Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Aug 15 2024 19:25:21 ACUS03 KWNS 151925 SWODY3 SPC AC 151924 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0224 PM CDT Thu Aug 15 2024 Valid 171200Z - 181200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE EASTERN U.S. AND THE PACIFIC NORTHWEST... ....SUMMARY... Isolated severe thunderstorms are possible, mainly Saturday afternoon and evening, from the Lower Great Lakes to the Mid/Deep South, and separately across a portion of the Pacific Northwest. ....Lower Great Lakes to the Mid/Deep South... Much of the broad level 1-MRGL risk area has remain unchanged, with a minor expansion across parts of the Mid-South. A slow-moving mid/upper trough should continue east across the Great Lakes vicinity through early Sunday. An occluded surface cyclone over Lower MI should drift into southern ON. A weak cold front will arc to the south over the Upper OH Valley and trail southwest to west across the Mid-South to the KS-OK border area. Along this baroclinic zone, ongoing convection at 12Z Saturday appears most probable over the Ozarks to Mid-South vicinity. It is plausible this activity may intensify, perhaps aided by an attendant MCV generated on D2, as downstream diurnal destabilization occurs in parts of the Mid to Deep South. This region will lie in the gradient of mid-level flow enhancement (outside of any MCV influence) that would aid in semi-organized multicell clustering, with a threat for sporadic damaging winds. Farther north and east, deep-layer flow should be nearly unidirectional with moderate 700-500 mb westerlies. This will foster potential for multiple multicell clusters over a relatively broad warm sector across the OH Valley to the Lower Great Lakes and the Appalachians. Mid-level lapse rates will be weaker with eastern extent, and overall MLCAPE values should tend to be moderate from 1000-2500 J/kg. At least localized damaging winds will be possible across a broad swath of the eastern CONUS. Confidence remains too low at this time in highlighting more focused corridors of greater damaging wind potential. ....Pacific Northwest... A pronounced shortwave impulse, embedded within a broader mid/upper trough, should approach the northern CA and OR coast on Saturday. A strengthening mid to upper jetlet should become centered across northern CA and the Sierra NV Range. Within the exit region of this meridional flow regime, scattered late-afternoon and evening thunderstorms should be focused from south to north across the Cascade Range. While buoyancy should remain weak, steepening mid to low-level lapse rates will support a threat for a few organized high-based cells/clusters. Isolated severe wind gusts should be the main hazard. ...Grams.. 08/15/2024 $$ = = = 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) .