Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun Jul 20 2025 19:31:41

ACUS03 KWNS 201931
SWODY3
SPC AC 201930

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 PM CDT Sun Jul 20 2025

Valid 221200Z - 231200Z

....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MIDWEST...

....SUMMARY...
Scattered strong/severe thunderstorms may impact parts of the
northern Great Plains into the Upper Midwest Tuesday into Tuesday
night, posing a risk for severe wind and hail. Damaging thunderstorm
wind gusts are also possible across parts of the Southeast.

....Northern Plains to the Upper Midwest...
Along the northwestern periphery of an expansive midlevel ridge
centered on Mid MS Valley, moderate west-southwesterly midlevel flow
will be in place from the northern Plains to the Upper Midwest --
downstream of a persistent midlevel trough over the Northwest.
Several embedded impulses should advance through the belt of
west-southwesterlies, while a surface low moves slowly eastward
across the Dakotas. Downstream of the surface low, middle/upper 70s
dewpoints beneath a steep midlevel lapse rate plume will contribute
to a corridor of extreme surface-based buoyancy along a warm-front
type feature draped across the Upper Midwest. While subtle forcing
for ascent and potential early-day convection cast uncertainty on
the overall convective scenario here, a broad/strong low-level jet
(and related warm-air advection), the extreme buoyancy, and strong
deep-layer shear will support robust/organized storms capable of
producing swaths of severe wind and hail.

Farther west over eastern MT into the Dakotas, subtle midlevel
height falls atop seasonably rich boundary-layer moisture will also
favor strong to severe storms, with a risk of severe wind gusts and
large hail.

....Southeast...
A very high PW air mass will be in place across the Southeast, where
diurnal heating will contribute to moderate surface-based buoyancy.
As a weak cold front impinges on this air mass during the afternoon,
modestly enhanced midlevel northerly flow will support loosely
organized storm clusters capable of producing damaging winds.

...Weinman.. 07/20/2025

$$

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