466
ACUS02 KWNS 041727
SWODY2
SPC AC 041726

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1226 PM CDT Thu Sep 04 2025

Valid 051200Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
OHIO AND TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS...

...SUMMARY...
Scattered thunderstorms capable of producing damaging wind gusts and
isolated large hail are expected across parts of the Ohio and
Tennessee Valleys into the Central Appalachians on Friday.

...Synopsis...
A deep/vertically stacked cyclone will move gradually northward
across Ontario toward Hudson Bay through the period, as an
accompanying midlevel jet streak advances from the Great Lakes into
Quebec. Peripheral to the deep cyclone, broad midlevel troughing
will persist across much of the eastern CONUS. An accompanying cold
front will extend from the Great Lakes region southwestward across
the OH Valley into the southern Plains. Given the slowly
evolving/amplified upper-level pattern, the cold front will only
move gradually east-southeastward through the period.

...Ohio/Tennessee Valleys into the Central Appalachians...
Ahead of the cold front, ample diurnal heating amid upper 60s
dewpoints will contribute to a moderately unstable (around 2500 J/kg
MLCAPE), uncapped pre-convective air mass. Potentially aided by a
convectively augmented midlevel impulse approaching the OH Valley
from the west, scattered thunderstorms should develop
along/immediately ahead of the front during the afternoon into
evening/overnight. The aforementioned buoyancy and around 30-40 kt
of effective shear should promote convective organization into
clusters/small line segments and perhaps transient supercell
structures. The stronger/longer-lived storms will be capable of
producing damaging wind gusts and isolated severe hail. The best
overlap of moderate buoyancy (higher with southward extent) and
favorable deep-layer shear (stronger with northward extent) should
exist over KY and surrounding states, where a Slight Risk was added.

...Mid-South into the Southern Plains...
The cold front will be oriented more west-east over this region,
with the stronger deep shear confined to the cool side of the
boundary. Additionally, convective initiation may occur later into
the evening/overnight hours along the sharpening cold front.
Nevertheless, moderate-strong buoyancy aided by steep deep-layer
lapse rates will promote strong storms capable of producing locally
damaging gusts and sporadic, marginally severe hail.

..Weinman.. 09/04/2025

$$