Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Dec 16 2024 16:30:25 ACUS01 KWNS 161630 SWODY1 SPC AC 161628 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1028 AM CST Mon Dec 16 2024 Valid 161630Z - 171200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHEAST TEXAS INTO ARKANSAS AND WESTERN TENNESSEE... ....SUMMARY... Isolated strong to severe thunderstorms with mainly a damaging wind threat may occur today across parts of the ArkLaTex into western Tennessee and vicinity. Some hail may also occur. ....Synopsis... The upper trough over the northern Plains and Upper Midwest will move across the Great Lakes today. Related surface cyclone will develop eastward over northern Ontario, with a trailing cold front advancing east-southeastward across parts of the OH Valley, Mid-South, and southern Plains. The western portion of this front will stall and weaken across the ArkLaTex into central TX by this evening. ....ArkLaTex into the Mid-South... Scattered to numerous showers and thunderstorms are ongoing this morning across parts of northern AR into the lower OH Valley, generally along/near the front. Current expectations are for the better forcing associated with the upper trough to remain mostly displaced to the north of the warm sector through the day, with limited low-level convergence along the cold front and modest low-level warm advection persisting. Latest visible satellite imagery also shows low cloud cover remaining prevalent across much of the ArkLaTex and Mid-South/lower MS Valley. These clouds will likely hinder daytime heating to some extent. Modest mid-level lapse rates were also noted on the 12Z soundings at SHV/LZK, with somewhat better lapse rates aloft at FWD. Even with these limitations regarding forcing and instability, most guidance continues to show around 500-1000 J/kg of MLCAPE along/ahead of the cold front from northeast TX into AR and western TN by mid afternoon. A gradual uptick in convective coverage and intensity should occur through the afternoon across these areas, with modest but sufficient deep-layer shear (25-35 kt) for some updraft organization. Most 12Z HREF guidance shows small clusters developing and spreading east-southeastward through the early evening. Even though low-level lapse rates will probably remain poor due to the limited daytime heating, there still appears to be enough of a signal to support inclusion of a Marginal Risk, mainly for isolated damaging winds. Some hail may also occur across northeast TX into AR, where greater instability should be present. ...Gleason/Squitieri.. 12/16/2024 $$ = = = 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) .