Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jun 24 2023 16:32:08 ACUS01 KWNS 241632 SWODY1 SPC AC 241630 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sat Jun 24 2023 Valid 241630Z - 251200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE UPPER MIDWEST TO THE MID-MS VALLEY... ....SUMMARY... Scattered severe thunderstorms are most likely across portions of Minnesota and Iowa into the Mid-Mississippi Valley through this evening. Brief tornadoes, large hail, and damaging winds will be possible. ....Upper Midwest to Mid-MS Valley... Remnants of a decaying MCS persist in eastern IA with residual cloud cover and convective redevelopment in its wake across central into southwest IA. More pronounced insolation has occurred over northwest IA and parts of eastern NE. This will likely yield a moderately unstable air mass with MLCAPE approaching 2500 J/kg in a few hours. Morning guidance is insistent on surface-based thunderstorm development occurring by early afternoon, which appears a bit too soon given the lingering morning convection/cloudiness, but is plausible owing to modest mid-level lapse rates/EML. As such, confidence is below-average with regard to timing and evolution of this afternoon's severe threat. Downstream of a 60-65 kt 500-mb westerly jetlet centered on NE, deep-layer shear will support potential for several supercells. A few-hour window for a couple of these to produce tornadoes may overlap along the residual outflow boundary before convection likely consolidates into clusters and low-level winds become more veered into the evening. East to southeast-moving clusters may develop into a semi-organized MCS during the evening and yield a strong to isolated severe wind threat across the Mid-MS Valley. This activity should gradually weaken tonight after eventually outpacing greater instability/buoyancy to its west. A separate area of lower-topped tornado potential is evident in northwest/north-central MN along the surface warm front that will extend east of the primary cyclone centered near the northeast SD/southeast ND border area. Backed surface winds that veer with height will support enlarged low-level hodograph curvature. In conjunction with low LCLs, these factors may support a threat for brief tornadoes during the late afternoon to early evening. ....West TX to the Ozark Plateau... Isolated to scattered high-based thunderstorms will develop during the late afternoon to early evening across at least west TX, and perhaps across parts of OK this evening into tonight. With a stout mid-level anticyclone centered along the Trans-Pecos portion of the Rio Grande, deep-layer shear will be progressively stronger with northeast extent towards the Ozark Plateau. Sporadic severe gusts from microbursts will be the main threat in TX, with a conditional threat for isolated severe wind/hail into the Ozark Plateau. ....LA vicinity... Despite weak low-level shear, a belt of modest mid-level northerlies will support potential for an isolated severe wind and hail threat as isolated to scattered thunderstorms develop this afternoon within the boundary-layer moisture/buoyancy gradient between LA/MS. ...Grams/Wendt.. 06/24/2023 $$ = = = 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) .