Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Mar 09 2024 13:00:30 ACUS01 KWNS 091300 SWODY1 SPC AC 091258 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0658 AM CST Sat Mar 09 2024 Valid 091300Z - 101200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF NORTHERN AND NORTHWESTERN FLORIDA TO SOUTHERN NORTH CAROLINA... ....SUMMARY... A few tornadoes and damaging to severe thunderstorm gusts are possible through early evening across parts of the Southeast States. ....Synopsis... A progressive, fairly well-amplified mid/upper-level pattern will persist through the period over the CONUS. A positively tilted shortwave trough was evident in moisture-channel imagery over parts of the Ozarks and AR to southwest TX. The eastern part will split off eastward, as a northern-stream shortwave trough digs southeastward across the upper Mississippi Valley/Great Lakes region. The southern perturbation will cross the Mid-South and Tennessee Valley regions today, reaching the southern Appalachians by 00Z as a more diffuse, elongated trough and vorticity banner within a broader area of cyclonic flow. The northern trough will develop a closed 500-mb low tonight over the Upper Great Lakes and Lower MI, contributing to a large area of cyclonic flow by 12Z over most of the East. At the surface, 11Z analysis showed a low over Lake Huron with occluded front/trough southward to another low over west-central GA. From that low, a cold front extended southwestward across the western FL Panhandle, and a warm front was drawn eastward over extreme southern SD to adjoining Atlantic waters. The southern low should ripple northeastward across central parts of SC/NC by 21Z today, with its definition muddled somewhat by convective processes just to the south and southeast. By 00Z, the low should reach northeastern VA, with cold front across the eastern Carolinas, southern GA, and the FL coastal bend, to the central/southwestern Gulf. ....Southeastern CONUS... Occasional severe thunderstorms -- within a broader area of convection described below -- will offer the greatest severe threat today, in the forms of a few tornadoes and sporadic damaging to severe gusts. An ongoing convective band was apparent across southern GA and parts of the FL Panhandle,ahead of the cold front and along and south of the warm front. See SPC tornado watch 34 and related mesoscale discussions for near-term coverage of this activity. The associated belt of relatively maximized low-level lift will remain the principal focus for continued development through the day, as it shifts eastward across the outlook area, and also, extends northeastward over parts of the Carolinas. Moisture is increasing in the proximal part of the foregoing boundary layer (inflow region), and surface dewpoints in the upper 60s to low 70s F will become common south of the activity in the next few hours -- where not already present. That, as well as cloud-muted diurnal heating, will boost preconvective MLCAPE into the 1000-1500 J/kg range, collocated with favorable deep shear (effective-shear magnitudes 60-70 kt). Low-level hodographs will remain large, even where surface flow veers somewhat to south-southwest as the low shifts eastward. The main limiting factor for even greater severe potential will be the messy, training nature of convective mode. However, embedded mesocirculations (supercells or small LEWP/bow features) will post the greatest tornado and wind threat locally. Some potential remains for development of strong-severe thunderstorms behind the initial convective band, and in a destabilizing airmass over eastern SC and southeastern NC this afternoon. While more uncertain in terms of coverage and longevity, the buoyancy/shear parameter space still looks favorable for supercell potential with any sustained convection. As such, that part of the "slight" level probabilities will be maintained for now, with yet-to-develop mesoscale trends likely influencing the threat. ...Edwards/Jewell.. 03/09/2024 $$ = = = 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) .