Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
148 PM EST Sat Feb 05 2022

Valid 00Z Sun Feb 06 2022 - 00Z Wed Feb 09 2022

...Northern Minnesota and Northern Great Lakes...
Day 1...

An Alberta Clipper will continue to shift east across northern MN
and into Ontario tonight, with leading WAA spreading moderate to
heavy snowfall to the northeast. This system is fast moving and is
accompanied by only modest ascent, so in general snowfall
accumulations are expected to be light. However, southerly flow
aligned with Lake Michigan will likely drive some enhanced
snowfall in the form of LES north of the lake into the eastern
U.P. Here, snowfall rates may exceed 1"/hr, and WPC probabilities
for 6" are as high as 30% between Manistique and Mackinaw City.


...Northeast and New England...
Day 3...

A shortwave dropping out of Saskatchewan Monday night will shift
into the Ohio Valley and amplify on Tuesday. Downstream of this
impulse, upper level jet streaks are progged to increasingly
couple, with the result being surface cyclogenesis off the east
coast. Guidance today has trended to be more consolidated with the
low leading to a track that is NW of the previous cycle. The
exception to this is the GFS which has been consistent and
actually shifted a bit east with today's 12Z run. With a lot of
spread remaining in the ensemble clusters, confidence in the
evolution of this system is low. However, pronounced WAA should
spread precipitation onshore New England Monday night and Tuesday,
resulting in at least moderate snow inland, with a rain/snow mix
likely along the coast. The WSE and NBM median are well aligned
with amounts, although the WSE is a bit SE of the NBM with its
maximum axis. To account for the GFS/GEFS, the farther SE heavy
snow axis is currently preferred, but a lot of wobbling can still
be expected with future runs. At this time, WPC probabilities are
moderate to high for 4+ inches from the White Mountains of NH
eastward across central and northern Maine, with local amounts
above 8 inches possible. Lighter snows accumulating to 2 inches or
more are possible across much of VT and MA, but this could still
change quite a bit in the next few model cycles.

Additionally, some very light icing is possible across the
Tri-State area of NJ/NY/CT and southern CT/RI Monday night as
precipitation spreads northward into sub-freezing temperatures,
but the DGZ remains dry. WPC probabilities for 0.01" are only
about 5-10%.


The probability of significant icing is less than 10 percent.

Weiss