Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Nov 14 2022 12:47:10 ACUS01 KWNS 141247 SWODY1 SPC AC 141245 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0645 AM CST Mon Nov 14 2022 Valid 141300Z - 151200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER COASTAL AREAS OF TEXAS AND LOUISIANA... ....SUMMARY... Isolated severe weather is possible through tonight over coastal areas of Texas and Louisiana. ....Synopsis... In mid/upper levels, a progressive pattern will persist over much of the CONUS, with a broadening area of cyclonic flow from the Rockies across the Great Plains to the Mississippi Valley. This will occur as a series of shortwave troughs migrate through the southern sector of a cyclone now centered over southern MB. The associated 500-mb low will meander erratically with net southward motion toward the international (ND) border. A shortwave trough/speed max should dig southward through the western/southwestern part of the cyclonic-flow field, from its present position over AB to the northern and central Rockies. As that occurs, a separate/southern shortwave trough -- with accompanying/compact cyclone apparent in moisture-channel imagery over central NM -- should accelerate east-northeastward across west TX toward north TX and OK through 00Z, becoming an open- wave trough. By 12Z, a substantially weakened version of this perturbation should reach IL. On the 11Z surface chart, a low was drawn just inland over deep south TX -- between HRL-CRP, with marine/warm front arching northeastward over coastal waters off CRP, then east-southeastward across outer shelf waters of the northwestern/north-central Gulf. The western fringe of this boundary may briefly brush parts of the mid/upper TX Coast this afternoon, as the low migrates northeastward toward the area near or barely offshore from GLS. Tonight, the low should move eastward close to the western/central LA coastline, crossing extreme southeastern LA and tracking near HUM, before moving just offshore from the MS coastline. In the process, the warm front may move over coastal areas of south-central/southeastern LA late tonight. ....Coastal TX/LA... Scattered thunderstorms are expected to develop throughout the remainder of the day across parts of the northwestern Gulf off the mid/upper TX Coast, with some northward extension inland, before shifting eastward across coastal LA and adjacent waters. Though the main severe threat should remain over the Gulf, isolated severe hail will be possible across the outlook area. A threat for isolated strong/damaging gusts and perhaps a tornado may develop close to the immediate coast. However, the most intense convection -- including potential for discrete, surface-based and perhaps tornadic supercells -- will be greatest off the coast, over Gulf shelf waters, amid more optimal boundary-layer theta-e and minor EML/ capping influences. Over land, forecast soundings near and poleward of the low suggest a deep, moist, nearly saturated layer in low levels with some static stability very near the surface -- reinforced by the area of precip expected to form along the northern rim of the Gulf convective regime. Forecast soundings suggest MLCAPE and MUCAPE each in the 500-1000 J/kg range over the immediate mid/upper TX coast this afternoon, and perhaps over the coast of south-central/southeastern LA starting around 06Z. Effective-shear magnitudes of 50-60 kt suggests supercell potential -- both for elevated inflow inland and nearly surface-based parcels from TX coastal counties (and later some coastal LA parishes) southward across the Gulf. Large low- level hodographs will be present near the warm/marine front and northward, but characterized by decreasing accessibility of updrafts to the best-curved bottom part of those profiles with inland extent. Convective mode also may be broader/messier with northward extent across coastal areas, amid greater proximity to the mid/upper trough and related stronger large-scale ascent. As such, overland severe potential is quite conditional, but still enough to maintain a marginal unconditional severe outlook across the roughly the VCT-HOU-LCH-SIL corridor. ...Edwards/Smith.. 11/14/2022 $$ = = = 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) .