Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
304 AM EST Sat Feb 12 2022

Valid 12Z Sat Feb 12 2022 - 12Z Tue Feb 15 2022


...Great Lakes...
Days 1-3
Persistent upper troughing over the Great Lakes with embedded
shortwaves moving through the flow will provide several periods of
lake effect snow through Sunday night. The expected flow regime
favors the most accumulation off Lake Superior and Lake Michigan
across southwest Michigan where combined day 1-2 totals could
reach locally 4-6 inches. For the Erie and Ontario snow belt
areas, light amounts generally under a few inches are expected
over the course of the next 3 days.

...Mid-Atlantic/Northeast...
Days 1-2...
Intensifying upper jet along the East Coast and approaching
shortwave energy from the west will work with a frontal boundary
along the Carolina coast to produce widespread precipitation
across portions of the central Appalachians to Mid-Atlantic and
eventually the Northeast late tonight through Sunday morning.
Driven mostly by mid-level frontogenesis, a stripe of heavier
precipitation is expected across western VA along the I-81
corridor and then up through portions of the I-95 corridor where
the latest guidance including the hi-res models have shown an
uptick in QPF. This supports some potential for locally heavy snow
across west-central VA where the latest WPC probabilities for 4
inches or more are now moderate (40-60 percent). Some higher end
localized totals greater than 6 inches will be possible. For the
I-95 corridor from northern VA through the Northeast, the latest
WPC probabilities show slight to near moderate probabilities for 2
inches.


...Northwest...
Day 3...
Closed upper low and associated surface front quickly drops
through the Pacific Northwest late Sunday into Monday downstream
of a building northeast Pacific upper ridge and
anticyclonically-curved 150kt jet. Modest lift and forcing will
support several inches of snow to the high elevations of the
Cascades of WA/OR followed by a few inches across central Idaho
and western Montana.

For Days 1-3, the probability of significant icing is less than 10
percent.


Taylor