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

Valid 00Z Thu Oct 16 2025 - 00Z Sun Oct 19 2025

...Eastern Great Basin to North-Central Rockies...
Day 1...

Low pressure over south-central Nevada this afternoon will track
northeast over UT tonight and Wyoming on Thursday. Slight weakening
is expected, but it will remain a closed low. Ongoing banding
along the deformation axis north of the low will persist over NV
and UT through tonight (where 1-2"/hr snow rates about the 7000ft
snow level are noted in the 12Z HREF over the Ruby in NV and the
Wasatch and Uinta in UT) before shifting to the WY ranges (and
northern Absarokas in southern MT) for Thursday where rates should
be more in the 0.5 to 1"/hr range above a 7500ft snow level.

Day 1 WPC PWPF (starting at 00Z tonight) for >8" snow 30-50% for
the Ruby Mts of northeast NV, Uinta of UT, the Tetons, Wind River,
Absarokas, and Bighorns in WY.


...Northern Rockies...
Day 3...

An upper trough ejects from what is currently a low over the Gulf
of Alaska and tracks down the northern Rockies of Montana and
Wyoming late Friday through Saturday morning. This reinforcing
trough will only have rather dry continental air to work with
since it is in the wake of the system crossing Wyoming from
southwest to northeast on Thursday. However, decent lift from the
trough axis should allow some moderate snow rates Friday night
through Saturday morning in terrain from around Glacier NP, eastern
Absarokas, Bighorns, and even Laramie range. Day 3 PWPF for >2"
are 20 to 50% over these ranges and closer to 70% for the Bighorns.
Snow levels dip under the upper trough passage, to around 4000ft
in northern MT, 5000ft in northern WY, and 6000ft in southern WY.


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


Jackson