Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Aug 17 2023 05:42:13 ACUS01 KWNS 170542 SWODY1 SPC AC 170540 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1240 AM CDT Thu Aug 17 2023 Valid 171200Z - 181200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE GREAT LAKES/MIDWEST...AND OVER PARTS OF THE MID-ATLANTIC REGION... ....SUMMARY... Isolated strong to severe thunderstorms are possible across Lower Michigan and the Ohio Valley today. A couple of strong storms that could pose low-end severe risk may also evolve across eastern Pennsylvania and surrounding areas late. ....Synopsis... A vigorous upper trough is forecast to sweep east-southeastward across the Great Lakes/Midwest region today, accompanied by a surface cold front. This boundary is expected to cross the Appalachians through the second half of the period, and near the East Coast late. Meanwhile, a ridge aloft over the West is forecast to be nudged eastward by an eastern Pacific low/trough, making gradual eastward progress toward the California coast through the period. ....Portions of the Great Lakes/Midwest... Showers and thunderstorms are forecast to be ongoing/shifting southeastward across the Great Lakes region at the start of the period. Though gusty winds can be expected through midday, storms should remain sub-severe early. During the afternoon, as diurnal heating nears its peak, ample destabilization is expected to support an uptick in storm intensity. Moderately strong flow accompanying the upper system, spreading atop the surface frontal zone, will also support local storm organization. As a result, potential for a couple of strong wind gusts that may near severe levels is expected. As storms continue eastward, crossing Ohio and Lake Erie during the evening, a gradual decrease in storm intensity is expected owing to nocturnal cooling effects, with risk expected to become minimal into western Pennsylvania and adjacent portions of West Virginia. ....Parts of the Mid-Atlantic region... As the surface cold front crosses the central Appalachians during the evening, lingering/weakening convection ahead of the front may re-intensify locally, as it encounters the slightly more unstable air anticipated east of the Appalachian Crest. With increasingly strong flow aloft spreading across this region through latter stages of the period, limited/local risk for strong/gusty winds, or a brief tornado, may evolve with a couple of potentially more vigorous storms. ...Goss/Lyons.. 08/17/2023 $$ = = = 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) .