Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Aug 07 2023 16:42:22 ACUS01 KWNS 071642 SWODY1 SPC AC 071640 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Mon Aug 07 2023 Valid 071630Z - 081200Z ....THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS FAR EASTERN KY/NORTHEAST TN/NORTHWEST NC...WESTERN AND NORTHERN VA...SOUTHERN AND EASTERN WV...CENTRAL MD...AND SOUTH-CENTRAL PA... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL AND SOUTHERN HIGH PLAINS... ....SUMMARY... A severe weather outbreak is expected across parts of the eastern U.S. today with widespread and locally destructive damaging winds and tornadoes as the greatest threats, especially across the southern/central Appalachians and Mid-Atlantic States. ....Southeast to the Upper Ohio Valley to the Mid-Atlantic States... Owing to a very moist/unstable air mass and very strong winds aloft for August, a widespread severe-weather risk is already unfolding at late morning/midday across a broad region, initially west of the Appalachians spine. Refer to ongoing Watches and Mesoscale Discussions for the latest regional details. A shortwave trough over the Lower Ohio Valley will continue to advance toward the northern Appalachians by evening. A pair of 500-mb speed maxima from 55-65 kts are expected to be centered by late afternoon across eastern KY/TN and southern WV into western VA/NC, and separately over the Mid-South. Peak flow within an expansive 700-mb jet should be centered between the 500-mb maxima across the TN Valley. A plume of large potential buoyancy supported by high PW and steep mid-level lapse rates, and centered over the Mid-South/TN Valley will expand east-northeast towards the central/southern Appalachians with an expansive swath of MLCAPE from 2000-3500 J/kg expected by peak heating. Ongoing storms across eastern portions of TN/KY and WV/southern OH will progress into an increasingly favorable thermodynamic and kinematic environment downstream, yielding many supercells capable of producing large hail, damaging winds, and tornadoes. Upscale growth into several linear clusters with embedded supercells is anticipated this afternoon as convective coverage becomes widespread from PA/MD south-southwest across the southern Appalachian states. Forecast soundings suggest the greatest tornado threat will probably exist across eastern KY/TN northeast across southern/eastern WV, western VA, central MD and into southeast PA. Given the supercell wind profiles, significant severe wind gusts will also be possible on a localized basis. Across the Southeast, aided by a separate mid-level speed max, linear clusters of storms will continue to develop and spread generally eastward across parts of the TN Valley toward the southern Appalachians and Carolinas, with damaging winds as the most common hazard. ....Central High Plains... No changes warranted for this region. A 50-60 kt mid-level speed max should become centered near the NE/CO/KS border vicinity by late afternoon with approach of a low-amplitude shortwave impulse currently over southeast ID. This will overlap a confined north/south-oriented corridor of moderate buoyancy with MLCAPE of 1500-2500 J/kg along a lee trough across the similar tri-state area. Initial high-based thunderstorm development is anticipated off the higher terrain of CO/WY and will intensify as it impinges on the larger buoyancy during the early evening. A few supercells with very large hail will be possible along with a meso-beta scale corridor favorable for a tornadic supercell or two. Clustering of supercells may yield a short-duration uptick in severe wind gust potential across parts of western KS before convection spreads away from the relatively narrow instability plume and encounters increasing MLCIN after sunset. ....Southern High Plains... A wind-driven Slight Risk has been introduced for portions of eastern New Mexico into the Texas South Plains for later this afternoon and evening. Strong westerlies, particularly by August standards, and a hot/well-mixed boundary layer should support at least some severe storms capable of severe-caliber wind gusts. ...Guyer/Wendt.. 08/07/2023 $$ = = = 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) .