ACUS02 KWNS 120601
SWODY2
SPC AC 120600

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Fri Sep 12 2025

Valid 131200Z - 141200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
SOUTHERN AND CENTRAL HIGH PLAINS AND THE NORTHERN PLAINS...

...SUMMARY...
Strong to severe storms are possible over parts of the southern and
central High Plains and northern Plains Saturday.

...Synopsis...
The western upper trough will continue its slow progress eastward on
Saturday. The trough is expected to eject into central Plains by
early Sunday morning. A few embedded shortwave troughs will pivot
into the northern Plains and stronger mid-level winds will extend
into the southern Rockies. At the surface, a low in the northern
Plains will become more diffuse during the period.

...Southern/Central High Plains...
On the southern edge of the broad western trough, stronger mid-level
flow will be perpendicular to the southern Rockies into part of the
Front Range. Low-level moisture will advect into the regions given
surface southeasterly winds. Moisture will be greatest in New Mexico
with mid/upper 50s F dewpoints. Farther north, flow will become much
more meridional and moisture will be more limited. Within the
southern Rockies, cloud cover associated with the trough will
generally keep low-level lapse rates weak. However, modestly steep
mid-level lapse rates with the cooler air aloft and 35-40 kts of
effective shear will promote some risk for a few supercell
structures by the afternoon. Isolated large hail will be the main
risk. While a similar hail threat will be present for much of the
Front Range, this area is also more likely to receive greater
surface heating. Steeper low-level lapse rates will support a threat
for isolated severe gusts with the strongest storms.

...Northern Plains...
Scattered thunderstorms will likely be ongoing at the start of the
period. By this time, steeper mid-level lapse rates will likely have
diminished for much of the western Dakotas into eastern Montana and
Wyoming. This activity will be driven by a northward moving
shortwave trough and low-level warm advection. Despite cloud cover
complicating the low-level thermodynamic environment and the surface
low gradually weakening with time, there may still be zone of
greater potential in the eastern Dakotas where steeper mid-level
lapse rates will be. Greater shear/forcing will overlap greater
buoyancy during the afternoon in this area as well. The strongest
storms, if they develop, will likely be near and east of the
Missouri River. Small to isolated marginally severe hail appears to
be the primary hazard.

...Upper Midwest...
A weak shortwave trough is expected to move through southern
Wisconsin into the southern Lake Michigan vicinity. This will
promote a zone of warm advection that will allow potentially
scattered storms to develop. While shear will be modestly enhanced
with the shortwave, greater buoyancy and lapse rates will be
displaced to the west. A stronger storm or two could occur, but
limited confidence in greater severe storm coverage precludes probabilities.

..Wendt.. 09/12/2025

$$
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