FOUS11 KWBC 110909
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
509 AM EDT Wed Mar 11 2026

Valid 12Z Wed Mar 11 2026 - 12Z Sat Mar 14 2026

...Cascades Through The Northern Rockies... Days 1-3...

...Washington Cascades Blizzard into Thursday...

Active winter weather continues across the WA Cascades and northern
Rockies through Friday night with heavy precip and high winds
especially tonight.

A focused axis of 0.75 to 1" PW shifts across the western WA/OR
border through Friday night with a trough axis crossing tonight.
Powerful winds accompany the leadup to the trough axis with 850mb
winds of 40-60kt expected across the WA and northern OR Cascades
tonight before easing into the 25kt range on Thursday. Snow levels
currently in the 2000-3000ft range rise to around 5000ft this
afternoon in the WAA of the AR axis before dropping over WA into
the 2000-3000ft range late tonight as noted within the negative
temperature advection regime focused between 850-700mb. This will
be quite the snow event for the higher elevations of the WA
Cascades and the higher northern ID/northwestern MT ranges. Days
1-3 each have snow probs for >24" above 40% in the Cascades and 30%
in those ID/MT ranges (with only a little wobble in the axis south
on Day 2 before returning north for Day 3). Snow probs for >12" at
Snoqualmie Pass are 70% on Day 1, 95% on Day 2, and 70% again for
Day 3. Major impacts are expected across the WA Cascades, the
Bitterroots, western MT ranges and on Day 2 for northwestern WY ranges.

...Northern Great Lakes and Far Northeast... Day 1..

Northern stream trough over the Upper Midwest with southern stream
low over west Texas shift east to the Great Lakes/Southeast through
tonight. The surface low over northern IL rapidly develops as it
shifts across southern MI this morning and Quebec tonight. Banding
around the elongated 850mb low over WI/MI is continuing over the
U.P. with a separate area of light to moderate snow in central Neb.
This axis pivots more N-S through this morning before lifting into
Canada. Day 1 snow probs for >6" additional after 12Z are 50% in
the Huron Mtns and 20-40% in the eastern U.P. and far northern
Aroostook Co Maine.

Meanwhile WAA ahead of the low shifts across the eastern U.S. with
sufficient lingering cold over interior north- central Maine into
Coos Co NH where Day 1 ice probs for >0.1" are 40-80%. Ongoing ice
over the northern L.P. lingers this morning with 20% probs for an
additional 0.1" after 12Z in a swath of the northeastern part of the state.

...Northern Plains through Northern Great Lakes into Northeast... Days 2/3...

The potent shortwave trough axis crossing northern WA Wednesday
night on a 150kt potent WNWly jet really amplifies over the
northern Plains Thursday afternoon, producing a mature surface low
that crosses the northern Great Lakes Thursday night and pushes up
the St. Lawrence on Friday before reaching northern Maine Friday
night. A strong wind field and heavy snow bands will develop with
this low, though there remains some uncertainty with the track. The
EC-AIFS and CMC are farther south with a Day 2 QPF axis focused
just south of Duluth, while the GFS and NAM have the axis north
from Duluth. A compromised solution in between (WPC QPF actually
favors the south solution) is pretty close to the AIGEFS axis with
more magnitude. Day 2 snow probs for >6" are 40% over northern MN
with Day 2.5 probs 40-80% from the North Shore of MN, far northern
WI, and all of the U.P. and the northern L.P. This track then
continues east with Day 3 probs for >6" 40-60% over the Tug Hill
and southern Adirondacks. Unlike the previous system, this one is
much more simple with rain/snow and not a wintry mix. However, the
deep low will create quite a wind field with localized blizzard
conditions possible in spite of the North Woods' friction.


Jackson


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