Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
316 AM EST Thu Feb 10 2022

Valid 12Z Thu Feb 10 2022 - 12Z Sun Feb 13 2022

...Great Lakes...
Days 1-2...

Digging shortwave trough within the large scale trough over the
northern tier and Great Lakes swings through the Upper Midwest
late tonight through Friday. Warm advection ahead of the system
will bring widespread snow of a few inches followed by lake effect
snows in its wake across the western Great Lakes for day 2. The
bulk of the accumulations are expected to be under 4 inches but
the latest WPC probabilities for 4 inches or more are confined to
the favored lake effect areas off Lake Superior and
western/northwest Lower Peninsula of Michigan. Combined day 1-3
totals are likely to exceed 6 inches off Lake Superior and Lake
Ontario over the Tug Hill region.


...Northern Rockies/High Plains...
Day 2...
Southwest side of the upper trough over the Great Lakes will
support some light snow along/east of the Divide for day 2 near
the tail-end of a couple cold fronts as mid-level shortwaves
sprint through the area. SD Black Hills have the highest chance
for more appreciable snow day 2 (perhaps 4-6 inches or more) but
only a few inches are expected over higher elevations of MT/WY/CO.


...Mid-Atlantic/Northeast...
Day 3...
Digging 500 mb shortwave trough through the Southeast U.S. late
Saturday and strengthening 250 mb jet streak over the Mid-Atlantic
and Northeast may lead to low pressure development near or
slightly off the Carolina coast by early Sunday morning. The
associated forcing for ascent would bring precipitation back
across the interior regions of the Mid-Atlantic and across the
southern to central Appalachians, within the cold sector that is
marginally supportive of snow. However, this setup has a lot of
uncertainties in the latest model guidance with respect to
potential phasing of the northern and southern stream energy. The
GFS continues to be the wetter/stronger and more phased solution
with a low track along the coast that would favor higher potential
for accumulating snow across portions of western NC into Virginia.
Meanwhile, the ECMWF continues to be a less phased, weaker
solution with a shorter period of light precipitation Sunday. For
now, the WPC deterministic snow through 12Z Sunday will favor a
consensus approach and the latest WPC probabilities for 2 inches
or more on day 3 are slight to moderate across the central
Appalachians in the favored terrain areas.

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

Taylor