Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Sep 08 2025 05:41:06 ACUS01 KWNS 080540 SWODY1 SPC AC 080539 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CDT Mon Sep 08 2025 Valid 081200Z - 091200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ....SUMMARY... Isolated hail and damaging gusts are expected over portions of western Kansas, northwest Oklahoma and the Oklahoma/Texas Panhandles. ....Central/Southern High Plains... Mean upper ridge is forecast to hold across the Rockies through the day1 period, ensuring northwesterly flow persists across the High Plains. Early this morning, water-vapor imagery depicted a notable short-wave trough digging southeast across the central High Plains. This feature is expected to advance into southeast NE/central KS by late afternoon before advancing into MO/western AR by 09/12z. Partly in response, LLJ should increase across the High Plains from the TX Panhandle into south central NE, only veering into eastern KS late in the period. As a result, low-level warm advection will focus along a corridor from southern NE into northwest MO, ultimately inducing one or more thunderstorm clusters along the nose of the LLJ. Even so, instability may be a bit too weak to warrant much risk for severe with this activity. Of more concern will be the strongly destabilized regions of western KS into the TX Panhandle, where low-level lapse rates will steepen due to strong boundary-layer heating. Forecast soundings suggest convective temperatures will be breached around 23z, and weak low-level convergence should prove instrumental in convective initiation, as the aforementioned short wave will have advanced downstream by this time period. While large-scale forcing should be weak across this region, most HREF members develop at least isolated convection. Adequate deep-layer shear should be present for supercells and these storms will propagate south with an attendant risk for large hail, locally damaging winds, and perhaps a brief tornado or two. Greatest severe risk will be late afternoon into the late evening hours. ....Upper MS Valley Vicinity... Northern stream short-wave trough is forecast to dig southeast across southern MB/ND into the upper Red River region by early evening. This should aid LLJ that will increase across MN into the U.P. of MI by 09/06z. Large-scale forcing favors elevated convection along the nose of this jet, especially across the Arrowhead of MN/Lake Superior. Have introduced a MRGL risk along the trailing boundary across MN where steeper lapse rates may permit a few robust updrafts to evolve shortly after peak heating. Even so, this activity should be more isolated with the greatest concentration of storms expected within the more favored warm advection zone. ...Darrow/Wendt.. 09/08/2025 $$ = = = 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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .