489
ACUS02 KWNS 060603
SWODY2
SPC AC 060601

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0101 AM CDT Wed Aug 06 2025

Valid 071200Z - 081200Z

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

...SUMMARY...
Scattered severe thunderstorms are possible Thursday afternoon and
evening across the northern Plains. Isolated very large hail and
severe gusts will be the primary threats.

...Northern Plains...
A mid-level shortwave ridge will move eastward across the northern
Plains on Thursday, as southwesterly flow becomes established across
the northern High Plains. At the surface, a low will deepen in
western South Dakota, as a cold front moves southward across western
North Dakota. To the southeast of the front, a moist and unstable
airmass will be in place across most of the northern Plains. Surface
dewpoints across this airmass should be from the mid 60s to the
lower 70s F. Ahead of the front and near the surface low, an axis of
strong instability is forecast to develop over the western Dakotas
by afternoon. Isolated convective initiation will likely take place
near the instability axis and front in the afternoon. Surface-based
thunderstorms are expected to develop and move eastward across the
northern Plains during the late afternoon and evening. A severe
threat appears likely.

Forecast soundings near the instability axis at 21Z are impressive,
with MLCAPE near 5000 J/kg, 0-6 km shear around 40 knots, and
700-500 mb lapse rates near 8.5 C/km. This environment will be
favorable for supercells with large hail. Hailstones greater than 2
inches in diameter will be possible with the more intense cores. A
potential for severe gusts will also exist, with a greater threat in
the evening if cells can congeal into a short line segment. An
isolated tornado threat could also develop. Any severe threat is
expected to persist into the mid to late evening.

Further to the east-southeastward into Minnesota, and southward into
South Dakota, large-scale ascent is forecast to be weak. For this
reason, convective coverage is forecast to be limited. However,
isolated convection could initiate along zones of low-level
convergence and maximized surface heating. Any cell that could
develop and persist, could obtain an isolated threat for hail and
severe gusts.

...Montana...
A mid-level trough will move eastward across the northern Rockies on
Thursday, as the exit region of an associated jet max moves into the
northern High Plains. The western edge of a moist and unstable
airmass will likely be in place across parts of central Montana,
where model forecast suggest MLCAPE could reach the 1200 to 2500
J/kg range. Convective initiation is expected in the higher terrain
of west-central Montana, and this activity will move eastward into
the stronger instability during the evening. Additional storms
appear likely to develop in northeastern Montana during the mid to
late evening, within an upslope flow regime. In addition to the
instability, moderate to strong deep-layer shear will be in place
over the northern High Plains, mainly due to influence of the
mid-level jet. This environment should be favorable for severe
storms, with large hail and severe gusts possible in the late
afternoon and evening.

..Broyles.. 08/06/2025

$$