Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
237 AM EDT Sat Nov 2 2024

Valid 12Z Sat Nov 02 2024 - 12Z Tue Nov 05 2024

...Mountainous West...
Days 1-3...

An active pattern remains for much of the West this period,
downstream of a strong upper ridge between Alaska and Hawaii. This
will take a series of systems on a NW to SE path from the PacNW
through the Great Basin and into the Rockies this weekend into
early next week. For day 1, ongoing system in the NW will continue
to bring snow to the Cascades eastward to the northern Rockies and
southward through the Bitterroots, Tetons, Wind River, into the
Wasatch. WPC probabilities for at least 8 inches of snow are >50%
above 5000ft or so in the NW to about 9000ft over the Uintas.

On day 2, the trough will dig into the Four Corners region and
support light to modest snow for the CO Rockies, especially above
10,000ft where WPC probabilities for at least 8 inches of snow are
>50%. Light snow is probable into the I-25 corridor but amounts are
quite uncertain. Accumulating snow is favored farther south into
the Palmer Divide. By day 3, that upper trough will continue to
move slowly through NM with a focus for snowfall over the Sangre de
Cristos into the Raton Mesa. There, WPC probabilities for at least
8 inches of snow are moderate (40-70%). Back to the PacNW, the
next system will move ashore with another surge in moisture to the
area and significant snow for the WA Cascades. Snow levels will
rise to 4500ft or so with a decent moisture plume (300-400 kg-m/s
IVT) then fall behind the front. Higher mountains passes will
likely be affected with significant accumulations, but lowering
snow levels will likely affect some lower passes as well. WPC
probabilities for at least 8 inches of snow are >50% above
3000-3500ft or so.


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

Fracasso