ACUS02 KWNS 280554
SWODY2
SPC AC 280553

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1253 AM CDT Fri Aug 28 2026

Valid 291200Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
NORTHERN GREAT BASIN AND NORTHERN PLAINS...

...SUMMARY...
Scattered severe storms are possible across parts of the northern
Great Basin and the northern Plains. Severe wind gusts are the main
threat.

...Synopsis...
The upper ridge that has remained stagnant across the Southwest into
the central U.S. will gradually drift toward the MS Valley tomorrow
(Saturday), resulting in the progression and amplification of a
mid-level trough over the Intermountain West. A surface lee trough
will gradually intensify east of the Rockies, with some potential
for surface low development over the northern High Plains. A belt of
stronger mid-level flow associated with the aforementioned upper
trough will overspread a relatively moist low-level airmass across
portions of the northern Rockies to the northern Plains. As such,
adequate buoyancy and vertical wind shear will be in place to
support at least scattered strong to potentially severe
thunderstorms Saturday afternoon.

...Portions of the northern Rockies to the northern High Plains...
A broad belt of 40-50 kt 500 mb flow will overspread the northern
Great Basin to ND through Saturday afternoon and evening, yielding
elongated, mainly straight hodographs. Furthermore, the approach of
the aforementioned upper trough will promote adequate QG ascent for
at least scattered thunderstorm development from the northern Great
Basin to the Dakotas. A relatively mixed boundary layer beneath the
broader region of stronger flow aloft and accompanying speed shear
will encourage at least isolated severe gust potential, hence the
introduction of broad Marginal Risk probabilities.

Across northern portions of the Great Basin, a relatively focused
corridor of severe wind potential exists immediately ahead of the
upper trough, where QG ascent will be strongest. NAM and RAP
forecast soundings disagree somewhat on thermodynamic profiles
across this region. RAP shows the presence of richer low-level
moisture (i.e. dewpoints over 60 F), amid 7.5+ C/km mid-level lapse
rates and over 2000 J/kg MLCAPE. Meanwhile, NAM depicts upper 40s F
low to 50s F dewpoints and slightly less steep mid-level lapse
rates. Nonetheless, both guidance members agree on showing over 1000
J/kg peak MLCAPE amid elongated hodographs and 40+ kts of effective
bulk shear, suggesting the potential for supercells. As such, a
Category 2/Slight Risk was introduced.

Across the Dakotas, immediately west of a surface low, scattered
thunderstorms are expected to develop amid moist low-level upslope
flow along the higher terrain. While mid-level lapse rates are not
expected to be overly steep in this region, these storms will
develop amid elongated hodographs and 40+ kts of effective bulk
shear, with supercell structures possible. Severe wind and hail are
currently the main hazards expected with these storms, with a Slight
Risk introduced.

..Squitieri.. 08/28/2026

$$
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