC 151728 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CST Wed Feb 15 2023 Valid 161200Z - 171200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PARTS OF MISSISSIPPI AND ALABAMA NORTHWARD INTO SOUTHWEST OHIO... ....SUMMARY... Widely scattered severe thunderstorms are likely from the central Gulf Coast states northward into the Ohio Valley on Thursday. Several tornadoes are possible over Mississippi and Alabama, including the risk for isolated strong tornadoes. ....Synopsis... An elongated positive-tilt upper trough will extend from the upper Great Lakes into the southern Plains by 00Z, with a primary/leading midlevel jet over 110 kt from MO into Lower MI and a dry slot developing from St. Louis to Lake Erie. After 00Z, a secondary wave will move from the southern Plains toward the lower MS Valley, with increasing height falls and strengthening winds aloft across the southeastern states. At the surface, low pressure will move from southern IL into OH by 00Z, reaching New England by Friday morning. A cold front will extend south from the low, crossing the MS River by late morning, and proceeding into the mid OH/TN Valleys by late afternoon. Meanwhile, a warm front will extend east from the low Thursday morning, across central IN and OH. Southerly winds across the warm sector will maintain a plume of 60s F dewpoints as far north as the surface low, with mid 60s F across the lower MS Valley. More substantial moisture will be in place over LA, with upper 60s F translating eastward across southern MS/AL and the FL Panhandle by Friday morning with the cold front roughly from western PA to FL by this time. A broad area of 40-50 kt southwesterly flow at 850 mb will exist atop the entire warm sector, enhancing low-level shear. The combination of a moist air mass and favorable shear over a large area will likely support corridors of severe storms, including a few tornadoes through the period. ....LA...MS...AL... A cold front will move into western MS and south-central LA by midday, where ample moisture will be in place. Storms both along and ahead of the front will be possible as the air mass will be uncapped, with upper 60s F dewpoints likely sufficient to support surface-based parcels. Effective SRH around 300 m2/s2 will be common along the eastern edge of the instability plume, and supercells will be possible with tornado risk. As height falls and winds aloft increase overnight, the cold front will continue to support strong to severe storms, with 50 kt flow at 850 mb and mid to upper 60s F dewpoints from southern AL into the FL Panhandle. Hodographs will be quite favorable for tornadic supercells, with the primary mitigating factor being cool/marginal boundary-layer temperatures. ....OH Valley into TN... Storms are likely to be ongoing across much of TN and KY, perhaps extending into northern MS and along the AR/MS border, within a warm advection regime beneath 50-60 kt 850 mb flow. The instability axis will be near the MS River Thursday morning, thus storms across western areas may have tornado or damaging wind potential at that time. Much will depend on existing storm modes at the beginning of the day, as heating will be limited, and outflow may both provide a focus for new development or stabilize portions of the warm sector. During the afternoon, areas of air mass recovery may occur ahead of the cold front and behind the early day storms. In addition, some of the existing storm complexes could evolve/reorganize across KY and TN. Shear profiles will strongly favor supercells with tornado threat, but little heating and ongoing precipitation may limit surface temperatures. Farther north, a dry slot should clear out much of the area around IL and northern IN, but southern IN into OH will remain sufficiently unstable for severe storms given strong shear. The area along and east of the surface low track may favor isolated supercells, assuming the surface air mass can warm into the mid 60s F. ...Jewell.. 02/15/2023 $$ = = = 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) .