Severe Storm Outlook Narrative (AC)
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975
ACUS02 KWNS 101720
SWODY2
SPC AC 101718

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1218 PM CDT Sun Aug 10 2025

Valid 111200Z - 121200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE MONDAY
AFTERNOON AND EVENING ACROSS  PARTS OF EASTERN NORTH
DAKOTA...NORTHWESTERN MINNESOTA...EAST CENTRAL NEW MEXICO AND
NORTHWESTERN TEXAS...

...SUMMARY...
Strong thunderstorms accompanied by at least some risk for severe
wind and hail may impact parts of eastern New Mexico into the Texas
South Plains, as well as  parts of eastern North Dakota into
northwestern Minnesota, late Monday afternoon and evening.

...Discussion...
While the westerlies generally remain confined to the higher
latitudes, one significant embedded short wave trough is forecast to
continue digging southeast of the Canadian Prairies through the
international border vicinity, to the west of the Great Lakes,
during this period.  It appears that this will be accompanied by one
initial surge of cooler/drier boundary layer air across much of the
Dakotas and portions of the Upper Midwest/adjacent Great Lakes
region by late Monday night.

Otherwise, weak mid-level troughing likely will linger across much
of the remainder of the interior U.S., to the east of the Rockies,
between large-scale mean ridging centered offshore of both the
Pacific and Atlantic coasts.  An associated weak surface frontal
zone, still reinforced by convective outflow in some locations, is
likely to linger across the Great Lakes through lower Missouri
Valley and Texas South Plains into early Monday, before generally
continuing to weaken through the period.

Seasonably high boundary-layer moisture content probably will be
maintained ahead of the stalled/slow moving remnant front, across
much of the Southwest, as well as in a corridor along and to the
north it.  Some of this moisture across the lower/middle Missouri
Valley may begin to advect northward ahead of the lead reinforcing
cool intrusion late Monday into Monday night.

...Southern Great Plains into Great Lakes...
The seasonably high boundary-layer moisture content, along/just
north of the weakening front, may provide support for the
development of moderate to locally higher CAPE with insolation
Monday.  As this occurs, it appears that a number of convectively
generated or augmented perturbations within the generally weak
southwesterly deep-layer mean flow could contribute to scattered
thunderstorm development during and after peak heating. Some of this
could pose a risk for localized potentially damaging wind gusts, but
the coverage of any such activity still seems likely to remain
rather sparse in nature.

One possible exception may develop along a modifying segment of the
boundary across parts of east central New Mexico into the Texas
South Plains by late Monday afternoon or evening, beneath steeper
mid-level lapse rates associated with the remnants of a plume of
warm elevated mixed-layer air.  There appears a general consensus
within the various model output that a digging short wave impulse,
within a weak northwesterly mid-level regime, may provide support
for a relatively notable upscale growing/southeastward propagating
thunderstorm cluster.

Farther northeast, the NAM, perhaps more so than other model output,
suggests that a notable MCV may emerge from Sunday night convection
over the central Great Plains, before slowly migrating across the
lower Missouri Valley toward the Great Lakes Monday through Monday
night.  It is possible that a perturbation of the strength suggested
by the NAM could, at some point, support another notable evolving
cluster with potential to produce strong wind gusts.  At this point,
however, the potential for this still seems low, with too much
uncertainty to introduce 5 percent probabilities without unduly
large false alarm area.

...Northern Great Plains...
A moistening boundary-layer, aided by evapotranspiration and perhaps
the onset of better low-level moisture return on strengthening
southerly low-level flow, may contribute to moderate CAPE within a
corridor of stronger pre-frontal surface heating by late afternoon.
Coupled with strengthening deep-layer mean wind fields and shear,
downstream of a digging 50+ kt 500 mb jet, it appears that the
environment may become conducive to vigorous convective development
capable of producing small to marginally severe hail and strong
surface gusts.  Potential for gusts approaching or exceeding severe
limits appears highest during the late afternoon and early evening
across parts of eastern North Dakota into northwestern Minnesota,
where warm, unsaturated low-level thermodynamic profiles with steep
lapse rates will aid downward momentum transfer via enhanced melting
and evaporative cooling in downdrafts.

..Kerr.. 08/10/2025

$$