Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
256 AM EST Sat Jan 22 2022

Valid 12Z Sat Jan 22 2022 - 12Z Tue Jan 25 2022

...Southwestern U.S...
Days 1-2...

Deep closed low over southern Arizona crossing into northwestern
Mexico will gradually turn east tomorrow and slowly weaken into
far west Texas by the end of Day 2 (12Z Mon). Limited moisture
will be enhanced by upslope/convergent flow into the Mogollon Rim
to produce a few inches of snow over the higher peaks with some
areas seeing over 4 inches.

...Upper Midwest/Great Lakes...
Days 1-3...

Broad cyclonic flow will become a dominant feature over eastern
Canada/CONUS through the next few days with several quickly-moving
clipper systems moving through the flow. The first two  will bring
a swath of 1-3" of snow across the Upper Midwest/Great
Lakes/Midwest to the central Appalachians with lake effect snow
across much of Michigan as well as off Lakes Erie/Ontario, albeit
briefly. The combination of modest lift/forcing and the cold
airmass supporting SLRs in the 15-20:1 range will support a fluffy
snow but with isolated areas maximizing around 4 inches closer to
the surface low track. Downwind of the Great Lakes, favored snow
belt regions in the Tug Hill and over southwestern NYS will see
enhanced snow totals over six inches while areas in the U.P. of
Michigan and eastern Lower Peninsula may see totals closer to a
foot in some areas.

...Montana into Wyoming...
Day 3...

Shortwave diving southeastward out of western Canada will tap
limited moisture over the northern Rockies day 3, enhanced by some
upslope flow as a cold front approaches from the north/northeast.
Accumulations should generally be light (under an inch or two) but
some higher elevations and north-facing slopes could see several
inches. There, WPC probabilities of at least 4 inches is moderate
(40-70%).


Fracasso