Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Sep 07 2024 12:25:01 ACUS01 KWNS 071224 SWODY1 SPC AC 071223 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0723 AM CDT Sat Sep 07 2024 Valid 071300Z - 081200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Organized severe thunderstorms are not forecast today, though a few strong gusts could accompany the most robust convection. ....Synopsis/Discussion... The mid/upper-level pattern will feature strong, progressive troughing over the Great Lakes and vicinity, and ridging from the Four Corners north-northwestward to the Canadian Rockies. The major synoptic trough over the Great Lakes is anchored by a cyclone initially centered over Lake Huron. The low should move erratically eastward to northeastward across ON to southwestern QC by the end of the period. As this occurs, strengthening cyclonic flow and height falls will overspread the Northeast, while cyclonic flow remains behind the low across the Great Lakes, Ohio Valley and central Appalachians. An associated surface cold front -- analyzed at 11Z from central NY across northwestern VA, easternmost TN, northern MS, north TX, and central NM -- should move eastward across NY to central/eastern New England by 00Z, extending southward offshore from most of the Mid- Atlantic Coast, and merging with a northeastward-moving surface cyclone now located offshore from SC. A separate surface cyclone (with mid/upper-level extension) now south of Nova Scotia will move northward, with peripheral isallobaric effects limiting convergence along the cold front for much of today. Still, a band of showers and embedded thunderstorms may organize enough to produce strong gusts for a couple hours this afternoon from the Hudson Valley region into NJ, the NYC area and western Long Island. At this time, weak lapse rates and low-level shear are still forecast, and organized severe-gust potential appears too low and conditional for an outlook. In the West, a weak binary cyclone (with two apparent centers in moisture-channel imagery) covers the coastal areas of OR and northwestern CA, as well as adjoining Pacific waters. This feature is devolving into an open-wave trough, and will continue to weaken through the period as it slowly moves inland. Associated large- scale ascent, overlapping diurnal/diabatic destabilization of higher terrain, may contribute to thunder potential (including dry thunder for fire-weather purposes) over portions of the interior Northwest. Northwest flow aloft, east of the ridge, will overlie a well- developed surface lee trough over eastern parts of CO/WY. Strong veering with height is expected, but with weak low/middle-level flow. Though ideally rich moisture will be well-removed from this region, over the Gulf, enough residual/post-frontal moisture should remain to support isolated to widely scattered, high-based thunderstorms this afternoon over eastern WY/CO, and perhaps this evening over southwestern NE near a strengthening LLJ. Forecast soundings show a deep, well-mixed subcloud layer that may support strong gusts from low-precip cells. However, with weak moisture and strong mixing leading to limited buoyancy (MLCAPE less than 800 J/kg), severe potential appears isolated at best, with unconditional areal probabilities remaining below 5% this outlook cycle. ...Edwards/Kerr.. 09/07/2024 $$ = = = 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) .