Subj : DAY1SVR: Day 1 Convective Outlook Corr 1 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Jul 26 2024 05:33:08 ACUS01 KWNS 260533 SWODY1 SPC AC 260531 Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1231 AM CDT Fri Jul 26 2024 Valid 261200Z - 271200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON AND EVENING ACROSS PARTS OF SOUTHEASTERN ARIZONA AND ADJACENT SOUTHWESTERN NEW MEXICO...PARTS OF NORTHEASTERN NEVADA INTO WESTERN UTAH...PARTS OF WESTERN NEBRASKA AND ADJACENT SOUTHEASTERN WYOMING INTO CENTRAL SOUTH DAKOTA...AND PARTS OF EASTERN NORTH DAKOTA INTO NORTHWESTERN MINNESOTA... CORRECTED FOR GEN THUNDER LINE/NDFD GRAPHIC ....SUMMARY... The risk for severe thunderstorms appears seasonably low across much of the U.S. today through tonight. ....Discussion... A significant inland migrating mid-level trough (and embedded low) is now progressing east-northeast of the Canadian and northern U.S. Rockies, and forecast to continue eastward across the Canadian Prairies today through tonight. While stronger mid-level height falls likely remain focused well to the north of the international border area, models indicate that mid-level heights will continue to fall across much of the West into the northern Great Plains, as weak trailing troughing develops inland of the Pacific coast and downstream ridging becomes increasingly suppressed. In lower levels, to the south of a deepening surface cyclone associated with the primary short wave perturbation, a modest cold front may advance east of the northern Rockies, before stalling and weakening across the northern Great Plains into northern portions of the Great Basin. As this regime evolves, destabilization associated with strong daytime heating and remnant monsoonal moisture appears likely to support considerable thunderstorm development this afternoon and evening across the higher terrain of eastern Arizona through the southern Rockies, and near lee surface troughing across the north central high plains. Additional, more widely scattered, thunderstorm activity may focus near/just ahead of the surface front across the northern Great Basin through portions of the northern Rockies and northern Great Plains. Some of the stronger, more persistent convection will probably overspread, or develop above, more strongly heated and deeply mixed (with large developing surface temperature-dew point spreads) lower elevations, accompanied by a risk for strong to locally severe wind gusts. ....Eastern North Dakota/Northwestern Minnesota... Beneath a plume of very warm and capping elevated mixed-layer air, which will continue to advect northeastward across the northern Great Plains through the day, models indicate that seasonably moist boundary-layer air may support a narrow corridor of large potential instability across the Red River Valley vicinity into the stalling weakening frontal zone across northwestern Minnesota/southeastern Manitoba/adjacent northwest Ontario by early evening. Downstream of the base of the short wave perturbation crossing the Canadian Prairies, forcing for ascent may support isolated to widely scattered thunderstorm development. In the presence of at least 30-40 kt deep-layer shear, and modest clockwise-curved low-level hodographs, one or two supercells appear possible to the south of the international border, perhaps as far southwest as areas near/west of Grand Forks and Fargo. ...Kerr.. 07/26/2024 $$ = = = 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) .