Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Nov 05 2022 12:46:33 ACUS01 KWNS 051246 SWODY1 SPC AC 051245 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 AM CDT Sat Nov 05 2022 Valid 051300Z - 061200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Isolated to widely scattered thunderstorms are expected from parts of the Gulf Coast to the Great Lakes. Organized severe-thunderstorm potential appears minimal. ....Synopsis... In mid/upper levels, large-scale troughing will remain over western North America, as a series of strong, mainly northern-stream perturbations pivot through the associated cyclonic flow across the northeastern Pacific to northern Rockies. Farther southeast, a trough associated with the previous day's severe-weather event is apparent in moisture-channel imagery near an axis from MCI-BVO-DFW. This feature is forecast to deamplify, become more negatively tilted, and eject away from the larger-scale mean trough today. This perturbation should reach the WI/MI border and Lake Michigan by 00Z, then weaken greatly and reach James Bay by 12Z tomorrow. The associated surface low was analyzed at 11Z over southeastern IA, with attached cold front extending across eastern MO, northeastern AR, western MS, southeastern LA, to the northwestern Gulf. The northern part of the front was preceded by a band of convection across parts of IN, western/central KY, western/middle TN, and northern MS, catching up to the leading edge of the convection from southern MS southwestward. By 00Z, the low should be near MQT, with occluded/cold front arching across Lake Huron, OH, and eastern KY, decelerating or already quasistationary from northwestern AL across extreme southeastern LA and the northwestern Gulf. ....Gulf Coast to Great Lakes... A non-severe band of convection has been moving southeastward to eastward across the Delta region for a few hours, with the bulk of stronger cells and lightning activity behind the initial combined outflow/frontal line. A narrow wedge of favorably moist, surface- based effective-inflow air remains in the boundary layer ahead of this boundary, across southeastern LA and near-coastal MS. However, organized severe potential now appears too conditional and low to maintain an outlook area, given: 1. Broadly decreasing trends in lightning, reflectivity and IR cloud depth (cloud-top warming), evidencing sustained overall weakening, 2. The shallow/anafrontal character of lift along the boundary, which should keep the bulk of convection over the post-frontal boundary layer, and 3. Ejection away from the region of most-favorable mid/upper support. Farther north, a strongly forced, narrow band of near-frontal convection has been noted for the past few hours over central/ eastern MO, now moving into portions of western IL. In the wake of the cold pool from the prefrontal squall line, forecast soundings suggest that convective instability ahead of the frontal band over much of IL/IN should be elevated, rooted generally between 700-850 mb, with up to about 500 J/kg MUCAPE possible. With the bulk of the LLJ and almost all positive SRH below the LFC there, both effective SRH and shear will be modest for this relatively shallow activity. Still farther north and east across MI/OH, weaker but lower- altitude buoyancy is possible just ahead of the cold-core DCVA plume this afternoon, and a narrow/low-topped convective band (perhaps with no lightning) rooted near the surface may develop. Strong gusts directly related to convection (as opposed to gradients winds only somewhat convectively augmented) cannot be ruled out. Still, organized severe potential appears minimal, given a lack of substantial low-level instability/lapse rates. ...Edwards/Smith.. 11/05/2022 $$ = = = 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) .