Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Aug 22 2023 04:41:14 ACUS02 KWNS 220441 SWODY2 SPC AC 220439 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1139 PM CDT Mon Aug 21 2023 Valid 231200Z - 241200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY INTO WEDNESDAY NIGHT ACROSS MUCH OF LOWER MICHIGAN...PARTS OF NORTHEASTERN OHIO...NORTHWESTERN PENNSYLVANIA...WESTERN NEW YORK STATE... ....SUMMARY... Isolated to widely scattered severe storms are possible late Wednesday into Wednesday night across Lower Michigan into the Lake Erie and western Lake Ontario vicinity. ....Synopsis... Warm-core ridging will remain rather prominent across much of the nation east of the Rockies through this period, although it may undergo at least some further suppression with the center of highest mid-level heights shifting south of the lower Missouri Valley toward the southern Great Plains. The more appreciable mid-level height falls likely will be focused on the northern periphery of the ridge, but downstream of a mid-level low migrating north of the international border into the Canadian Prairies, it appears that large-scale flow will remain broadly anticyclonic into the lee of the lower Great Lakes region. In association with digging large-scale mid-level troughing offshore of the Atlantic Seaboard, a cold front may continue nosing southward to the lee of the southern Appalachians. However, a stalling segment of this front may return eastward through portions of the lower Great Lakes region and upper Ohio Valley, while advancing southward through the Upper Midwest in response to a weak migratory frontal wave. In advance of the frontal wave, seasonably moist boundary-layer air is forecast to advect across the Upper Midwest through the lower Great Lakes region. Beneath an east-southeastward advecting plume of warm elevated mixed-layer air, and moderately strong west-northwesterly mid-level flow, it appears that this will contribute to large potential instability. ....Lower Great Lakes region... In the wake of weakening early period warm advection driven convection across parts of lower Michigan, the extent and potential of any renewed thunderstorm development remains uncertain. While mixed-layer CAPE on the order of 2000-4000 J/kg may develop within the warm sector of a weak surface low migrating across Lake Michigan into Lower Michigan by early Wednesday evening, mid/upper forcing for ascent to overcome inhibition associated with the warm/dry layers aloft and support sustained thunderstorm development remains unclear. Furthermore, while nocturnal strengthening of a 30-40 kt westerly 850 mb jet may occur across central/southern Lower Michigan, stronger warm advection along/east of the warm frontal zone may become focused across southern Lake Huron into Ontario. Still, isolated sustained boundary-layer based thunderstorm development may not be out of the question by early Wednesday evening, near/east of the surface low across interior lower Michigan. If this occurs, the environment will be potentially conducive to organized severe convection, including supercells accompanied by the risk for a tornado or two, while propagating southeastward into the overnight hours. ...Kerr.. 08/22/2023 $$ = = = 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) .