Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Sep 06 2024 20:01:00 ACUS01 KWNS 062000 SWODY1 SPC AC 061959 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Fri Sep 06 2024 Valid 062000Z - 071200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM LAKE ERIE ACROSS MUCH OF OHIO AND INTO SOUTHEAST INDIANA AND NORTHERN KENTUCKY... ....SUMMARY... Strong to locally severe storms are possible this afternoon from Lake Erie across much of Ohio and into southeast Indiana and northern Kentucky. ....20Z Update... Minimal changes were made to the outlook, as the previous forecast remains on track. Along the front/wind shift in OH, a couple small, loosely organized clusters (with transient supercell characteristics) will be capable of producing strong to locally damaging wind gusts through the afternoon, aided by diurnally steepened low-level lapse rates. Isolated small to marginally severe hail will also be possible with this activity. Farther southwest into southeast IN, additional small clusters and weak/transient left-movers are evolving behind the wind shift. Here, slightly stronger deep-layer shear (per the latest IND VWP) could support sporadic hail and isolated strong to severe gusts. Overall, the severe threat still appears too marginal/localized for an upgrade. For additional details on the near-term severe risk, see MCD #2049. ...Weinman.. 09/06/2024 ..PREV DISCUSSION... /ISSUED 1127 AM CDT Fri Sep 06 2024/ ....Lower Great Lakes into the OH Valley... Morning satellite imagery shows a well-defined shortwave trough moving through the Upper Midwest and into the Mid MS/Lower OH Valley. This shortwave trough is expected to continue eastward/southeastward through OH Valley during the day, progressing through the base of the parent upper trough over Ontario. Recent surface analysis places the low associated with this wave over southwestern Ontario. A cold front extends southwestward from this low across the middle/lower OH Valley and the Ozark Plateau before continuing through central and southwest OK. Low-level airmass ahead of this front across much of the OH Valley is characterized by mid 60s dewpoints. This low-level moisture is forecast to advect northeastward into the Upper OH Valley in a fairly narrow corridor ahead of the front throughout the day, although boundary-layer mixing could drop dewpoints into the upper 50s by the afternoon. This low-level moisture will help support modest buoyancy as the airmass diurnally warms, although the overall buoyancy will be limited by both the boundary-layer mixing and persistence of warm mid-level temperatures. There should still be enough buoyancy to support thunderstorm development along the front during the afternoon. The stronger mid-level flow, and resultant stronger vertical shear, will lag behind the front, while also having a more front-parallel structure. This orientation, coupled with the modest buoyancy and weak pre-frontal convergence, could result in quick undercutting of any updrafts, leading to a more anafrontal character to the storms. Even so, isolated thunderstorms may remain in the warm sector long enough to produce a few damaging gusts. Isolated hail is possible as well, even as storms become displaced behind the front. Activity should weaken this evening as it moves eastward out of the most favorable moisture, and into a nocturnally cooling/stabilizing boundary layer. ....Elsewhere... Isolated to widely scattered thunderstorms are possible along the front from Mid-South vicinity across AR into northwest TX. Weak buoyancy and shear should mitigate storm intensity, keeping the severe potential low. Numerous thunderstorms are anticipated from the Gulf Coast into FL, amid the tropical airmass in place. A few water-loaded downbursts capable of damaging gusts are possible, particularly across the FL Peninsula. $$ = = = 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) .