Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
327 AM EST Sun Nov 12 2023

Valid 12Z Sun Nov 12 2023 - 12Z Wed Nov 15 2023

...Pacific Northwest...
Day 1...

Another weather system will clip coastal Washington and the
Pacific Northwest later today through early Monday, with the bulk
of the forcing and moisture transport positioned into British
Columbia compared to the most recent storm system. The greater
southerly flow will act to limit the favored orographic upslope as
well as limit the overall IVT values (generally in the light to
moderate range). With snow levels rising above 4500 ft as well,
the greatest snowfall accumulations will be confined to the higher
peaks of the Olympics and northern WA Cascades where the
probabilities of at least 4 inches are 30-50%. 

...Northern California...
Day 3...

An upper level trough is likely to close off into an upper low
later Tuesday into Tuesday night, eventually carrying moisture in
the southwest flow ahead of it across portions of coastal
California by mid-week, though forecast trends show a slower
arrival of the moisture compared to recent model runs. The
southwest flow ahead of it however will result in relatively high
snow levels (>7000 ft), capping any snowfall accumulations to the
highest peaks of northern California. Through 12Z Wednesday, a few
inches may accumulate where WPC snow probabilities for at least 4
inches are 10-20%.


Taylor