Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Nov 18 2023 08:25:00 ACUS03 KWNS 180824 SWODY3 SPC AC 180823 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 AM CST Sat Nov 18 2023 Valid 201200Z - 211200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EAST TEXAS INTO PARTS OF THE LOWER MISSISSIPPI VALLEY AND SOUTHEAST... ....SUMMARY... Severe thunderstorms will be possible Monday afternoon into Monday night from east Texas into parts of the lower Mississippi Valley and Southeast. Damaging wind and a few tornadoes are expected to be the primary hazards, though isolated hail will also be possible. ....Synopsis... A complex mid/upper-level trough is forecast to gradually shift eastward across the central CONUS on Monday. A vigorous shortwave is expected to move through the base of the trough, potentially resulting in consolidation of a mid/upper-level cyclone from eastern portions of the central Plains toward the mid-MS Valley. As this occurs, a surface cyclone initially over the southern Plains is forecast to move eastward toward the lower MS Valley. A trailing cold front will move from east TX toward the ArkLaMiss region by early Tuesday morning. ....East TX into the lower MS Valley and Southeast... Increasingly rich low-level moisture (with dewpoints into the mid/upper 60s F) is expected to advance northward during the day on Monday from east TX into the lower MS Valley, in advance of the surface low and cold front. Modest heating will support moderate buoyancy along/east of the front across east TX, where storm development is possible by late afternoon. Strengthening deep-layer shear will support supercell potential, though there may be a tendency toward more of a cluster or linear mode as storm coverage increases along/ahead of the front into the evening. Initial storm development from east TX toward the ArkLaTex will pose a threat of large hail and locally damaging gusts. With time, the hail threat may tend to decrease, but the tornado threat will increase with any persistent supercells and/or line-embedded mesovortices as low-level shear/SRH strengthens during the evening. Instability will tend to weaken with eastward extent, but any organized storm structures may continue to pose a threat of locally damaging wind and a tornado or two into the overnight, as they move through a moist and strongly sheared environment. While guidance has come into somewhat better agreement regarding the scenario described above, important differences remain with respect to the amplitude and intensity of the basal shortwave trough and attendant surface cyclone. The stronger solutions would support greater low-level mass response, and a greater tornado/wind threat compared to the weaker and less amplified solutions. A rather broad Slight Risk has been maintained with this outlook, in order to account for various plausible scenarios regarding the magnitude and favored corridor of the primary severe risk. ...Dean.. 11/18/2023 $$ = = = 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) .