Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Aug 09 2025 16:59:45 ACUS02 KWNS 091659 SWODY2 SPC AC 091658 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1158 AM CDT Sat Aug 09 2025 Valid 101200Z - 111200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SUNDAY THROUGH SUNDAY NIGHT ACROSS PARTS OF THE SOUTHERN ROCKIES AND CENTRAL GREAT PLAINS INTO LOWER MISSOURI VALLEY... ....SUMMARY... Isolated to widely scattered strong thunderstorms may impact a corridor from the southern Rockies into the lower Missouri Valley Sunday through Sunday night, accompanied by a risk for potentially damaging wind gusts and some hail. ....Discussion... Models indicate that mid/upper ridging will remain generally prominent across the subtropical through mid-latitudes of the western Atlantic through eastern Pacific. Between a pair of relative centers of higher heights, offshore of the Atlantic and Pacific coasts, a notable mid-level low, initially centered near the central Canadian/U.S. border vicinity, is forecast to transition to an open wave and accelerate across northwestern Ontario through northern Quebec Sunday through Sunday night. This is likely to be trailed by a short wave trough digging east southeast of the Canadian Rockies, through the Canadian Prairies. South of the international border, weak cyclonic flow is forecast to linger between the ridging, across the Rockies through Great Plains and upper Mississippi Valley into upper Great Lakes region. One embedded short wave perturbation may gradually turn east of the Colorado Rockies through central Great Plains, perhaps preceded by one or two convectively generated or augmented perturbations across parts of the lower Missouri Valley toward Upper Midwest/Great Lakes vicinity. Near/beneath the southern periphery of this regime, it appears that the remnants of an initially broad plume of warm, elevated mixed-layer air advecting to the east of the Rockies will continue to become suppressed south/southwestward across the lower Missouri Valley and south central Great Plains. However, associated relatively dry lower/mid-tropospheric profiles with at least modestly steep lapse rates may still contribute to sizable CAPE, and an environment potentially conducive to downbursts and substantive surface cold pools in convective development. This should be maximized where seasonably high boundary-layer moisture content persists, in the wake of a stalled to slowly southward advancing convectively reinforced cold front across the central Great Plains, and either side of it across the lower Missouri Valley. ....Southern Rockies into lower Missouri Valley... Sub-synoptic developments still characterized by relatively low predictability, including potential convective evolution today into early Sunday, may considerably influence the convective potential for Sunday through Sunday night. The potentially focusing surface front and associated corridor of destabilization may be most impacted, with the environment otherwise likely to be rather marginal for organized severe thunderstorm development, in the presence of modest forcing for ascent and weak deep-layer mean flow/shear. But, the evolution of one or two thunderstorm clusters with potential to produce swaths of strong to severe gusts does not appear out of the question, particularly to the lee of the Front Range/Sangre de Cristo Mountains into the central Great Plains late Sunday into Sunday night, aided by the most notable short wave impulse and, perhaps, a nocturnally strengthening southerly low-level jet. ...Kerr.. 08/09/2025 $$ = = = 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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .