523
ACUS02 KWNS 040558
SWODY2
SPC AC 040557

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1257 AM CDT Mon Aug 04 2025

Valid 051200Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS...

...SUMMARY...
Thunderstorms associated with a threat for severe gusts and isolated
large hail will be possible across parts of the central and northern
Plains on Tuesday.

...Central and Northern Plains...
A mid-level shortwave trough will move into the northern Plains on
Tuesday. At the surface, a trough is forecast to sharpen during the
day across the far western Dakotas. To the east of the trough, a
moist airmass will be in place across much of the northern Plains.
By afternoon, a north-to-south axis of moderate instability is
forecast to develop to the east of the surface trough from western
Nebraska northward into the western Dakotas. Within the moist
sector, model consensus suggests that MLCAPE will peak in the 2500
to 3500 J/kg range, with the overall maximum located in western
South Dakota. Low-level convergence will likely increase near and to
the east of the surface trough, with scattered convective initiation
expected near the trough in the late afternoon. These storms should
spread eastward across west-central South Dakota and southwestern
North Dakota during the late afternoon and early evening. A severe
threat appears likely.

Forecast soundings during the late afternoon across northwestern
South Dakota have supercell wind profiles, with directional shear in
the low to mid-levels, and 35 to 40 knots of 0-6 km shear. In
addition, 700-500 mb lapse rates are forecast to be near 8 C/km.
This environment would favor isolated large hail with rotating cells
that remain discrete. A potential for severe wind gusts will also be
possible, mainly with short line segments that form within a
larger-scale cluster. The severe threat should persist into the mid
evening, and could extend southward into northern Nebraska. However,
severe threat magnitude is expected to be more isolated with
southward extent, mainly due to more limited large-scale ascent.

Further north into parts of north-central North Dakota and westward
into northeast Montana, an isolated severe threat will be possible
during the late afternoon and early evening. However, the
combination of instability and deep-layer shear is expected less
favorable than in areas to the south. This will likely keep any
severe threat localized.

..Broyles.. 08/04/2025

$$