Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
344 AM EST Sun Nov 05 2023

Valid 12Z Sun Nov 05 2023 - 12Z Wed Nov 08 2023

...Northwest, California through the Northern Rockies...
Days 1-3...

A series of shortwave troughs continue to produce rounds of
unsettled weather and mountain snow over the Northwest and
Intermountain West through Tuesday. 

A zonal 130+ kt upper jet persists over the OR/CA border into
Monday with several impulses/shortwave troughs pushing east and
allowing snow levels of 5000-6000ft to persist over the Pacific
Northwest, 5000-8000ft over the northern Rockies. Day 1 snow probs
are limited to the highest Cascades and northwest WY.

The strongest wave reaches the PacNW coast early Monday with
further reinforcing troughing allowing the axis to dig south
through central CA Tuesday. Enhanced moisture ahead of this
stronger wave brings a focus for heavy precip east from the OR/CA
border with Day 2 snow probs moderately high (50-80%) for >6"
along the Cascades, the northern Sierra Nevada, Salmon
River/Sawtooth ranges of ID, and western WY.

Snow levels drop to 4000-5000ft under the amplifying trough axis
over much of the Northwest Monday night and persist through
Tuesday. However, moisture gets shunted farther south with the Day
3 snow prob focus over the Cascades, Bitterroots and Northwest WY
whree there are moderate probabilities (40-70%) for an additional
>6".


Northern Plains...
Days 1 and 3...
Light icing is expected this morning on southerly flow over
northern portions of North Dakota into northwest Minnesota and
then again Tuesday morning also over northern North Dakota.
However, significant icing has a probability of less than 10%.


Jackson