Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Sep 19 2023 07:17:54 ACUS03 KWNS 190717 SWODY3 SPC AC 190716 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0216 AM CDT Tue Sep 19 2023 Valid 211200Z - 221200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CENTRAL AND SOUTHERN PLAINS... ....SUMMARY... At least isolated strong to severe thunderstorms are possible across portions of the Plains Thursday into Thursday night. ....Synopsis... A broad mid-level trough across the Interior West is expected to morph into an upper-level cutoff low while gradually progressing toward the Rocky Mountains on Thursday. A 500 mb speed max will translate toward the Four Corners region, encouraging a low-level mass response in the form of surface cyclogenesis across the central High Plains and incipient low-level jet development over the southern/central Plains by Thursday afternoon and evening. Low-level moisture advection beneath cooler temperatures aloft will generate sufficient instability, amid increasing deep-layer ascent, to support at least scattered thunderstorm development across the Plains. A few strong to severe storms are possible. ....Central and southern Plains... By Thursday afternoon, a surface low should form along the CO/KS border, with mid to upper 60s F surface dewpoints advecting northwestward across central portions of OK to NE. 7-8 C/km mid-level lapse rates overspreading this moisture will boost MLCAPE to 1500 J/kg, ahead of a diffuse dryline positioned over the High Plains. Though the dryline should remain quasi-stationary through the period, dynamic lift associated with the rapid approach of the aforementioned 500 mb speed max should foster scattered thunderstorm development by afternoon across parts of the central and southern Plains. 40+ kt 500 mb westerly winds, overspreading a 35-50 kt southwesterly low-level jet, will contribute to adequate wind shear for isolated multicell and supercell structures capable of mainly severe hail and wind gusts, though a tornado cannot be ruled out. By evening, one or two MCS structures may materialize owing to stronger convergence induced by the low-level jet. Should this occur, isolated severe gusts would become the dominant severe hazard. ...Squitieri.. 09/19/2023 $$ = = = 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) .