Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Aug 20 2023 04:39:29 ACUS02 KWNS 200439 SWODY2 SPC AC 200437 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1137 PM CDT Sat Aug 19 2023 Valid 211200Z - 221200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS MONDAY AFTERNOON ACROSS PARTS OF ARIZONA INTO SOUTH CENTRAL UTAH...AND MONDAY NIGHT ACROSS PARTS OF NORTHEASTERN MINNESOTA...NORTHERN WISCONSIN...AND WESTERN UPPER MICHIGAN... ....SUMMARY... Widely scattered strong thunderstorms may impact parts of Arizona and the Upper Midwest Monday into Monday night, and pose at least some risk for severe hail and wind. ....Synopsis... A prominent warm core ridge (including a 6000+ meter 500 mb height center over the lower Missouri Valley) appears likely to remain entrenched across much of the nation, from the Rockies into the middle and southern Atlantic Seaboard, through this period. Within broadly confluent flow around the northwestern periphery of this ridge, the sheared remnants of Hilary are forecast to accelerate from the Great Basin into the southern Canadian Prairies, downstream of a modest mid-level trough and embedded low slowly digging into the Pacific Northwest. Weaker troughing to the south of this low is also forecast to very slowly shift inland across the California coast. At the same time, in the easterlies to the south of the ridge, a modest wave may gradually migrate across portions of the northwestern Gulf of Mexico into the lower Texas coast vicinity. Northeast of the ridge, a consolidating mid-level trough appears likely to dig across New England, accompanied by a cold front advancing across much of the Northeast, into the northern Mid Atlantic coast and upper Ohio Valley by 12Z Tuesday. Moderate to large potential instability appears likely to develop across the lower Missouri Valley into lower Ohio Valley and Ozark Plateau vicinity by late Monday afternoon, to the south/west of the stalling western flank of the cold front. However, it still appears likely that mid-level inhibition and large-scale subsidence will preclude sustained thunderstorm development. ....Southwest... Within sheared, south-southeasterly deep-layer mean flow, including 30-40 kt in the 700-500 mb layer, models indicate that a narrow plume of higher moisture content will support a corridor of higher thunderstorm probabilities across south central Arizona into the Wasatch vicinity during the day Monday. Across parts of the Colorado Plateau vicinity, and particularly south of the Mogollon Rim, it appears that mixed-layer CAPE on the order of 500-1000 J/kg may contribute to vigorous thunderstorm development with at least some potential to organize and become capable of producing small to marginally severe hail and locally strong surface gusts during the afternoon and evening. ....Upper Midwest... Models continue to indicate that a corridor of strengthening lower/mid tropospheric warm advection may become a focus for thunderstorm development west and south of Lake Superior through the Upper Michigan/Wisconsin state border vicinity Monday night. Although sizable CAPE may develop in association with elevated moisture return, near the leading edge of warming and increasingly capping layers aloft, the extent to which shear in the convective layer becomes supportive of severe hail remains unclear, based on latest forecast soundings. ...Kerr.. 08/20/2023 $$ = = = 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) .