Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jul 13 2024 17:32:10 ACUS02 KWNS 131732 SWODY2 SPC AC 131730 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Sat Jul 13 2024 Valid 141200Z - 151200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS INTO WESTERN MINNESOTA... ....SUMMARY... Strong to severe thunderstorms are possible from the northern Plains into the Upper Midwest on Sunday. ....Synopsis... An upper shortwave trough over the upper Great Lakes is forecast to develop east toward NY/southern New England Sunday into early Monday. Meanwhile, an upper anticyclone is forecast to persist over the Four Corners and southern Rockies vicinity, with a subtropical high extending into the Southeast. A belt of enhanced northwesterly upper level flow will stretch from MT into the northern Plains/Upper Midwest vicinity. Several shortwave impulses are forecast to migrate through this area of northwesterly flow through the period. Some more appreciable height falls are possible Sunday night/early Monday as a compact upper shortwave trough migrates across the Canadian Prairies toward ND and the Upper Midwest. This area of northwesterly flow aloft and the aforementioned shortwaves will focus severe thunderstorm potential on Sunday across portions of the northern Plains to the Great Lakes vicinity. ....Southern WI/Northern IL into southern Lower MI/northern OH... A seasonally moist airmass will be in place on Sunday with dewpoints in the upper 60s to low 70s. This will support moderate to strong destabilization across the Marginal (level 1 of 5) risk area. Most guidance indicates remnant convection and convectively enhanced vorticity maxima will be ongoing/located in the vicinity of southern Lake Michigan during the morning, and shift east through the period. This MCV will enhance otherwise modest vertical shear, and focus thunderstorm development through the afternoon and evening. Thunderstorm clusters will mainly pose a risk for severe/damaging gusts, though isolated hail also will be possible. Higher severe probabilities may be needed in subsequent outlooks if confidence increases in a corridor of greater storm organization. ....Northern Plains vicinity... Several surface boundaries will focus thunderstorm development across the region during the afternoon and into the overnight as the upper shortwave trough develops east/southeast toward the international border. One boundary will be draped across northern WI/MN into northwest ND. Meanwhile, a surface trough will extend southward across western ND/SD/NE before a synoptic cold front dives south/southeast across northern High Plains late in the period. Within the warm sector wedge between these boundaries, a seasonally moist and very unstable airmass will be in place. Enhanced northwesterly flow aloft amid vertically veering low-level wind profiles will result in moderate to strong vertical shear supporting supercells and organized line segments should upscale development occur. Isolated convection will likely develop during the late afternoon in the vicinity of the surface trough across the High Plains. High-based supercells capable of large hail and strong outflow gusts are expected with this initial activity. As stronger height falls occur during the evening, a modest southwesterly low-level jet and large-scale ascent will increase. More widespread thunderstorm development is expected as this occurs, and one or more lines/bowing segments may develop east/southeast across the region. While some boundary-layer stabilization occurs nocturnally, strong instability and potentially well-organized convection should be sufficient for a severe/damaging gust risk to persist into the eastern Dakotas and western MN into the nighttime hours. ...Leitman.. 07/13/2024 $$ = = = 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) .