Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Nov 13 2024 10:01:20 ACUS48 KWNS 131001 SWOD48 SPC AC 130959 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Wed Nov 13 2024 Valid 161200Z - 211200Z ....DISCUSSION... Some severe potential remains evident across parts of the southern/central Plains (and potentially farther east) early next week, though uncertainty remains regarding the most favored corridor and the magnitude and sufficiency of low-level moisture/instability. ....D5/Sunday - D6/Monday... On Saturday, a shortwave trough and attendant surface low are forecast to move across the northern Great Plains. Low-level southeasterly flow will result in early-stage moisture return into the southern/central Plains, as a surface ridge shifts eastward across the eastern CONUS. Meanwhile, a shortwave mid/upper-level trough initially near the southern CA/Baja coast may evolve into a closed upper-level low as it digs east-southeastward from late Saturday into early Sunday. This trough/low is then forecast to eject northeastward as a negatively tilted trough across parts of the southern/central Plains from late Sunday into Monday, accompanied by significant surface cyclogenesis. The primary uncertainty regarding severe potential for D5/Sunday into D6/Monday is the magnitude of low-level moisture return and destabilization across the warm sector of the developing surface low. While low/mid 60s F dewpoints may return into parts of TX and perhaps OK, with 50s F dewpoints farther north, limited heating and relatively weak lapse rates will limit buoyancy, with the GFS/ECMWF and their related ensembles suggesting MLCAPE of 500 J/kg or greater may be confined to parts of central/south TX, with increasingly limited buoyancy farther north. Some severe potential could evolve on D5/Sunday, especially later in the period when the ejecting shortwave trough may begin to impinge on richer moisture from southwest into central TX. An intensifying low-level jet may support development of widespread convection from late on D5/Sunday into D6/Monday, with a strongly forced band of convection potentially moving east-northeastward across a larger portion of the southern/central Plains. Despite the very limited instability that is currently anticipated across much of the region, the intense wind fields and strong ascent associated with the ejecting shortwave trough (as depicted by the GFS/ECMWF and some ensemble members) could support an organized severe threat within a low-CAPE/high-shear regime. Uncertainty remains regarding the most favorable corridor, with the GFS/ECMWF favoring parts of the southern/central Plains, while some ensemble members favor a zone farther east from the ArkLaTex into the mid MS Valley. ....D7/Tuesday - D8/Wednesday... Some severe potential could continue into D7/Tuesday into parts of the Midwest and Ohio Valley, though there may be a tendency for stronger deep-layer flow and ascent to become increasingly displaced from sufficient moisture and instability. NHC is currently forecasting a high probability of tropical cyclone formation late this week into the weekend across the central/western Caribbean Sea. Predictability remains very low regarding the possibility for this system to influence severe potential across the Southeast toward the middle of next week. ...Dean.. 11/13/2024 = = = 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) .