ACUS01 KWNS 041233
SWODY1
SPC AC 041231

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0731 AM CDT Thu Sep 04 2025

Valid 041300Z - 051200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN PARTS OF THE
EAST AND THE MIDDLE MISSOURI VALLEY...

...SUMMARY...
Isolated damaging winds are possible across parts of the Northeast
to the southern Appalachians and Tennessee Valley from late morning
through the afternoon.  Isolated severe gusts are possible across
parts of the middle Missouri Valley late this afternoon into the
early evening.

...Southern Appalachians/TN Valley to the Northeast...
Isolated to scattered showers/thunderstorms are ongoing this morning
from the Lower Great Lakes southward into the southern Appalachians.
Water-vapor imagery shows a vertically stacked cyclone over Ontario
with a disturbance rotating through the basal portion of the larger
scale trough.  This mid-level feature will quickly move from the
upper OH Valley into the NY/central Appalachians by the late afternoon.

Despite weak mid-level lapse rates, some diurnal heating ahead of
this activity should yield gradual intensification of thunderstorms
and increased storm coverage by late morning across parts of the
southern Appalachians.  Locally damaging winds and marginally severe
hail are possible, centered on the eastern TN vicinity.

Isolated to scattered multicell clusters and short-line segments may
also evolve in the afternoon from convection along/ahead of the cold
front and lee trough.  Weak MLCAPE and poor mid-level lapse rates
will temper convective vigor, with damaging wind potential locally
augmented to where pockets of deeper boundary-layer heating occur.

...Mid-MO Valley...
An intense mid-level speed max/shortwave trough will quickly move
from the southern part of the Prairie provinces into the mid MO
Valley by this afternoon, before moving into the southwest Great
Lakes by early Friday morning.  Some model spread exists on the
magnitude of destabilization immediately ahead of a cold front
forecast to sweep through the region late this afternoon into the
evening.  However, weak buoyancy appears likely to develop and
low-level lapse rates may become adequately steep to support a
narrow corridor of low-topped storms capable of isolated severe gusts.

...KS...
An accelerating and sharpening cold front will sweep south across
the central High/Great Plains tonight. Undercut/elevated convection
should form to the cold side of this boundary early Friday morning.
Locally strong surface gusts may accompany this activity amid robust
low-level northerlies.

..Smith/Bentley.. 09/04/2025

$$
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