FOUS11 KWBC 030719
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
219 AM EST Tue Mar 3 2026

Valid 12Z Tue Mar 03 2026 - 12Z Fri Mar 06 2026

...Mid-Atlantic to the Northeast... Days 1 & 3...

The general synoptic pattern is unchanged from the previous
forecast. Weak shortwave trajectory from the Mid Atlantic will
motion northeastward off the the coast of Southern New England
with moisture carried poleward in the process. 1041mb surface
ridge positioned off Cape Cod will lead to a shift in the low-level
flow by morning to a more easterly orientation with a nosing low-
level jet around 850mb allowing a warm air protrusion into the
boundary layer as we push through D1. Cold air will slowly retreat
northward with snow/ice across the Northeast changing to rain, even
as far north as Southern New England. Areas north of I-90 will hold
on to cold air the longest with snow/ice the primary p-types
through the event. Best ascent will be fixed to the southeast,
however, so totals for freezing rain and snow will be relatively
modest, at best leading to some minor to bordering moderate impacts
where ice accretion approaches 0.1" or greater.  Low pressure will
eventually carry the system off the coast by early Wednesday
leading to an end of the impact from this disturbance.

Snow amounts will generally be light, especially in the Northern Mid-
Atlantic. From around I-90 northward, WPC probabilities for at
least 4 inches of snow are low (10-40%) as most amounts should be
in the 1-3" range. Higher elevations of the Green and White
mountains show the highest chance for at least 4 inches of snow.
The freezing rain footprint will extend from the WV Panhandle into
the Allegheny front, northward along the I-81 corridor and as far
west as the I-79 corridor northward to about I-90 and eastward to
about I-95. Freezing rain accumulations will be highest where the
cold air holds on longest near the highest QPF, which is forecast
to be over the central Appalachians and highlands of west-central
PA. WPC probabilities for at least 0.10" icing are between 30-60% over
west-central PA up towards the NY state line with lower probs <20%
for parts of the Catskills and Berkshires.

By D3, a potent mid-level shortwave will eject east-northeast out
of the Midwest, aiming sights at Upstate NY through New England by
the end of the period. A trailing axis of confluence over Atlantic
Canada with a strong 1038+ mb surface ridge migrating east out of
Central Canada will set the stage for a stout low-level CAD
signature within the valley's of New England leading to a
heightened threat for freezing rain as the boundary layer between
925-700mb will be too warm, promoting liquid hydrometeors. Shallow
but impressive CAD will lead to a transient light to moderate
freezing rain between 00-12z Friday with WPC probabilities for
>0.1" already signaling 10-40% potential across the
Hudson/Champlain Valley's along the NY/VT border, as well as
through the southern Green mountains and neighboring Berkshires.

...Central Rockies... Day 1...

Current WV satellite and UA analysis shows a very distinct closed
upper reflection located over the southern reaches of the Tetons
with snowfall occurring over the Wasatch over into the WY ranges
and the northwestern portion of CO. This threat will carry through
the morning with snowfall likely to breach 4" across portions of
the Central Rockies including the Medicine Bow range located over
northern CO and southern WY. Probs continue to come in between
40-70% for those areas of additional snowfall >4" leading to totals
likely to push 10+" through the storms life cycle. System will
exit the second half of the forecast leading to an end to the
threat as we move into the evening hours.

...Pacific Northwest, Great Basin, and Northern Rockies... Days 2-3...

A deepening system in the Gulf of Alaska will move southeastward
through today, bringing a surge of moisture into the Pacific
Northwest ahead of a cold front. Moisture levels and IVT anomalies
will be modest, and snow levels will start around 5000-6000ft
before falling post- FROPA to around 4000ft Wednesday then to near
3000ft Thursday as precipitation becomes much lighter. Snow will
spread eastward to the Northern Rockies (northern ID to
northwestern MT) early Wednesday then to the Great Basin late
Wednesday into Thursday as the upper trough moves into southwestern
OR. Snow could be heavy at times near/above pass level as snow
levels fall across the Cascades tomorrow night. By the end of the
forecast period, the upper trough may deepen into a closed low over
southwestern UT with snow spreading into the Uintas and Wasatch as
well as western WY ranges, continuing into the medium range.

WPC probabilities for at least 8 inches of snow are highest over
the WA/OR Cascades for D2, generally above 4000-5000ft. Plowable
snow (at least a couple inches) is likely (>80% chance) around
Snoqualmie Pass. To the east, WPC probabilities for at least 8
inches of snow are >50% above 5000-6000ft or so over the Blue
Mountains, central ID ranges, western MT, UT mountains, and
northern NV.

Fracasso/Kleebauer

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