Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu May 25 2023 06:00:07 ACUS02 KWNS 250600 SWODY2 SPC AC 250558 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Thu May 25 2023 Valid 261200Z - 271200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN AND SOUTHERN HIGH PLAINS... ....SUMMARY... Severe thunderstorms are possible across the High Plains on Friday. Highest severe thunderstorm coverage is expected over eastern New Mexico and southeast Montana. ....Synopsis... Upper ridging is expected to extend from central Mexico through the Upper Midwest and Ontario early Friday morning. This ridging will be flanked on each side by upper troughing, with the western CONUS trough extending from British Columbia through southern CA and the eastern CONUS trough extending from a low over ME into the northeast Gulf. Upper pattern over the central and eastern CONUS will gradually shift towards a Rex Block while the western CONUS troughing makes modest eastward progress. At the surface, expansive ridging will cover much of the eastern CONUS while lee troughing extends throughout the High Plains. Modest low-level moisture is anticipated between these two features across the Plains/High Plains. Diurnal heating combined with low-level moisture will result in air mass destabilization throughout the High Plains, with at least scattered thunderstorm development anticipated across the majority region during the afternoon. ....Southern High Plains... Upper 50s/low 60s dewpoints are forecast across the southern High Plains by Friday afternoon. This low-level moisture beneath steep mid-level lapse rates will support moderate buoyancy, while diurnal heating contributes to air mass destabilization. Most forecast guidance suggests a low-amplitude shortwave trough will approach the region during the afternoon, interacting with the unstable air mass to support thunderstorm development. Slightly stronger mid-level flow will accompany this shortwave, helping to support 45-50 kt of 0-6 km bulk shear. This combination of buoyancy and shear will support the potential for supercells capable of all severe hazards, including very large hail and a tornado or two, during the afternoon and evening. ....Central/Northern High Plains... Warm temperatures aloft and deep boundary-layer mixing may contribute to a minimum in thunderstorm coverage across the eastern CO. Coverage is expected to increase again across eastern WY into central/eastern MT, amid cooler mid-level temperatures and improved mid-level moisture. A mostly outflow-dominant storm mode is anticipated, with some strong gusts possible. Some isolated hail is possible as well. Best overlap between buoyancy and vertical shear is currently expected over southeast MT and northeast WY, potentially fostering higher severe thunderstorm coverage than elsewhere across the region. ...Mosier.. 05/25/2023 $$ = = = 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) .