Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Aug 28 2024 05:49:03 ACUS01 KWNS 280548 SWODY1 SPC AC 280547 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Wed Aug 28 2024 Valid 281200Z - 291200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE OHIO VALLEY/MIDDLE ATLANTIC AND OVER THE DAKOTAS... ....SUMMARY... Severe thunderstorms are expected from the Ohio Valley to the northern Mid-Atlantic coast, and across parts of North and South Dakota. ....Ohio Valley/Middle Atlantic... Upper ridge is gradually breaking down over the Ohio Valley, as heights are suppressed along the southern fringe of stronger flow, in association with a progressive short-wave trough. Additionally, a weak disturbance is currently located over northern MO which should advance into Indiana by 18z. Aforementioned Great Lakes short-wave trough will encourage a surface boundary to sag south into the OH Valley by mid day. This boundary will likely serve as the primary focus for robust convective development later today. Early this morning, leading edge of a larger complex of convection has advanced into northwest OH. This activity will propagate downstream into western PA later this morning, and some intensification may occur along the leading edge of the MCS carcass as boundary-layer heating aids destabilization. If so, this activity would progress southeast toward MD/DE/southern NJ with an attendant risk for primarily wind. Upstream, a secondary corridor of robust convection should evolve ahead of the northern MO disturbance that tracks into IN by midday. Strongest corridor of instability will extend across southern IL into central OH ahead of this feature/surface front. While deep-layer flow will remain seasonally weak, damaging winds along with some hail risk will be noted with this robust convection. Convective temperatures will be breached early, and surface-based updrafts may begin to organize by 17-18z. ....Dakotas... Strong short-wave trough will migrate across the northern Rockies into eastern MT by 29/12z. 60-120m, 12hr mid-level height falls will develop ahead of this feature across eastern MT/western ND during the latter half of the period. This strong short wave will result in a pronounced surface front that will surge into the western Dakotas by 18z, then into the eastern Dakotas by the end of the period. Very strong surface heating is forecast across the High Plains of SD extending into extreme southern ND. This will result in a narrow corridor of strong buoyancy by early afternoon, but capping will hold until 22-23z as temperatures warm through the mid 90s. NAM forecast sounding for PIR at 23z exhibits negligible inhibition with ample 0-6km shear for supercells and very steep lapse rates. Models also suggest LLJ will strengthen ahead of the front, and this will support organized, longer-lived updrafts. Scattered supercells should evolve ahead of the front, and will pose a risk for very large hail and damaging winds. A tornado can not be ruled out with early evening supercells. ...Darrow/Squitieri.. 08/28/2024 $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .