FOUS11 KWBC 050659
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
259 AM EDT Sun Apr 5 2026

Valid 12Z Sun Apr 05 2026 - 12Z Wed Apr 08 2026

...Northern New England... Day 1...

Scattered precipitation across northern New England early this
morning will become more widespread through this afternoon as a
warm front lifts northward towards the region ahead of a system
approaching from the Great Lakes. Moisture will continue spreading
northward from the Gulf and ascent isentropically atop the warm
front, expanding the precipitation shield but also driving a warm
nose >0C northward as Canadian high pressure retreats. The timing
of the heaviest wintry precipitation is likely prior to
18Z/Sunday, during which time a mixture of snow, sleet, and
freezing rain will occur before transitioning to all rain. Total
accumulations of any wintry precipitation are expected to be
modest, but still produce impacts to travel as reflected by 20-40%
chance for moderate impacts in the WSSI-P, focused over the higher
terrain of NH and ME. Freezing rain is likely to produce the most
impacts as at least a glaze of ice is possible for the higher
terrain of northern New England. However, significant icing
exceeding 0.1" is expected to be confined to just the higher
terrain of NH and ME.

Following the cold frontal passage this evening, strengthening CAA
along with modest height falls and steepening lapse rates will
allow for upslope snow showers and snow squalls from the
Adirondacks through northern VT/NH/ME into Monday.

...Great Lakes... Days 1-3...

A fast moving and compact shortwave diving out of Manitoba will
race southeast and cross the western Great Lakes Monday before
becoming embedded in the broad cyclonic flow across the Northeast
on Tuesday. This shortwave will help develop a weak wave of low
pressure along an inverted surface trough tracking southeast across
Michigan Monday. Any warm advection snowfall may stay just north
of the region, but sufficient cold advection behind this wave will
drop 850mb temps down to below -15C, sufficient for late season
lake effect snow (LES) and diurnal snow shower activity as lapse
rates steepen atop the slowly warming Great Lakes. Heavy snow is
likely to develop within this CAA south of Lake Superior,
especially along the western U.P. of MI, and downwind of Lake Erie
along the shores of western New York. Here, WPC probabilities for
4+ inches are 40-60% in the MI U.P. for Days 1-2 and 50-80% in far
western NY Days 2-3.

Snell/Weiss
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