Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Mar 24 2023 16:28:35 ACUS01 KWNS 241628 SWODY1 SPC AC 241626 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Fri Mar 24 2023 Valid 241630Z - 251200Z ....THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF ARKANSAS/LOUISIANA/MISSISSIPPI AND SOUTHWEST TENNESSEE... ....SUMMARY... A severe weather outbreak is possible across the Lower Mississippi Valley and Mid-South this afternoon and tonight. The most likely time period for strong tornadoes is between 5 pm and Midnight CDT. ....Lower Mississippi Valley/Mid-South/Tennessee Valley... Upper-air analysis and more contemporary water vapor imagery features a relatively low amplitude shortwave trough centered near the New Mexico/Mexico/west Texas border vicinity, with a preceding broad belt of strong mid/high-level southwesterlies extending across the southern plains toward the Midwest. These westerlies are partially atop a convectively augmented front that extends from central/northeast Texas into the Ozarks, and then largely parallels the Lower Ohio River (but to the south). Within the warm sector, 12z upper-air analysis did feature a relative minimum of higher-caliber source-region moisture as noted in 850mb analysis (supplemented by GPS PW values) across parts of south-central/east Texas into southern Louisiana, although higher moisture content was noted across the ArkLaTex/Mid-South. Scattered thunderstorms are ongoing along the effective frontal zone from the ArkLatex into central/eastern Arkansas, and northeastward into western Tennessee and eastern Kentucky. Latest thinking is that initial development/intensification of surface-based storms should occur across northeast/east Texas, possibly far southeast Oklahoma, into western Arkansas in vicinity of the front/abating outflow and surface low vicinity. This severe threat should expand/organize east-northeastward as the surface cyclone steadily deepens and tracks northeast along the baroclinic zone through tonight. After some initial-discrete storms/supercells, it seems like that an intensifying QLCS will evolve across Arkansas and spread toward the Tennessee Valley through the evening. Strengthening low-level winds and enlarging hodographs should compensate for the northern gradient of the surface-based instability plume. This QLCS will likely contain embedded supercell and mesovortex structures supportive of tornadoes (including potential for a few EF2s) and significant damaging wind swaths (up to around 80-90 mph). Farther south, increasing low-level moisture across the Sabine Valley towards the ArkLaMiss should eventually yield a plume of moderate MLCAPE around 1500 J/kg by evening. This warm theta-e advection regime should also foster some discrete supercellular convection ahead and south/southeast of the QLCS towards late afternoon into early evening within the resultant MLCAPE gradient. Deep-layer shear profiles will support supercells, a few of which could become long-tracked across the ArkLaMiss region. Low-level hodographs, while not quite as enlarged as compared to farther north, will support a threat for strong tornadoes (EF2+) through much of the evening, until warm sector winds becomes increasingly veered from southwest to northeast overnight. ...Guyer/Moore.. 03/24/2023 $$ = = = 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) .