Subj : HVYSNOW: Probabilistic He
To   : All
From : Mike Powell
Date : Fri Oct 03 2025 09:34:44

FOUS11 KWBC 030808
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
408 AM EDT Fri Oct 3 2025

Valid 12Z Fri Oct 03 2025 - 12Z Mon Oct 06 2025

....Northern Rockies...
Days 2-3...

A pair of shortwaves moving across the Intermountain West will
interact with well above normal amounts of atmospheric moisture in
the area to cause the area's first winter storm of the season at
the higher elevations from Glacier NP in northern Montana south and
east through the ranges of northern and western Wyoming through
Sunday. The first shortwave begins the period Saturday morning over
Utah, and then tracks northeast towards the northern Plains by
Sunday morning. As the stronger of the two shortwaves getting first
dibs at the excess moisture across the area, expect heavier and
longer duration snow across the ranges of far southern Montana and
northwestern Wyoming, including Yellowstone and Grand Teton NPs.
Snowfall amounts of 6-12 inches are expected at the highest
elevations where the snow is most persistent.

As that first shortwave tracks into the Plains Sunday morning, the
second shortwave rounding the back of the longwave trough will dive
southeastward out of Alberta through much of Montana from Saturday
night through much of the day on Sunday. This shortwave will result
in a period of heavy snow across much of Glacier NP late Saturday
night through Sunday morning. This secondary forcing will keep the
snow that began with the first shortwave Saturday ongoing through
Sunday. The snow will end from north to south Sunday and Sunday
night. WPC probabilities for more than 6 inches of snow remain over
50% for the Beartooth and Absaroka Ranges.

The probability of significant icing is less than 10 percent.

Wegman



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