Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
432 AM EDT Mon Oct 21 2019

Valid 12Z Mon Oct 21 2019 - 12Z Thu Oct 24 2019

Days 1-3...

...Northern and Northwest sections of the U.S...

Low pressure over the north-central Plains drifts to Lake Superior
into Tuesday. Wrap around precip is producing localized snow near
the SD/NE border and will redevelop snow in the heaviest bands
tonight as it moves into northern MN. Only light snow
accumulations are expected.

A clipper system crosses British Columbia tonight and moves from
eastern MT to SD Tuesday night. South of this clipper is a plume
of deep moisture that will likely bring heavy precipitation to
western Washington and the northern Rockies, but increasing snow
levels through early Tuesday will limit the threat for widespread
heavy snow amounts. 

A shortwave trough moving into western Canada on Tuesday will
begin to drop southeast Tuesday night, bringing colder air back
into the northern Rockies Tuesday night into Wednesday.  Behind
the cold front, some locally heavy snow may develop along the
western Montana into the northwestern Wyoming ranges Tuesday night
into early Wednesday.  Meanwhile, expect a swath of light
accumulations to follow a the clipper dropping southeast across
eastern Montana into the western Dakotas.


The probability of significant icing is less than 10 percent.

Jackson