Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jul 07 2025 05:52:52 ACUS01 KWNS 070552 SWODY1 SPC AC 070550 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Jul 07 2025 Valid 071200Z - 081200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF WESTERN/CENTRAL NEBRASKA...SOUTH-CENTRAL SOUTH DAKOTA...NORTHEAST COLORADO...AND FAR NORTHWEST KANSAS... ....SUMMARY... Scattered severe storms are likely across the central into northern Plains. Severe wind gusts and large hail are the main threats. Isolated damaging winds are also possible across parts of the Lower Great Lakes, Upper Ohio River Valley, and the Northeast. ....Central High Plains into the northern Plains... A low-amplitude midlevel trough and related belt of 40-50-kt midlevel westerlies will track eastward across the northern Plains during the day. At the same time, a cold front extending southward from the northern Plains into the central High Plains will move eastward during the afternoon. Thunderstorms are expected at the intersection of the cold front and a lee surface trough over the central High Plains during the afternoon -- aided by peripheral large-scale ascent accompanying the midlevel trough. Ahead of the evolving storms, a corridor of steep midlevel lapse rates/strong surface-based buoyancy and 40-50 kt of effective shear will promote supercells and organized clusters. Large to very large hail and severe wind gusts will be possible with the initial storms. Current indications are that this activity will organize into one or more organized clusters, capable of producing swaths of severe wind (some 75+ mph). Given steep deep-layer lapse rates, lingering surface boundaries, and sufficient hodograph curvature, a couple tornadoes will also be possible. Farther north, stronger forcing for ascent accompanying the midlevel trough will support scattered thunderstorm development along the front from the Dakotas into the Upper MS Valley during the afternoon. Around 40 kt of front-orthogonal deep-layer shear will favor a mix of organized clusters and supercells, capable of producing large hail and severe wind gusts. With time, these storms may grow upscale into an east-southeastward-moving MCS, with an increasing severe-wind risk. ....Upper OH River Valley, Lower Great Lakes, and the Northeast... Widely scattered thunderstorms are expected along/ahead of a slow-moving cold front extending from the Northeast into the Lower Great Lakes/Upper OH River Valley during the afternoon. Around 30 kt of effective shear (stronger over New England) amid a diurnally destabilizing boundary layer will allow for loosely organized multicell clusters capable of producing wind damage. ...Weinman/Guyer.. 07/07/2025 $$ = = = 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) .