SPC Jun 28, 2025 1630 UTC Day 1 Convective Outlook

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

StormPrep