Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Jun 21 2023 05:46:18 ACUS02 KWNS 210546 SWODY2 SPC AC 210544 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1244 AM CDT Wed Jun 21 2023 Valid 221200Z - 231200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF NORTHEAST COLORADO INTO SOUTHEAST WYOMING... ....SUMMARY... Isolated severe thunderstorms are possible on Thursday across potions of the central High Plains into the Texas Panhandle and northwest Oklahoma. ....Central/Southern Plains vicinity... Upper ridging centered on the southern High Plains will continue on Thursday. Some dampening of the upper ridge is expected across parts of the central Plains into the Upper Midwest, in the wake of a midlevel shortwave impulse and convection associated with that feature the day prior (Day 1/Wed). This will result in generally weakened mid/upper flow from central NE/SD northeast into MN. South of this weakness in the upper ridge however, moderate mid/upper west/northwest flow is forecast to round the top of the ridge from CO/KS into the OK/TX Panhandles/northwest OK vicinity. This will aid in another day of severe-thunderstorm potential across the region, though storm coverage may be more sparse compared to the day before. Nevertheless, a seasonally moist airmass will be in place as far west at the I-25 corridor from northeast NM into southeast WY, and steep midlevel lapse rates will support moderate destabilization. Vertically veering wind profiles will foster effective shear magnitudes greater than 30 kt, providing support for organized convection. A broad Marginal risk (level 1 of 5) will be maintained across the region given uncertainty in storm coverage. Some of this uncertainty is being driven by how convection evolves in the Day 1/Wed time frame. Several CAMs/deterministic model forecasts suggests convection may be ongoing Thursday morning across western KS. This bowing cluster may develop southeast into western OK. While this could pose a wind/hail risk, if capping persists, it may also result in a sub-severe thunderstorm complex. Outflow from Wednesday night/Thursday morning convection also may impact severe potential by limiting heating and boundary-layer recovery. It seems most likely thunderstorms will develop near the higher terrain of the I-25 corridor in moist, upslope flow. The overall CAPE/shear parameter space will support isolated supercells capable of large hail and strong gusts. A small Slight risk (level 2 of 5) has been included where the best potential for a few severe storms is expected Thursday afternoon/early evening. If this initial activity can persist eastward into the High Plains through evening, some clustering may occur and result in a continued wind/hail risk across eastern CO into parts of western NE/KS. ....South Dakota into western MN... Scattered thunderstorms are expected in a moist and unstable environment ahead of a southeastward-advancing cold front. MLCAPE to around 1000-1500 J/kg and 20-25 kt effective shear could result in a couple of strong storms capable of producing gusty winds and small hail. The overall severe threat is expected to remain limited given weak deep-layer flow (generally less than 20 kt through 500 mb). ....Georgia in the Carolinas... Moderate southwesterly deep-layer flow is forecast through the eastern periphery of an upper trough over the Southeast on Thursday. At the surface, very moist airmass will be in place (upper 60s to low 70s F surface dewpoints). While midlevel lapse rates are expected to remain poor, heating into the low 80s F will foster MLCAPE values to around 1500-2000 J/kg. Transient organized cells in this high PW environment may pose a risk for sporadic wet microbursts and strong gusts. ...Leitman.. 06/21/2023 $$ = = = 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) .