Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jan 23 2023 05:53:26 ACUS02 KWNS 230553 SWODY2 SPC AC 230552 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1152 PM CST Sun Jan 22 2023 Valid 241200Z - 251200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS TUESDAY EVENING INTO TUESDAY NIGHT ACROSS SOUTHEASTERN LOUISIANA AND MISSISSIPPI...SOUTHWESTERN ALABAMA AND THE WESTERN FLORIDA PANHANDLE... ....SUMMARY... Severe thunderstorms are possible near mid to upper Texas coastal areas Tuesday afternoon, before spreading into parts of southeastern Louisiana and Mississippi through southwestern Alabama and the western Florida Panhandle Tuesday night. These storms will be accompanied by a risk for potentially damaging wind gusts and tornadoes, a few of which could be strong. ....Synopsis... An initially prominent mid-level high over the southern mid-latitude Pacific likely will weaken, with a new high center gradually beginning to form in higher latitudes, within persistent larger-scale ridging. This ridging is forecast to continue to build north-northeastward across British Columbia, Yukon and parts of the Northwest Territories Tuesday through Tuesday night, with amplified large-scale troughing being maintained downstream, along and east of the Rockies Mountains. The most prominent perturbation within this regime, initially a vigorous short wave trough with a compact, embedded deep mid-level low, is still forecast to accelerate out of the base of the troughing by early Tuesday. The NCEP SREF remains notably slower than most other model output, which generally indicates that the perturbation will rapidly progress across the southern Great Plains into the Mid South by late Tuesday night, accompanied by significant surface cyclogenesis near mid/upper Texas coastal areas into the lower Mississippi Valley, then north-northeastward into the Mid South. As this occurs, an intense west-southwesterly mid/upper jet (including 90-100 kt around 500 mb) is forecast to develop across the lower Mississippi through Tennessee Valleys by 12Z Wednesday. In association with the developing cyclone, a southerly low-level jet may include speeds increasing to 50-70 kt, and perhaps even stronger to the east of the lower Mississippi Valley during a period of more rapid deepening Tuesday evening. ....Southeast Texas coastal through central Gulf Coast states... With little appreciable change to model forecasts concerning the synoptic forcing, the presence of an initially cool/stable boundary layer across much of the Gulf Coast region remains the primary potential limiting factor to the development of a more substantive risk for severe thunderstorms Tuesday through Tuesday night. The boundary layer across much of the northern Gulf of Mexico will also still be in the process of modifying from prior frontal intrusions, but it does appear that mid/upper 60s F surface dew points will rapidly advect toward northwestern through north central Gulf coastal areas, and perhaps at least a bit inland. Near-surface destabilization across and inland of mid into upper Texas coastal areas will contribute to an environment conducive to organizing convective development, including supercells Tuesday afternoon. Thereafter, similar destabilization in a corridor across southeastern Louisiana into southwestern Alabama still seems probable Tuesday evening through Tuesday night. Beneath a plume of modestly steepening lapse rates, this is expected to contribute to a corridor of destabilization sufficient to maintain an organized convective cluster or line, with embedded supercells, along an eastward advancing pre-cold frontal confluence zone. Aided by low-level warm advection in advance of this activity, this may be preceded by a few discrete supercells. It is still possible that a residual layer of moist adiabatic to more stable near-surface lapse rates within the warm sector could tend to minimize the number of potentially severe storms. However, the latest (23/03Z) forecast soundings from the Rapid Refresh, which extend out through 06Z Tuesday night, increase confidence for at least weak surface-based destabilization to occur in a corridor across southeastern Louisiana into southwestern Alabama/western Florida Panhandle. With low-level hodographs forecast to become very large and clockwise curved, in the presence of strong deep-layer shear, the environment may become supportive of a couple strong tornadoes in the supercell storms. ...Kerr.. 01/23/2023 $$ = = = 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) .