Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
439 PM EDT Tue Mar 30 2021

Valid 00Z Wed Mar 31 2021 - 00Z Sat Apr 03 2021

...Northeast...
Days 2-3...
There remains a strong model signal for a late-season winter
storm, with significant snow accumulations likely across portions
of the interior Northeast Wednesday night and Thursday. 

A broad scale trough moving across the Great Lakes and Ohio Valley
is expected to amplify late Wednesday as a well-defined shortwave
moves through the base of the trough.  This will drive a
negative-tilt trough lifting northeast, with a closed low
developing near Lake Ontario on Thursday.  This will support an
intensifying surface low tracking north from the coastal
Mid-Atlantic to New England late Wednesday and Thursday.  Strong
dynamics will support rain changing to snow west of the low track,
with low-to-mid level frontogenesis expected to help contribute to
a period of heavy snow.  Synoptically-driven snow, followed by a
brief period of lake-effect is expected to help bolster storm
totals east and south of Lake Ontario.  Storm total accumulations
of 4-inches or more are likely from the Northern Tier of
Pennsylvania to northern Vermont.  This includes much of the
Finger Lakes region, as well as the Adirondacks.  Locally heavier
amounts are likely within this region, especially across the
eastern Finger Lakes, as well as the Adirondack and North Country
regions, where WPC PWPF indicates greater than 50 percent
probabilities for accumulations of 8-inches or more. 

For Days 1-3, the probability of significant icing (0.25 inch or
more) is less than 10 percent. 

Pereira