ACUS01 KWNS 271139
SWODY1
SPC AC 271138

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0638 AM CDT Sun Jul 27 2025

Valid 271300Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY INTO THE
WESTERN GREAT LAKES REGION...

...SUMMARY...
Severe thunderstorms will be possible this afternoon and evening
from parts of the upper Mississippi Valley into the western Great
Lakes. Marginally severe storms will also be possible in parts of
the northern Plains, central Appalachians, Mid-Atlantic and eastern
North Carolina.

...Northern MN This Morning...
A persistent bowing MCS is over northern MN headed toward the
Arrowhead region.  These storms have produced locally damaging wind
gusts through much of the night, but have shown signs of weakening
on the north end of the bow during the past 1-2 hours.  One intense
cells remains on the south end of the bow, headed toward the Hibbing
vicinity.  This activity may continue to pose a risk of damaging
winds or hail for awhile this morning.

...Upper MS Valley into western Great Lakes...
A convectively aided shortwave trough is currently tracking across
ND.  This feature will move into northern MN this afternoon with an
associated surface cold front sagging into central MN.  Steep
mid-level lapse rates and strong heating ahead of the front will
result in a very unstable airmass this afternoon, with MLCAPE values
of 3000-4000 J/kg.  A consensus of CAM solutions suggests the
development of a few discrete supercells along the front by mid/late
afternoon.  These storms will be capable of very large hail and
perhaps a few tornadoes during the first couple of hours.  After
that, upscale growth is likely with damaging winds becoming the main
concern as storms build southeastward across southern MN and into
central WI.

...Mid Atlantic/Central Appalachians...
Scattered afternoon thunderstorms are expected once again today from
parts of PA/WV into VA/NC.  Similar to previous days, mid-level
lapse rates will be weak and considerable mid-level moisture will
limit overall severe concerns.  However, the strongest cells will be
capable of occasional gusty/damaging winds.

...MT...
Strong heating will occur this afternoon across much of
central/eastern MT, where deep boundary-layer mixing will lead to
inverted-v profiles.  Scattered thunderstorms are forecast to
develop along a corridor from southwest into central MT by late
afternoon.  These high-based storms may pose a risk of a few
damaging wind gusts.

..Hart/Grams.. 07/27/2025

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