963
ACUS48 KWNS 030859
SWOD48
SPC AC 030858

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Sun Aug 03 2025

Valid 061200Z - 111200Z

...DISCUSSION...
...Wednesday/Day 4 to Friday/Day 6...
A large-scale mid-level anticyclonic flow pattern will be in place
over much of the central and western U.S during the mid week. At the
surface, a moist and unstable airmass is forecast over the central
and northern Plains. Within the broader scale flow, a shortwave
ridge is forecast to move across the northern Plains from Wednesday
into Thursday. In spite of relatively weak large-scale ascent,
isolated thunderstorm development will be possible on Wednesday and
Thursday as instability becomes maximized in the late afternoon and
early evening. Moderate deep-layer shear should support a potential
for isolated severe gust and hail.

As the mid-level ridge moves eastward during the day on Thursday,
flow is forecast to become southwesterly across the northern High
Plains. Thunderstorms that develop in eastern Montana and western
North Dakota Thursday evening could be associated with a severe
threat. Isolated large hail and severe gusts will be possible. Model
forecasts suggest an isolated severe threat will again be possible
in the northern Plains on Friday, in the wake of the exiting ridge.

...Saturday/Day 7 and Sunday/Day 8...
On Saturday, a mid-level trough is forecast to move into the
northern High Plains, as flow remains southwesterly from the Dakotas
into the upper Mississippi Valley. Model forecasts develop a
relatively large cluster of thunderstorms Saturday evening ahead of
the trough from northwestern Minnesota into eastern South Dakota.
The models also have strong instability and moderate deep-layer
shear in place ahead of the trough within the favored convective
zone. This could support a potential for supercells with large hail
and severe wind gusts. However, the steeper lapse rates are forecast
to remain further south across the mid Missouri Valley, suggesting
there is still some uncertainty concerning the magnitude of the
severe threat.

On Sunday, the severe threat is forecast to shift southeastward as a
front moves across the region. The favored corridor would be along
an axis of moderate instability from northeast Nebraska to
northwestern Wisconsin. This position of the front and instability
axis should be determined by the timing of the mid-level system,
which is still considerably uncertain.

..Broyles.. 08/03/2025