Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jun 29 2025 20:04:05 ACUS01 KWNS 292002 SWODY1 SPC AC 292000 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Sun Jun 29 2025 Valid 292000Z - 301200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL PLAINS INTO THE MIDDLE MISSISSIPPI VALLEY...AND OVER PARTS OF THE UPPER MIDWEST... ....SUMMARY... Isolated to scattered strong to severe thunderstorms are possible from the upper Great Lakes into the central High Plains. Wind is the primary risk, though hail is expected across portions of the High Plains. ....20Z Update... The Slight risk was expanded southeastward from parts of the central Plains into the Middle MS Valley, where a cluster of thunderstorms is intensifying as it impinges on a strongly unstable air mass. The primary concern with this activity is damaging wind gusts. For information on the severe risk here, reference Severe Thunderstorm Watch 478. Additionally, 2-percent tornado probabilities were added along this corridor and westward into southeast/south-central KS and far northeast/north-central OK. Here, antecedent outflow is diurnally destabilizing amid rich boundary-layer moisture. Clockwise-curved low-level hodographs will support a localized tornado risk with any cells that can develop in this corridor. Farther west, significant-wind probabilities were added over northwest KS, southwest NE, and far eastern CO. Any thunderstorm clusters that evolve out of CO and move through this area will have the potential of producing gusts upward of 75 mph -- aided by steep deep-layer lapse rates and sufficiently elongated hodographs. Additionally, visible satellite imagery shows a shallow boundary-layer cumulus field along a surface wind shift in this general area. As storms move into this area of enhanced moisture and steep lapse rates, a brief tornado will be possible. Reference Severe Thunderstorm Watch 477 and MCD 1508 for the severe risk in the Upper Midwest, and MCDs 1509 and 1510 for the High Plains severe risk. ...Weinman.. 06/29/2025 ..PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Jun 29 2025/ ....Eastern KS/Western MO... An overnight MCS is slowly weakening over central MO, with an associated outflow boundary extending from eastern KS into south-central MO. Strong heating will occur along and south of the boundary, where several 12z CAM solutions indicate development of afternoon thunderstorms. Given this scenario, have extended the SLGT risk farther south into this region. Locally damaging wind gusts would be the main concern. Refer to MCD #1506 for further short-term details. ....WY/CO/SD/NE... A low-amplitude shortwave trough is digging into WY. As forcing associated with this system overspreads the High Plains of WY, high-based convection is expected. Thunderstorms will intensify as they track into a moderately unstable air mass and weak but backed low-level flow. Severe storms capable of large hail and damaging winds may affect the Black Hills region and southward into the NE Panhandle. Storms will also develop southward into the foothills of CO this afternoon and spread eastward. Winds and temperatures aloft are less favorable for organized/severe storms that far south, but at least isolated instances of large hail and damaging winds are possible. ....IA/WI... Strong heating is occurring across much of WI today, where a moist air mass will lead to moderate CAPE values. Thunderstorms will develop by mid-afternoon along a remnant weak boundary across central WI/northeast IA and spread northeastward through the day. Vertical shear is not particularly strong, and overall convective organization is expected to be low. Nevertheless, steep low-level lapse rates and ample instability will promote strong downdrafts and some hail in the strongest cells. $$ = = = 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) .