Subj : DAY48SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Nov 26 2022 09:06:43 ACUS48 KWNS 260906 SWOD48 SPC AC 260905 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0305 AM CST Sat Nov 26 2022 Valid 291200Z - 041200Z ....DISCUSSION... ....D4/Tuesday: Eastern TX into the ArkLaMiss region... Severe-thunderstorm potential remains evident on D4/Tuesday from eastern TX into the ArkLaMiss region, as low-level moisture, midlevel lapse rates, and deep-layer wind shear all strengthen in advance of a deep mid/upper-level trough and attendant surface cyclone moving eastward across the Great Plains and Midwest. Model spread remains regarding the timing of the mid/upper-level trough, surface cyclone, and cold front. The GFS and GEFS continue to be somewhat slower, while the ECMWF and EC ensembles and UKMET/Canadian guidance are generally somewhat faster. Despite these differences, most guidance depicts increasing thunderstorm coverage Tuesday afternoon and especially Tuesday evening within an environment favorable for organized convection. Aside from system timing, the primary uncertainty is the extent of diurnal heating across the warm sector, given the potential for widespread cloudiness and antecedent precipitation. However, with rich low-level moisture expected to stream northward in advance of the cold front, even modest heating will support a threat of surface-based supercells and organized clusters/lines, with an attendant threat of all severe hazards. The highest severe probabilities for D4/Tuesday have been maintained across the ArkLaMiss region, where the most favorable overlap of instability, low-level and deep-layer shear, and storm coverage is currently expected. Some adjustments remain likely as the event approaches, depending on model trends regarding the timing of the mid/upper-level trough and cold front. ....D5/Wednesday: Southeast into the Ohio Valley... While some severe-thunderstorm potential may spread eastward on D5/Wednesday into parts of the Southeast and/or TN/OH Valleys, increasing model spread and the influence of widespread upstream convection on D4/Tuesday cast considerable uncertainty on the location and magnitude of the threat. Wind profiles will remain favorable for organized convection in advance of the eastward-moving cold front, though large-scale ascent may tend to become increasingly removed from the more favorable moisture/instability. Confidence in any lingering organized severe-thunderstorm threat is too low to include a 15% area at this time. ....D6/Thursday - D8/Saturday... Model spread continues to increase into next weekend, though there is generally good agreement regarding a substantial frontal passage across the eastern CONUS into the Gulf of Mexico, resulting in limited destabilization potential and generally low severe-thunderstorm potential from Thursday through Saturday of next week. ...Dean.. 11/26/2022 = = = 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) .