Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Nov 19 2023 05:57:03 ACUS01 KWNS 190556 SWODY1 SPC AC 190555 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1155 PM CST Sat Nov 18 2023 Valid 191200Z - 201200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF CENTRAL AND NORTHEASTERN OKLAHOMA... ....SUMMARY... A couple of strong thunderstorms may develop across parts of central and northeastern Oklahoma this evening and overnight. The strongest of these storms may produce marginally severe hail. ....Synopsis... In the mid levels, a lead shortwave trough over the Rockies will move eastward over the southern Plains early this morning ahead of a second subtle wave across central NM. At the same time, a much stronger trough and 80-90 kt mid-level jet are forecast to dig southeastward over the Four Corners, while shortwave ridging intensifies over the central CONUS. The lead shortwave should merge with the approaching secondary trough, rapidly amplifying the general flow pattern over the western third of the CONUS. Strong mid-level flow spilling over the Rockies will aid in lee cyclogenesis, with a 1000-1004 mb cyclone expected to develop over parts of central OK by this evening. Intensifying surface wind fields ahead of the deepening trough will draw modest moisture northward across parts of TX and southern OK this evening. The upper trough will begin to move eastward and intensify further into a closed low over the southern Plains late tonight into early Monday. ....Central and northeastern Oklahoma... As the first in a series of shortwave troughs passes over the southern Plains early this morning, low-level warm advection is forecast to intensify ahead of the lee low and developing dryline/ surface trough. Northward advection of the modestly moist surface air mass over western/central TX and southern OK will intensify, with widespread showers and isolated embedded thunderstorms across the southern Plains likely to start the forecast period. Sustained isotropic ascent is also expected to bring widespread cloud cover limiting diurnal heating and available buoyancy for much of the day. Elevated convection should gradually expand northward across KS and the central Plains through the day as the lead shortwave and ascent lift north with it. Stronger height falls aloft, increasing differential thermal advection and the subsequent development of weak buoyancy is expected later this evening and through the overnight hours as the main shortwave trough begins to eject eastward. -20C 500 mb temps should support steepening lapse rates of 7-8 C/km sufficient for approximately 500-750 J/kg of MUCAPE over OK. Elevated atop a sizable surface inversion, isolated thunderstorms are possible over parts of central and eastern OK after 00z continuing through the overnight hours. 50-60 kt of mid-level flow and elongated hodographs may support brief organization into transient supercell structures or clusters. Isolated hail, some of which may be marginally severe, is possible over central and eastern OK immediately ahead of the cold core aloft where buoyancy is expected to be the largest. Confidence in storm coverage and organization however is very low owing to the paltry buoyancy, limited moisture depth and poor diurnal phasing of the upper-level trough. ...Lyons/Jewell.. 11/19/2023 $$ = = = 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) .