Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat May 20 2023 05:49:21 ACUS02 KWNS 200549 SWODY2 SPC AC 200547 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Sat May 20 2023 Valid 211200Z - 221200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTH-CENTRAL OREGON INTO FAR EASTERN WA...NORTHERN ID...AND FAR WESTERN MT... ....SUMMARY... Isolated severe thunderstorms are are possible from south-central Oregon into far eastern Washington, northern Idaho, and far western Montana Sunday afternoon and evening. ....Synopsis... The upper pattern across the CONUS will be characterized by predominantly weak flow early Sunday morning, with ridging in place over the western CONUS and broad cyclonic flow across much central and eastern CONUS. The only exceptions to this weak flow will be from the Great Lakes into ME, which will be along the southern periphery of the troughing across eastern Canada, and over the Pacific Northwest late in the period as a shortwave trough moves through. Surface pattern east of the Rockies will be dominated by high pressure, the center of which is forecast to gradually drift eastward from southern MO into the lower OH Valley. Dry air mass associated with this high will limit the low-level moisture across much of the central and eastern CONUS, confining the higher dewpoints to the Southeast and central/southern TX. Isolated thunderstorms are possible along and ahead of a weakening cold front from eastern NC to FL. Afternoon thunderstorms are also possible across the southern High Plains, as storms move eastward off the higher terrain, supported by a convectively augmented vorticity maximum moving within the larger scale upper ridging. Modest shear and buoyancy is expected to limit the strength of any storms that do develop. ....Interior Pacific Northwest into the Northern Rockies... Somewhat greater severe potential is expected from the interior Pacific Northwest into the northern Rockies. Here, a shortwave trough is forecast to move into the region during the afternoon, contributing to thunderstorm development as it interacts with the diurnally destabilized air mass in place. Cold mid-level temperatures will contribute to moderate buoyancy, with increasing mid-level flow resulting in moderate shear as well. These environmental conditions could result in a few stronger storms capable of damaging gusts and/or hail. ...Mosier.. 05/20/2023 $$ = = = 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) .