ACUS02 KWNS 110557
SWODY2
SPC AC 110555

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Thu Sep 11 2025

Valid 121200Z - 131200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE NORTHERN PLAINS AND THE FOUR CORNERS...

...SUMMARY...
Strong to severe storms capable of isolated severe wind gusts are
possible across the Four Corners region on Friday. Additional storms
are possible over the northern Plains and Upper Midwest Friday.

...Northern Plains and Upper Midwest...
A shortwave trough and enhanced southwesterly flow will move out of
the northern Rockies and into the northern Plains Friday as upper
ridging begins to move eastward. Associated with the approaching
trough, a weak lee cyclone along a stalled front over the Dakotas
will draw rich low-level moisture westward toward a second weak cold
front moving out of the Rockies. Modest ascent is expected much of
the day along and north of the surface low/front across northern WY,
western ND and central/eastern MT. While cloud cover and early
morning convection may temper heating somewhat, elevated buoyancy is
expected to support scattered to numerous storms through the
afternoon. With 35-45 kt of southwesterly flow aloft extending mid
and upper-level hodographs, a few elevated clusters or supercells
are possible. Steep mid-level lapse rates and favorable deep-layer
shear could support isolated hail and strong gusts with the
strongest storms, though confidence in the overall severe risk
remains fairly low given the potential for clouds and early morning
storms.

Convective coverage may increase through the evening and overnight
hours as a 35-45 kt southerly low-level jet develops over the
Plains. CAM guidance remains quite dispersive, but some solutions
show the potential for isolated severe gusts with elevated storm
clusters moving eastward across the Dakotas overnight.

A second cluster of elevated storms may be ongoing at the beginning
of the period across the eastern Dakotas/western MN associated with
a weak shortwave trough and low-level warm advection along the
stalled front. If this occurs, a low-end wind/hail threat could
exist during the morning as the shortwave continues
east/southeastward toward the Great Lakes. Buoyancy and ascent
should decrease quickly with eastward extent suggesting only a
limited severe risk.

...Four Corners...
A shortwave trough and an associated belt of stronger southwesterly
flow aloft will be present over portions of the eastern Great Basin
and central Rockies Friday. An associated cold front will also shift
eastward, impinging upon a modified monsoon air mass across northern
AZ/NM into eastern UT and western/central CO. A band of showers and
possibly a few thunderstorms are likely be ongoing early in the
period ahead of the front. While moisture content (PWATS 0.5-0.8
inches) will not be overly robust, it should be sufficient to
support weak diurnal destabilization amid cloud cover and remnant
showers/storms. Convection should gradually increase in coverage
along the front and across the higher terrain by late morning and
early afternoon. The stronger mid-level flow could allow for a few
storms to organize into mutlicell clusters or weak supercells. With
steep low and mid-level lapse rates present, strong gusts appear
possible with any sustained storms, along with small hail.

..Lyons.. 09/11/2025

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