Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
404 AM EST Wed Nov 25 2020

Valid 12Z Wed Nov 25 2020 - 12Z Sat Nov 28 2020


...Pacific Northwest/Northern Rockies...
A series of shortwaves dropping south from Southeast
Alaska/British Columbia will continue to move through the base of
the longer wave trough moving across the Pacific Northwest this
morning.  This will support additional showers with periods of
heavy snow possible across the Washington and Oregon Cascades. 

Heaviest snow accumulations are most likely along the Oregon
Cascades where the strongest onshore flow will be focused.  WPC
PWPF indicates widespread potential for an additional 6-8 inches,
with locally heavier accumulations possible across the region on
Wednesday.

While some areas in the higher terrain could see several inches,
generally lighter amounts are expected farther east as a leading
cold front pushes into the northern Rockies today.  Areas impacted
are likely to include the northern Idaho, western Montana and
western Wyoming ranges.

...Northern New England...
A shortwave trough moving east from the Upper Great Lakes along
with low level warm advection will support precipitation moving
east across Upstate New York into northern New England on
Wednesday.  Models show cold air remaining in place to support
accumulating snow, with at least a few inches possible across
northern Maine.

For Days 1-3, the probability of significant icing (0.25 inch or
greater) is less than 10 percent.

Pereira