Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri May 19 2023 16:25:45 ACUS01 KWNS 191625 SWODY1 SPC AC 191623 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CDT Fri May 19 2023 Valid 191630Z - 201200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE SOUTHERN GREAT PLAINS INTO SOUTHWEST AR... ....SUMMARY... Scattered severe thunderstorms are possible across parts of the southern Great Plains to southwest Arkansas, centered on 3 to 11 PM CDT. Large hail should be the main threat in terms of coverage, with damaging winds also possible. ....Southern Great Plains to AR... A surface cold front will continue to plunge down the Great Plains as ridging builds south through tonight. This boundary, along with a corridor of pre-frontal confluence ahead of it, and a post-frontal upslope regime behind it, will be the focus for scattered thunderstorm development during the mid to late afternoon. A decayed MCS along the OK/AR and its poor mid-level lapse rates/remnant cloud debris will serve as the northern/eastern limiter to the organized severe threat in AR later today. An MCV trailing to its west in central OK should aid in thunderstorm redevelopment across southeast OK to the Ark-La-Tex later this afternoon. This region will lie in the northeast gradient of surface-based instability with weakness in the wind profile above 500 mb. Nevertheless, modest low-level hodograph curvature should foster a few supercells that consolidate into a cluster across at least southwest AR before weakening. More favorable upper-level winds will exist farther southwest into central TX owing to a southern-stream sub-tropical jet downstream of a quasi-stationary low near the northern Gulf of CA. This combined with a corridor of large buoyancy (MLCAPE of 2500-3000 J/kg) and potential for pre-frontal development should favor a few supercells capable of producing significant severe hail. This threat may remain relatively confined owing to greater MLCIN and lack of ascent with southern extent, and eventual undercutting of the cold front. Storm-scale clustering should support a brief uptick in severe wind gust potential, but a broader MCS/greater wind coverage threat appears unlikely given weak to somewhat difluent low-level flow this evening. Finally, a corridor of post-frontal discrete supercell development is likely across the northern portion of the Permian Basin as convection develops off the higher terrain of southeast NM. Large hail will be the main threat here as well with the overall spatial extent limited by the undercutting nature of the cold front and diminishing of buoyancy from north to south behind it. ....Central OR... Modest low to mid-level moisture will persist in a south-southwesterly flow regime across OR/WA. Forcing for ascent appears to be nebulous, so terrain circulations will be the primary driver of thunderstorm development later this afternoon off the higher terrain of south-central OR. Vertical shear will be rather weak, but a couple multicell clusters could produce isolated, marginal severe gusts and small to marginally severe hail in the late afternoon to early evening. ...Grams/Lyons.. 05/19/2023 $$ = = = 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) .