Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Oct 04 2023 19:58:47 ACUS01 KWNS 041958 SWODY1 SPC AC 041957 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Wed Oct 04 2023 Valid 042000Z - 051200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF NORTHWEST TEXAS ACROSS THE RED RIVER VALLEY AND INTO PARTS OF SOUTHERN OKLAHOMA... ....SUMMARY... Scattered to numerous severe thunderstorms are expected through early morning across parts of the southern Great Plains. Destructive, very large hail and a few significant severe wind gusts will be the main threats. Any tornado risk is expected to be brief. ....Much of western TX into southern OK... Scattered severe storms likely producing large hail have already developed across parts of the TX Panhandle and South Plains, with a few cells now moving into southwest OK. A front continues to drift southward across central OK and the TX Panhandle, with pressure falls noted within the surface trough. The greatest potential for particularly damaging hail appears to be located from northwest TX into southern OK through this afternoon and into the evening, as storms ride east/northeast along the boundary. The deepening moist layer, even with weak low-level winds, will provide favorable storm relative inflow for long-lived severe storms given moderate steering currents aloft. This, combined with additionally favorable mid to high level wind shear/elongated hodographs, suggest a storm or two could produce long swaths of significant hail. Additional severe storms producing hail will still be possible north of the boundary, as pockets of heating continue, and the air mass remains sufficiently unstable. The northeasterly boundary-layer winds north of the boundary may yield one or more left-moving cells. Other severe storms producing hail and damaging gusts are likely across much of West and western-North TX where the air mass continues to heat well ahead of the southward-moving front, including the area from Ft. Stockton/Midland northeastward toward Abilene. ...Jewell.. 10/04/2023 ..PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Oct 04 2023/ ....Southern Great Plains... Confidence continues to increase with potential for a significant severe weather episode across north/west TX and south OK this afternoon into tonight, yielding expansion of the cat 3 severe risk. The northern extent of a rather rich western Gulf air mass has spread across much of north TX and southwest to east OK, characterized by upper 60s to low 70s surface dew points. Moderate boundary-layer heating coupled with the rich moisture will yield a broad plume of 2000-3000 J/kg MLCAPE by late afternoon. Elevated thunderstorms may continue to shift east into northeast OK while renewed development across the TX Panhandle will probably intensify by early afternoon as it transitions to surface-based development along the southward-sagging composite cold front/large-scale outflow. Scattered thunderstorm development is also anticipated southward into the Trans-Pecos as low-level convergence/upslope increases near the dryline. A lack of surface cyclogenesis will result in relatively weak low-level mass response and correspondingly small low-level hodographs this afternoon in the warm sector. However, substantial speed shear above 700 mb will yield relatively straight and highly elongated mid to upper-level hodographs favoring splitting supercells with initial storm development. These initial supercells will be capable of producing very large to giant hail from 2-3.5 inches, mainly across west TX where steeper mid-level lapse rates and discrete supercell mode will persist longer. Farther north and east, consolidating outflow interactions and minimal convective inhibition will likely result in quicker upscale growth into clusters and bowing line segments by late afternoon/early evening as storm coverage becomes widespread. Still, given the favorable hodographs for strong mid-level rotation, longer-track embedded supercells will be possible, especially along the composite front/outflow across south OK initially, and over western north TX later. These may yield destructive wind-driven hail swaths with localized gusts reaching 75-85 mph. A large MCS is anticipated this evening, moving east-southeast over north/northeast TX with a decreasing severe wind risk overnight. $$ = = = 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) .