ACUS01 KWNS 061240
SWODY1
SPC AC 061238

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0738 AM CDT Wed Aug 06 2025

Valid 061300Z - 071200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN/CENTRAL PLAINS TO THE MID-MISSISSIPPI VALLEY. AND PART
OF NORTHERN MINNESOTA...

...SUMMARY...
Isolated strong to severe thunderstorms are possible across parts of
the northern/central Plains to the Mid-Mississippi Valley, and over
part of northern Minnesota today and tonight.

...Northern/Central Plains into the Mid MS Valley...
An MCS continues to push southward across the Mid MO Valley this
morning. The current motion, particularly the westward backbuilding
of storms into more of east-central NE, have oriented this system
favorably to a moist low-level jet, which should support maintenance
of this line for the next few hours. Echo tops within this system
remain fairly cool and occasionally strong updrafts have persisted
for the last several hours. Additionally, a notable rise/fall
pressure couplet exists with this system, as sampled by the +4 mb
pressure rise as SUX. These factors indicate the MCS remains mature
and could still occasionally produce damaging gusts over the next
few hours across southeast NE, southwest IA, northwest MO, and far
northeast KS. This MCS should begin to weaken later this morning
when the low-level jet weakens.

The region will be within the mostly zonal flow between the upper
ridging centered over NM and a shortwave trough moving through SK
and MB. Some rising heights are possible during the second half of
the period as the pattern amplifies ahead of a shortwave trough
moving into the northern Rockies. A belt of stronger mid-level flow
(i.e. around 40 kt at 500 mb) will extend across the region, and
diurnal heating of the moist airmass in place will foster moderate
to strong buoyancy. The resulting combination of buoyancy and shear
would favor strong to severe thunderstorms, but the satellite
imagery lacks any notable disturbances upstream and the large-scale
ascent is nebulous. The surface pattern also lacks any well-defined
features, with only weak troughing sampled from the central Dakotas
to a weak low over northeast CO.

As such, when and where convective initiation occurs, if it occurs
at all, is uncertain. Convective initiation appears most likely near
the Black Hills into western NE within southeasterly low-level
upslope flow within a very moist/unstable airmass. Environmental
conditions support supercells with a conditional risk for large hail
and damaging winds. However, given the uncertainty regarding
coverage, will maintain Marginal risk (level 1 of 5).

...Northern MN...
A few storms may develop along the southern periphery of the
Canadian Prairies shortwave upper trough and surface low. Lapse
rates will be weaker across this area and the favorable
thermodynamic environment will be narrow. Any stronger storms will
likely remain close to the international border, but could produce
locally strong gusts or marginal hail.

..Mosier/Bentley.. 08/06/2025

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