Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
316 AM EDT Wed Nov 01 2023

Valid 12Z Wed Nov 01 2023 - 12Z Sat Nov 04 2023

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

A storm system associated with an upper trough approaching the
Pacific Northwest will deliver a surge of 700mb moisture flux into
the Northern Rockies on Thursday and persist into Friday. The
conveyor belt of moisture is anomalous, as evident by NAEFS which
suggest IVTs values will top the 97.5 climatological percentile
Thursday afternoon and evening. While there is no shortage of
moisture available, there is a significant lack of sub-freezing
air throughout the region. That is why, unlike the more recent
winter storm that occurred back on Oct 24-26, this particular
setup will keep snowfall accumulations confined to the highest
elevations of the Absaroka, Tetons, and Wind River Ranges. WPC
probabilities for >4" of snowfall are peaking between 40-50% near
Yellowstone National Park, giving some confidence to having some
notable accumulations. However, probabilities for >8" are <10% at
this time. There is a slight chance some of the highest peaks
could pick up over 8" by the start of the weekend given the long
duration of available moisture and topographic enhancement due to
upslope flow. That said, the WSSI is sporting not much more than
Minor Impacts for parts of the Tetons, Absaroka, and Wind River
Ranges late Thursday into Friday.

Mullinax