Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jun 10 2023 05:00:11 ACUS02 KWNS 100500 SWODY2 SPC AC 100458 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1158 PM CDT Fri Jun 09 2023 Valid 111200Z - 121200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SUNDAY AFTERNOON AND EVENING PARTS OF SOUTHERN MISSOURI AND ILLINOIS...WESTERN KENTUCKY...WESTERN AND MIDDLE TENNESSEE...NORTHERN MISSISSIPPI AND ALABAMA...AND MUCH OF ARKANSAS... ....SUMMARY... An organized cluster of thunderstorms may evolve across parts of the Ozark Plateau and lower Ohio Valley into Mid South vicinity Sunday afternoon and evening. Initial storms may pose a risk for severe hail, before damaging wind gusts become the more prominent potential severe hazard. ....Synopsis... Mean westerly flow across much of southern Canada and the U.S. appears likely to remain weak through this period, with a series of embedded, slow moving lower/mid-tropospheric cyclones in various states of evolution. At mid-levels, the most prominent circulation associated with a deep occluding surface cyclone may remain quasi-stationary over the northwestern Atlantic, to the east the Canadian Maritimes. In the wake of a trailing cold front, much of the Mid Atlantic and Northeast will be slow to destabilize. Upstream, the center of another significant mid-level low (evolving to the east-southeast of a lingering mid-level high centered over southern Saskatchewan) is forecast to slowly redevelop south-southwestward across the upper Great Lakes region, in response to short waves pivoting around its periphery. It appears that one convectively generated or enhanced perturbation may dig across the lower Missouri into Tennessee Valleys Sunday through Sunday night, along the southern periphery of the broader cyclonic flow. This may at least temporarily suppress the northeastward progression of building mid-level ridging across the southern Great Plains, in advance of a weakening mid-level low slowly redeveloping inland of the southern California coast into the southern Great Basin by early Monday. It does appear that the latter development will be accompanied by a belt of strengthening southwesterly mid/upper flow across northern Baja into the southern Rockies. ....Southern Great Plains into Ohio Valley... Models continue to indicate that the Great Lakes low will be accompanied by modest surface cyclogenesis across the Ohio Valley into lower Great Lakes region during this period, with a reinforcing intrusion of seasonably mild/dry air forecast to reach the upper Ohio Valley into Mid South and southern Great Plains Red River Valley by 12Z Monday. This likely will be preceded by an influx of seasonably moist boundary-layer air from the southern Great Plains into lower Ohio Valley, which may contribute to sizable mixed-layer CAPE ranging from 1500-3000+ J/kg. The environment with the larger CAPE in the presence of steeper lapse rates across the Red River Valley vicinity may remain capped beneath the mid-level ridging, and there are lingering uncertainties concerning possible impacts of outflow from prior convective development. However, the latest NAM and Rapid Refresh suggest that a remnant MCV embedded within the cyclonic mid-level flow may provide a focus for intensifying thunderstorm development across parts of east central/southeastern Missouri into the lower Ohio Valley by late Sunday afternoon. Additional storms may develop within an axis of stronger heating and destabilization trailing back across the Ozark Plateau, before gradually growing upscale and organizing in the presence of favorably sheared 30-50 kt westerly/northwesterly flow in the 850-500 mb layer. A few embedded supercell structures appear possible, accompanied by a risk for severe hail and perhaps a tornado or two, before potentially damaging wind gusts become the more prominent hazard into mid to late evening, while convection propagates southeastward. ....Colorado Front Range into Sangre de Cristo Mountains... Beneath strengthening difluent southwesterly mid/upper flow, models suggest that moistening east to southeasterly low-level flow may contribute to sufficient instability and shear to support scattered strong thunderstorm development near the higher terrain late Sunday afternoon and evening. This may include a few supercell structures posing at least some risk for severe hail and wind. ...Kerr.. 06/10/2023 $$ = = = 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) .