Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
439 PM EDT Wed Mar 31 2021

Valid 00Z Thu Apr 01 2021 - 00Z Sun Apr 04 2021


...Central Appalachians to Northeast...
Days 1-2...
An amplifying upper trough moving east across the Great Lakes and
Ohio Valley overnight will support low pressure developing over
the northern Mid Atlantic and then tracking north into New England
by early Thursday.  Rain changing to snow is likely overnight and
then continuing into Thursday from the central Appalachians
northward into northern New England.  Compared to previous runs,
the consensus of the 12Z guidance is weaker and more progressive
with the system -- with a low track farther east and less QPF
within the cold air.  That said, probabilities for storm total
snowfall accumulations of 4-inches or more have dropped off
significantly with the latest run.  Probabilities for portions of
the northern tier of Pennsylvania into the Finger Lakes Region, as
well as the Tug Hill, Adirondacks and northern Vermont all remain
above 50 percent, but are considerably lower across much of the
region.  High probabilities for accumulations of 8-inches or more
are now largely confined to small portions of the northern
Adirondacks and the northern Green Mountains.  One area where
4-inch probabilities have increased slightly is along the West
Virginia Allegheny Mountains, where a period of northwest flow
Wednesday night through Thursday may encourage some locally
heavier totals.  Meanwhile east of the heavier snow, a wintry mix
is expected across portions of northern and eastern Maine.  While
widespread significant icing is not expected, WPC PWPF shows some
low-end probabilities for ice accumulations of 0.10-0.25 inch
centered over central and southern Aroostook County.

Pereira