Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
321 AM EDT Wed Oct 15 2025

Valid 12Z Wed Oct 15 2025 - 12Z Sat Oct 18 2025

...Central Great Basin & Northern Rockies...
Days 1-2...

A potent closed upper low, which impacted California and the Sierra
to start the week is forecast to cross the central Great Basin
today before lifting across the northern Rockies on Thursday. As it
does so, it is also forecast to gradually weaken, but still
provide ample broad scale upper ascent over the region. The
greatest potential for moderate to locally heavy snow will likely
be situated directly underneath the aforementioned upper low where
the greatest lift and steepest lapse rates exist. The 00z HREF
shows this potential for 1-2"/hr snowfall rates across the high
terrain throughout north-central and northeast NV between 18Z-00Z
today as snow levels drop as low as 7,000ft.

For the northern Rockies, strong south-southwesterly upslope flow
into the WY and UT mountain ranges will provide for more longevity
of moderate high elevation snowfall ahead of the mid-upper low on
Thursday. This includes the Tetons, Absarokas, Bighorns, Wind River
Range, as well as the Wasatch and Uintas of UT. Snow levels will
start out fairly high and around 9,000ft before dropping to around
7,000ft for areas underneath the mid-upper low as it pushes
northeastward. Snow should taper off by Thursday night as the
system quickly exits into the northern Plains and dry northwesterly
flow becomes the dominant regime again for the time being.

WPC probabilities for at least 8 inches of snow for this event are
moderate-to-high (50-80%) across the Ruby Mts of northeast NV, as
well as many of the ranges surrounding Yellowstone NP, the WY
Bighorns, and the Uintas of UT. Most of these higher probabilities
reside over regions higher than 9,000ft in elevation.


The probability of significant freezing rain across CONUS is less
than 10 percent.


Snell