SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Sat Jun 28 2025 Valid 281630Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON FROM CENTRAL PENNSYLVANIA INTO SOUTHEAST NEW YORK. OTHER SEVERE STORMS WILL OCCUR FROM THE BLACK HILLS REGION INTO PARTS OF MINNESOTA AND WESTERN WISCONSIN.... ...SUMMARY... Scattered severe thunderstorms are possible across portions of the Upper Midwest into the north-central Great Plains. All severe hazards are possible centered on southern Minnesota and eastern South Dakota. Scattered damaging gusts are possible across parts of New York into Pennsylvania. ...Eastern SD/MN/WI... Current radar loops show a persistent MCS slowly weakening across southern MN. This feature has driven an associated outflow boundary into northwest IA and eastern SD. Morning model solutions are in general agreement that the low-level air mass will rapidly recover in the wake of the MCS, leading to rapid and intense thunderstorm development by late afternoon over western MN. It is unclear if the models are handling the lingering effects of the morning convection, but the eventual re-development of storms poses risks of tornadoes, very large hail, and damaging winds. An upgrade to ENH risk over parts of central/southern MN for this evening was considered, but will defer to the 20z outlook, after further evaluation of the ongoing convection and trends in destabilization. ...Western SD Vicinity... Full sun will lead to strong heating and deep mixing across much of eastern WY today. High-based convection will develop by late afternoon in this region and spread eastward into a progressively more moist and unstable air mass over western SD. Scattered intense storms are expected to develop, posing a risk of large hail and damaging wind gusts. These storms may persist through the evening and grow upscale, with a risk of damaging winds into southern SD/northern NE. ...NY/PA/Mid-Atlantic... A surface cold front is sagging southward into NY and western PA today. Thunderstorms have begun to intensify along/ahead of the front, with locally damaging wind gusts expected through the afternoon. Low clouds are limiting heating/destabilization over eastern NY/PA and the Mid-Atlantic region. However, heating should commence by mid/late afternoon, allowing storms approaching from the west to maintain a damaging wind threat into the early evening. ..Hart/Squitieri.. 06/28/2025