Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
408 AM EDT Wed Oct 14 2020

Valid 12Z Wed Oct 14 2020 - 12Z Sat Oct 17 2020

Day 1...

...Pacific Northwest to the Northern Rockies...
The 150-170+ upper level jet streak and associated shortwave
energy will gradually lift east-northeast of the Pacific NW and
northern Rockies Wednesday and Thursday. The ongoing, high
elevation snowfall across the northern Rockies in northwest MT
will gradually wane today as the amplifying wave digs over the
Great Plains (and the ensuing veering, deep-layer northwesterly
flow cuts off the direct onshore moisture connection). 24 hr
probabilities of 50% or greater of at least 6 inches of snow will
be confined to the higher elevations (7000+ ft) of the far
northern Rockies in northwest MT, along with the Bitterroots along
the ID/MT border.

Day 2...

The probability of receiving at least 4 inches of snow is less
than 10 percent.

Day 3...

Another upper level shortwave dropping southeast out of British
Columbia/western Alberta on the western periphery of the longwave
trough will bring generally light snowfall across the far northern
Rockies in northwest MT. 24 hr snow probabilities of exceeding 4
inches range between 30-50%; however during the same time  probs
of greater than 8 inches are less than 25%.  

The probability of receiving at least a tenth inch of ice is less
than 10 percent during days 1 through 3.

Hurley