Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Aug 18 2023 04:43:47 ACUS02 KWNS 180443 SWODY2 SPC AC 180442 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1142 PM CDT Thu Aug 17 2023 Valid 191200Z - 201200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... The risk for severe thunderstorms appears negligible across the U.S., Saturday through Saturday night. ....Discussion... A mid-level low, initially centered over portions of northern New England and the adjacent St. Lawrence Valley, is forecast to remain progressive during this period, as consolidating upstream mid-level troughing within the westerlies accelerates into and across the Hudson/James Bay vicinity. Much of the remainder of the U.S., to the east of the Rockies, will remain under the influence of expanding mid-level ridging, which may become centered over the central Great Plains/lower Missouri Valley vicinity. Farther west, models indicate that weak mid-level troughing will prevail along much of the U.S. Pacific coast through the Baja Peninsula. Within southerly deep-layer mean flow to the east of this trough axis, Hurricane Hilary may gradually accelerate northward into the Pacific waters near/west of Baja California Sur. Strongest potential instability Saturday may become focused in a corridor along and ahead of a southward advancing cold front associated with the Canadian short wave, across parts of the upper Mississippi Valley into portions of the mid Missouri Valley and eastern portions of the central Great Plains. This likely will be aided by strong heating of a seasonably moist boundary layer, beneath a very warm elevated mixed layer. But, it appears that forcing for ascent beneath the mid-level ridge will be too weak to overcome the mid-level inhibition and support sustained thunderstorm development. Monsoonal moisture may support considerable thunderstorm development Saturday across the West, from the Sierra Nevada, northern California coastal ranges, and portions of the southern Cascades into the northern Rockies. Further strengthening of southerly mid-level flow and lower/mid-tropospheric moistening is forecast downstream of Hilary, across much of the Southwest, centered on the lower Colorado Valley. While thunderstorm activity developing within this regime could pose some risk for rather localized downbursts, the increasingly saturated low-level profiles seem likely to minimize the overall risk for severe surface gusts during this period. ...Kerr.. 08/18/2023 $$ = = = 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) .