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FOUS11 KWBC 220732
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
232 AM EST Sat Nov 22 2025

Valid 12Z Sat Nov 22 2025 - 12Z Tue Nov 25 2025


...Southern Rockies...
Days 1-2.5...

An upper-low just west of Baja California will move eastward today
and northeastward tonight, spreading rain and high mountain snow
across AZ then into CO/NM tomorrow. Healthy subtropical moisture
will be directed at the Southern Rockies at the same time as
diffluent flow aloft supports upper-level ascent atop the
atmosphere. Upslope enhancement into some of the mountain ranges
such as the Gila Mountains, the San Juans, and the Sangre De Cristo
will aid in producing modest snow totals for the mountain peaks.
The upper low will cross over the Four Corners region and bring
heavier snow to the San Juans and Sangre de Cristos, but at high
elevations. Snow will taper off on Monday as the upper low slowly
fills.

Given the lack of a cold antecedent air-mass, snow levels will
struggle to dip much lower than 7,000ft. Elevations above 9,000ft
in the Mogollon Rim and Gila Mountains and the more remote
elevations above 10,000ft in the San Juans and Sangre De Cristos
will see the heaviest snow. WPC probabilities for at least 8 inches
of snow are >50% above about 11,000ft in the more remote/higher
ridge lines of the San Juans and Sangre De Cristo range. WPC
probabilities are low-to-moderate (20-50%) for storm total snowfall
>8" over the White Mountains in eastern AZ.

...Pacific Northwest & Northern Rockies...
Days 1-3...

A Pacific disturbance embedded within quasi-zonal flow will usher
in a progressive, but potent, frontal system into WA/OR/ID and
northwestern MT Sunday. As the cold front traverses the Pacific
Northwest, snow levels around 5000-6000ft Sunday afternoon will
drop to as low as 2,000ft on the windward side of the Cascades by
early Monday as precipitation begins to taper off. WPC
probabilities for >4" of snow do range between 30-60% in both
Stevens and Snoqualmie Passes, with potentially upwards of 6"
possible.

Snow will also spread across northern ID into northwestern MT late
Sunday and through Monday as moisture associated with the Pacific
system moves through. Additional heavy snowfall along the Lewis
Range on Monday may be enhanced by easterly upslope flow due to
strengthening high pressure to the north. WPC probabilities for at
least 8 inches of snow are >50% across the Lewis Range and above
7000ft where more than a foot of snow is possible at the highest
elevations.

...Northeast...
Day 2...

A clipper system rotating beneath the base of an broad upper-low
over Quebec will push quickly through northern NY/New England
Sunday afternoon/evening and exit to the east by Monday morning.
QPF and therefore snowfall may be somewhat limited due to its fast
movement, but some upslope enhancement may yield a bit more than
2-3" of snow across the Tug Hill, Adirondacks, and both the Green
and northern White Mountains. WPC probabilities for at least 4
inches of snow are low (10-40%) in these areas generally above
15000-2000ft.


The probability of significant ice across the CONUS is less than
10 percent.

Fracasso/Mullinax


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