Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Nov 29 2023 05:02:30 ACUS01 KWNS 290502 SWODY1 SPC AC 290500 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1100 PM CST Tue Nov 28 2023 Valid 291200Z - 301200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Scattered thunderstorm development is possible by this evening across parts of the Colorado Plateau into the southern Rockies, and across parts of the southern Great Plains overnight. The risk for severe storms still appears negligible until after daybreak Thursday. ....Synopsis... While an initially deep and elongated mid-level low over Hudson Bay may become more axisymmetric and deepen further through this period, troughing to its southeast is forecast to continue to pivot away and northeast of the Atlantic Seaboard. As it does, mid-level flow appears likely trend more zonal across and east of the Mississippi Valley, but cool to cold, dry and stable conditions across much of the East will be slow to modify. The center of the cold surface ridging is forecast to begin redeveloping across and offshore of the southern Atlantic coast, leading to a strengthening southerly return flow from the western Gulf of Mexico into southern Great Plains. Models indicate that this will be enhanced by deepening surface troughing to the lee of the southern Rockies, as a short wave trough (within a branch of westerlies emanating from the southern mid-latitude Pacific) digs inland of the central/southern California coast, through the Southwest by 12Z Thursday. While the mid-level cold core is forecast to pivot inland of the California coast during the day, low-level moistening and any potential destabilization will remain confined to areas near and offshore of southern California into northern Baja California coastal areas. However, farther inland, across parts of the Colorado Plateau into the southern Rockies, low-level warming and steepening lapse rates aided by daytime heating, may contribute to destabilization. As stronger forcing for ascent and mid-level cooling overspreads this region, in the exit region of a 70-80 kt 500 mb jet streak nosing across northern Mexico, scattered weak thunderstorm development is possible during the evening into the overnight hours. Farther downstream, models indicate that rapid low-level moisture return from the southwestern Gulf of Mexico is possible, particularly tonight as a southerly low-level jet (30-40+ kt around 850 mb) strengthens across the lower Rio Grande Valley into the southern Great Plains. North and inland of the lower Texas coast, associated destabilization will likely be rooted above at least a shallow stable surface-based layer. Across the Hill Country into northwest Texas, most unstable CAPE might increase to 500-1000 J/kg by late tonight, beneath a generally capping plume of elevated mixed-layer air. On the leading edge and northeast/east of this plume, lift associated with warm advection may support increasing thunderstorm development toward daybreak Thursday. However, weaker and weakening lapse rates within this elevated convective regime seems likely to minimize the risk for severe hail. ...Kerr/Weinman.. 11/29/2023 $$ = = = 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) .