Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu May 11 2023 12:45:51 ACUS01 KWNS 111245 SWODY1 SPC AC 111244 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0744 AM CDT Thu May 11 2023 Valid 111300Z - 121200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS PARTS OF OK AND KS... ....SUMMARY... Scattered severe thunderstorms are expected this afternoon and evening across parts of the Great Plains centered on Kansas and Oklahoma. The greatest threat for at least a couple strong tornadic supercells should exist across central Oklahoma between 5 to 9 PM CDT. ....Central to southern Great Plains... A pronounced mid-level low over the Raton Mesa will gradually weaken as it drifts into the central High Plains through tonight. This weakening trend will result in a moderate LLJ response this evening into tonight with pockets of 30-45 kt 850-mb winds. Attendant surface cyclone will still diurnally deepen as it similarly drifts from the Raton Mesa into southwest KS today. The dryline will mix into western OK and arc south-southwest into the Edwards Plateau. A north/south-oriented inverted trough/quasi-stationary front will extend north to the western Dakotas. Dual corridors of thunderstorms are ongoing across a part of southeast CO immediately north of the low and lingering farther southeast near the northwest TX/southwest OK border. This latter area is expected to diminish through midday, resulting in the focused ascent region over southeast CO to spread east into western KS. Low-topped supercells will become increasingly probable midday to early afternoon within a marginally buoyant environment initially. A smaller area of supercell development may also form in the wake of this activity near the CO/KS border later in the afternoon and yield a persistent severe threat into early evening. A more volatile supercell environment should develop ahead of the dryline in the western to central OK vicinity. A pronounced gradient in MLCAPE is likely by late afternoon to early evening as the most robust boundary-layer heating post-dryline occurs in TX, while a plume of richer moisture advects north ahead of it. This should support MLCAPE approaching 1500 J/kg near the OK/KS border to around 3500 J/kg along the Red River. While a 500-mb jetlet over the southern High Plains will be in an overall weakening state, its favorably timed eastward translation across the dryline should support sustained supercells. Upper-level wind fields will weaken with height and the bulk of hodograph structure will consist of enlarged curvature from 0-3 km. This suggests supercells should tend towards an HP character with a slow-moving cluster type evolution, especially with southern extent into north TX. Guidance has a bit more consistency with a moderate increase in low-level flow this evening, supporting a strong tornado threat with the most intense supercells over central OK. A small MCS/embedded supercell cluster will probably persist into eastern OK before eventually weakening overnight. ....Lower MS Valley vicinity... A low-amplitude convectively induced shortwave impulse over the Ark-La-Tex will gradually shift east towards the TN Valley through tonight. With stronger boundary-layer heating expected towards the central Gulf Coast, increasingly broad convective development is anticipated into the afternoon ahead of this impulse. Weak deep-layer shear will likely prevail across much of the region. Still, some multicell clustering will offer a threat for sporadic damaging wind gusts along with marginally severe hail into early evening. ...Grams/Kerr.. 05/11/2023 $$ = = = 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) .