Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Jun 23 2023 16:57:56 ACUS01 KWNS 231657 SWODY1 SPC AC 231656 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1156 AM CDT Fri Jun 23 2023 Valid 231630Z - 241200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTH-CENTRAL HIGH PLAINS... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHERN PLAINS... ....SUMMARY... Scattered severe thunderstorms, capable of producing large hail and strong/damaging wind gusts and a tornado or two, are expected across the North-central High Plains, with other severe storms across the southern Plains today and tonight. ....North-central Plains... No changes for this region aside from Marginal-related spatial adjustments across Wyoming. The most concentrated, well-organized severe threat still appears to be over parts of the High Plains from southeastern Montana to western Nebraska this afternoon and evening. Scattered thunderstorms should evolve upscale from initial multicell and supercell development near the Bighorn and Laramie Ranges, with an early multimodal threat transitioning toward severe wind (locally 65+ kt gusts possible) with time this evening and overnight. A relatively narrow corridor of favorable airmass heating, warm-advection-related recovery, and upslope flow into higher terrain will support afternoon/evening severe potential. Activity should develop over and near the Wyoming ranges this afternoon as strengthening large-scale ascent and deep-layer shear spread over the region ahead of the ejecting shortwave trough, conterminous with favorably, diabatically minimized MLCINH. Initial mixed-mode convection will offer all severe hazards, with tornadoes and significant hail being a threat from any sustained supercell(s). Steep low/middle-level lapse rates and favorable boundary-layer moisture will contribute to peak/preconvective MLCAPE ranging from near 3000 J/kg over the northeastern Colorado/southwestern Nebraska to 1000-2000 J/kg in a small part of northeastern Wyoming and southeastern Montana. Lengthening and well-curved hodographs are forecast to develop as low-level cyclogenesis proceeds, in support of the hail/tornado threat. One or two MCSs should evolve this evening, accessing theta-e advection and moisture transport related to a 40-45 kt LLJ, with aggregation of cold pools rendering an increasingly widespread threat for damaging and severe gusts. The severe risk should continue eastward across Nebraska/South Dakota much of the night. ....Southern Plains including West/North Texas and Oklahoma... A cluster of strong/severe storms is ongoing across west-central Oklahoma at late morning. These storms continue to exhibit upscale-growing trends aside from a morning history of isolated severe-caliber wind gusts. The potential for wind damage and isolated hail may persist east-southeastward across southern/central Oklahoma and nearby north Texas this afternoon. Otherwise, farther west, widely scattered thunderstorms are expected to redevelop by mid/late afternoon near the dryline/lee trough across far west/northwest Texas including the Texas South Plains. These initially high-based storms will progress eastward, with some of these storms potentially interacting with the outflow-reinforced baroclinic zone via the early day storms. Storms will gradually encounter greater low-level moisture as they move eastward, with surface dewpoints into the 60s and lower 70s F, with 2500-3500 J/kg MLCAPE near and east of the Caprock. Though near-surface flow will be modest, strong veering with height will enable enough deep-layer shear (effective values around 35-40 kt) for a blend of early multicell and supercell modes, offering both large hail and severe-caliber wind gusts. A gradual coalescence of cold pools from multiple storms is probable, with a severe risk probably continuing eastward this evening into the overnight across north Texas and possibly southern Oklahoma. ....Eastern Colorado/western Kansas... Severe risk adjustments have been made across the region given trends in short-term observations/guidance. Concern exists for a viable potential for intense storm development, even if somewhat isolated, by mid/late afternoon, within a supercell-favorable environment including steep lapse rates, strong buoyancy and 40+ kt effective shear. ....Mid-Atlantic States/Delmarva... Ahead of the upper low centered over Ohio/Lower Great Lakes, a moist environment with moderately enhanced low-level southerly winds may support a few stronger/locally severe storms this afternoon across the region. ...Guyer/Gleason.. 06/23/2023 $$ = = = 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) .