Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Sep 18 2023 04:51:54 ACUS01 KWNS 180451 SWODY1 SPC AC 180450 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1150 PM CDT Sun Sep 17 2023 Valid 181200Z - 191200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON AND EVENING ACROSS PARTS OF THE TEXAS AND OKLAHOMA PANHANDLES AND ADJACENT PORTIONS OF SOUTHWESTERN KANSAS... ....SUMMARY... Isolated to widely scattered strong thunderstorms may impact parts of the Texas and Oklahoma Panhandle vicinity, and adjacent portions of southwestern Kansas, late this afternoon and evening. These may become capable of producing small hail and locally severe wind gusts. ....Synopsis... Within larger-scale eastern U.S. mid/upper troughing, one significant short wave impulse is forecast to accelerate north-northeastward near the Atlantic coast, after crossing the southern Appalachians by mid morning. As it does, models indicate that associated forcing for ascent will contribute to more substantive cyclogenesis offshore of the Mid Atlantic coast through New England coastal areas later today through tonight. A trailing cold front likely will advance offshore of the southern Mid Atlantic coast, into the central Florida Peninsula, and through much of the northeastern Gulf of Mexico, before stalling beneath generally weak cyclonic mid-level flow. An evolving plume of seasonably high moisture content along/ahead of the front will support scattered thunderstorm development, including across coastal and interior southern Florida, aided by colliding Atlantic and Gulf coastal sea-breezes. Upstream, generally modest to weak zonal mid-level flow will prevail inland of the Pacific coast through much of the Great Plains. Beneath this regime, and sufficiently cool mid-levels to support weak CAPE, scattered diurnal thunderstorm development appears probable across the northern Sierra Nevada and Great Basin, into the Rockies. To the lee of the Rockies, at least some moistening is likely on southerly low-level return flow to the east of deepening surface troughing. It appears that this will contribute to sufficient destabilization to support widely scattered thunderstorm development, aided by daytime heating across parts of the Texas and Oklahoma Panhandle vicinity, and lower/mid-tropospheric warm advection later tonight across portions of the Corn Belt. ....Texas/Oklahoma Panhandles and southwestern Kansas... Mid/upper support for convective development, prior to the approach of a subtle perturbation forecast to progress across the Colorado Rockies this evening, appears weak. Weak mid-level warming may also tend to increase inhibition late this afternoon. However, it is possible that low-level convergence within the lee surface trough, coupled with the approach of convective temperatures with daytime heating, may be sufficient to support isolated to widely scattered thunderstorm development. Although deep-layer shear likely will remain modest at best, with CAPE for a well mixed boundary layer exceeding 1000 J/kg beneath modestly steep mid-level lapse rates, stronger storms may pose a risk for small hail and locally strong downbursts. Some consolidation and upscale convective growth, with potential for a bit more widespread strong surface gusts, might not be out of the question this evening, with modest nocturnal low-level jet strengthening across the eastern Texas Panhandle into western Kansas. ...Kerr/Bentley.. 09/18/2023 $$ = = = 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) .