LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1200 PM CDT Sun Jul 27 2025
Valid 271630Z - 281200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS
SOUTHERN/EASTERN MINNESOTA AND FAR EASTERN SOUTH DAKOTA...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
MID-ATLANTIC STATES...
...SUMMARY...
Severe thunderstorms are expected this afternoon and evening across
parts of the Upper Midwest to western Great Lakes. Other severe
storms will also be possible in parts of the northern Plains,
central Appalachians, and Mid-Atlantic.
...Upper Midwest/western Great Lakes including MN/eastern SD...
A convectively enhanced mid-level shortwave trough over
northern/eastern North Dakota will continue generally eastward
toward northern Minnesota, with a modest flattening of the
downstream upper-level ridge into tonight. A modest deepening of the
surface low will occur across eastern South Dakota toward the
southwest Minnesota border vicinity, with intense thunderstorm
development later today generally expected to focus along the
southeastward-advancing front, although differential heating and a
convectively aided cluster/possible MCV across northeast South
Dakota at midday may also be factors.
Given the strong buoyancy near/south of the front, and very steep
lapse rates/elevated mixed layer impinging from the west-southwest,
modestly strong wind profiles will be sufficient for intense
supercell development with initial storms, including large hail
potential (higher magnitudes possible especially eastern South
Dakotas and southwest Minnesota) and some tornado risk. Multiple
southeastward-moving clusters should evolve this evening with an
increasing likelihood of damaging wind across southern Minnesota
into western/northern Wisconsin. Portions of the region have been
upgraded to an Enhanced Risk.
...Mid-Atlantic/Central Appalachians...
Scattered afternoon thunderstorms will continue to increase
regionally. Similar to previous days, mid-level lapse rates will be
weak and considerable mid-level moisture will keep the overall
potential somewhat limited/isolated. However, the strongest cells
will be capable of occasional gusty/damaging winds, with a somewhat
higher probability of wind damage seemingly existing across eastern
Virginia where buoyancy will be greater.
...Montana...
Strong heating will occur this afternoon across much of
central/eastern Montana, where deep boundary-layer mixing will lead
to inverted-v profiles. Scattered thunderstorms are forecast to
develop along a corridor from southwest into central Montana by late
afternoon. These high-based storms may pose a risk of a few
severe-caliber wind gusts.
..Guyer/Thornton.. 07/27/2025
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