SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Thu Aug 07 2025
Valid 072000Z - 081200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE NORTHERN PLAINS....
...SUMMARY...
Scattered severe thunderstorms are expected later today into tonight
across the northern Plains. The most likely corridor is centered on
North Dakota, where a few tornadoes, very large hail, and a
conditional risk for significant severe gusts are possible.
...20z Update Northern Plains...
Early afternoon surface and satellite observations show low-level
convergence increasing along the intersection of an outflow
boundary/composite front and weak lee low over eastern MT. Along and
south of the front, strong diurnal heating should gradually
destabilize a very moist air mass with dewpoints in the low 70s F.
Large to extreme CAPE is expected, owing to steep mid-level lapse
rates, though with some capping likely to remain in place with
southward extent. Rapid thunderstorm initiation appears probable
this afternoon along the low-level convergence zone and in the
higher terrain farther west as a shortwave trough proceeding the
primary mid-level wave over the Northern Rockies ejects eastward.
Initial storm mode is likely to be supercellular along or on the
immediate cool side of the surface boundary. This would initially
favor a large hail risk (some significant), and the potential for a
few tornadoes, should storms become surface based.
Tonight, the primary uncertainty continues to be small-scale storm
dynamics governing upscale growth and the potential for bowing
MCS/rear-inflow jet development. Should this occur relatively early
on in the convective evolution (as shown by some CAMs), significant
damaging winds (Gusts 80+ mph) are possible across portions of ND/SD
through tonight. However, this remains highly uncertain and
conditional. Regardless of the initial evolution, significant ascent
from the primary upper trough ejecting eastward appears robust
enough to support upscale growth with any ongoing convection and
additional storms emanating from eastern MT later tonight. This
could result in one or more clusters of strong storms capable of
damaging gusts, hail and a tornado or two. Given recent trends, have
shifted the northern bound of the level 3 Enhanced northward and
eastward across ND/MN for significant damaging wind potential.
Otherwise, see MCD #1896 and #1897 for short-term information.
..Lyons.. 08/07/2025
.PREV DISCUSSION... /ISSUED 1114 AM CDT Thu Aug 07 2025/
...Eastern MT/Dakotas/Western MN...
A large upper trough is digging into the Pacific Northwest region
today, with several shortwave perturbations tracking from the
northern Great Basin into MT/ND. One feature is currently over
eastern MT and has been fostering scattered thunderstorms across
that region. Convection in this area is currently in a diurnal
lull, but may re-invigorate later this afternoon across parts of
central ND as daytime heating/destabilization occurs. Backed
low-level winds, dewpoints in the 70s, and high CAPE values will
promote a favorable environment for a few supercells capable of very
large hail, a few tornadoes, and damaging wind gusts. These storms
could persist into the evening, tracking into western MN.
Another shortwave trough currently over western ID will overspread
the mountains of ID/western MT this afternoon, promoting the
development of scattered strong storms. This activity should
intensify further as it moves into a very moist/unstable airmass
across southeast MT, with a consensus of CAM guidance suggesting
upscale growth into a bowing complex by early evening. As these
storms progress rapidly eastward across ND/northern SD, there
remains the potential for a swath of significant wind damage, along
with large hail and a tornado or two. Some guidance suggests the
MCS will remain severe well into the night, affecting parts of
western/central MN.
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