SPC Jun 27, 2025 1630 UTC Day 1 Convective Outlook

SPC 1630Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1114 AM CDT Fri Jun 27 2025

Valid 271630Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
FROM NORTHERN IN INTO SOUTHEAST LOWER MI...AND THIS
AFTERNOON/TONIGHT ACROSS THE NORTHERN PLAINS...

...SUMMARY...
Scattered thunderstorms are expected late this afternoon/evening
across the Dakotas and Nebraska, where very large hail, severe
outflow winds, and a few tornadoes will be possible.  Occasional
wind damage will be possible this afternoon from northern Indiana
into southeast Lower Michigan.

...Dakotas/NE/MN...
Water vapor imagery shows a fast-moving shortwave trough moving
across MT.  As this feature overspreads the northern Plains this
afternoon/evening, scattered thunderstorm development is expected
from western ND into central/western SD.  Storms will track
southeastward in a moist and very unstable air mass, where steep
mid-level lapse rates and sufficient vertical shear will support the
development of supercells.  Very large hail and a few tornadoes are
possible with this early activity.  Congealing outflows after dark
may result in one or more bowing segments capable of severe wind
gusts.  Have expanded the SLGT a little farther east into MN to
account for various morning CAM solutions.

...Lower MI...
Visible satellite imagery shows clear skies from northern IN into
southeast Lower MI, with dewpoints in the 70s and afternoon CAPE
values expected in the 2000-3000 J/kg range.  A weak shortwave
trough will pass to the north of this area, providing weak lift and
aiding in thunderstorm development by mid afternoon.  Steep
low-level lapse rates will promote a risk of damaging wind gusts in
the stronger cells.

...East TN/north GA...
Another active day of scattered thunderstorms is expected, with
hot/humid conditions aiding in the risk of locally damaging wind
gusts and some hail in the stronger cells.

..Hart/Grams.. 06/27/2025

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