Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Apr 21 2025 05:55:38 ACUS02 KWNS 210555 SWODY2 SPC AC 210554 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Mon Apr 21 2025 Valid 221200Z - 231200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHERN HIGH PLAINS INTO PARTS OF SOUTHERN KANSAS... ....SUMMARY... Isolated severe thunderstorms are possible on Tuesday across portions of the southern Plains. ....Synopsis... Low-amplitude west/southwest mid/upper flow will prevail across the south-central and southeast states on Tuesday. A belt of stronger westerlies aloft will reside across the northern tier of the U.S. as a series of upper troughs migrate eastward from the northern Plains to the Northeast. At the surface, low pressure over Quebec and an associated cold front will be located from the Hudson Valley into the NC/VA Piedmont. Further west, low-level moist advection on south/southeasterly low level flow will allow modified Gulf moisture to spread northward from the Lower MS Valley into the southern High Plains. ....Southern Plains to southern KS... Modest Gulf moisture will spread north and west through the day to near the NM/TX border and across much of OK into southern KS. Forecast guidance suggest a weak shortwave impulse will eject across the southern Rockies in modest west/southwesterly flow aloft. While height tendencies will remain neutral, precluding much in the way of surface cyclogenesis, a sharpening dryline is forecast to extend from southwest KS into the OK/TX Panhandles, then southward near the NM/TX border. Low-level moist advection beneath steep midlevel lapse rates will support moderate destabilization (MLCAPE 1500-2500 J/kg). While deep-layer flow will remain modest, vertically veering wind profiles will contribute to supercell wind profiles, with elongated/straight hodographs. Isolated supercells will pose a risk for large hail. Furthermore, strong heating will result in steep low-level lapse rates and a well mixed boundary layer, supporting isolated strong to severe outflow gusts. As a southerly low-level jet increases during the evening, some potential will exist for convection to develop into an eastward developing MCS. If this occurs, some severe potential could persist eastward away from the dryline into portions of western north Texas and western OK. ....IA/WI/IL... A stalled frontal boundary will extent across the Mid-MO Valley into southern WI. Modest moisture return and persistent isentropic ascent along this boundary may be sufficient for isolated thunderstorm development amid weak diurnal destabilization. Low to midlevel flow will remain rather weak, but rapidly increase above 700 mb, supporting effective shear magnitudes greater than 40 kt. Cold temperatures aloft (-17 C near 500 mb) will support MLCAPE to around 500 J/kg, and isolated convection could produce sporadic hail. ....Carolinas... A cold front associated with a surface low over Quebec will develop southeast across the Mid-Atlantic and Carolinas during the afternoon/evening. Strong heating of a modestly moist boundary layer ahead of the front will support a corridor of MLCAPE up to 1000-1500 J/kg. Weak low-level southwesterly flow will increase with height, support effective shear magnitudes up to 35 kt. This should be sufficient for a few stronger/organized cells. Steep low-level lapse rates and somewhat elongated hodographs suggest transient supercells capable of strong gusts and isolated hail will be possible. ...Leitman.. 04/21/2025 $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .