Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
406 AM EST Tue Nov 12 2019

Valid 12Z Tue Nov 12 2019 - 12Z Fri Nov 15 2019


...Great Lakes...
Days 1-2...
Persistent CAA Tuesday will drive a continuation of LES in the
favorable N/NW snow belts of the U.P. of MI, as well as the NW and
W shores of the L.P, and even towards the Saginaw Bay. While the
forcing for LES will gradually become less ideal and wane through
tonight, WPC probabilities indicate a moderate risk for an
additional 4-6", with isolated amounts to 10" possible where any
bands persist.

On day 2, Wednesday, the flow flips and becomes SW ahead of a
trough of low pressure /clipper/ digging southward from the
Plains. The airmass remains cold enough that despite WAA, LES will
re-develop but this time along the favored SW snow belts on the
western shores of the L.P. of MI and into the eastern U.P.
Snowfall should not be as significant in most places as the past
few days due to lower SLRs and overall weaker forcing, but in the
most favorable band which should setup along Lake Michigan into
the eastern U.P., WPC probabilities indicate a high chance for 6
inches, with isolated much higher amounts possible.

...Northeast...
Day 1...
Low pressure departing to the northeast and into Canada will leave
lingering snow across the mountains of NH/VT and into northern ME.
Lingering snowfall NW of the surface track will produce modest
snowfall accumulation due to moderate mid-level frontogenesis. WPC
probabilities are high for 4 inches only in extreme northern ME.
South of this, the coastal front will gradually lift northward
turning ongoing freezing rain to rain. However, WPC probabilities
indicate a low risk for 0.1" of ice accretion across portions of
ME, mostly just away from the coast, before precipitation winds
down later on day 1.

Some wrap around Lake effect and upslope snows will continue
through tonight off Lake Erie and Ontario, and into the Central
Appalachians. WPC probabilities are low for 2 inches in the
terrain, but slightly higher downwind of the Lakes.

On Day 3, the risk for significant ice and/or snow is less than 10
percent.


Weiss