FOUS11 KWBC 160801
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
301 AM EST Mon Feb 16 2026

Valid 12Z Mon Feb 16 2026 - 12Z Thu Feb 19 2026

...Pacific Northwest... Days 1-3...

A strengthening 500mb trough will dig south down the British
Columbia coast towards Washington State. The trough will quickly
close off into a closed low west of British Columbia Monday night
into Tuesday with 500mb heights below the 0.5 climatological
percentile. The low will drift east over the Columbia River Valley
Tuesday evening and open up into a trough early Wednesday morning.
Then as that low exits to the east, one more shortwave trough over
coastal British Columbia heads for the Olympic Peninsula Wednesday
night. With this very complex, rapidly changing, but slow-moving
upper level pattern evolution, a prolonged period of active weather
is expected over the Pacific Northwest.

Sharp height falls and excellent 500mb PVA, combined with an
influx of 850-300mb mean-layer moisture and upslope enhancement,
will produce periods of snow over the Olympics and WA/OR Cascades
through mid-week. Snow levels will plummet to as low as 500ft
around the WA Cascades and Olympics Monday night and into Tuesday
morning, while 2,000ft snow levels in the OR Cascades will be more
common. Some of OR's coastal range could see snow down to
elevations as low as 1,000ft on Tuesday, and even some very light
snow possible along I-5 from the Tacoma/Olympia area on south
through the Willamette Valley. The heaviest snowfall is expected
above 2,000ft where 72-hour WPC probabilities are now into the
higher moderate range (50-70%) for additional snowfall totals >8"
for snowfall in the lower WA Cascades and most of the OR Cascades.
WPC probabilities for snowfall >4" remain in the moderate range
(40-60%) for Snoqualmie and Stevens passes. Given the long duration
but lack of heavy hourly rates, WSSI-P shows the chances for Minor
Impacts are generally on the low side (20-40%). The only exception
is the OR Cascades where there are moderate chances (40-60%) for
Moderate Impacts (hazardous travel, some closures/delays possible)
above 1,000ft. Note that the WSSI-P does show low-to-moderate
chances (20-40%) for Minor Impacts along I-5 from Olympia on south
to Eugene Monday night and into Tuesday. Impacts are most likely to
be a combination of snow covered roads and reduced visibilities.

...California... Days 1-3...

...Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges this week...

A pair of potent Pacific storm systems are working together to
direct copious amounts of moisture at the mountain ranges of the
"Golden State". While heavy snow has been unfolding in the
Siskiyou, Shasta, Trinity, and Salmons mountains of northern CA
since Sunday, today marks the beginning of very heavy snowfall
along the Sierra Nevada with snow levels initially starting out
around 6,000ft, then falling to as low as 3,000ft by Monday night
in the northern Sierra, and 4,000 ft for the southern Sierra
Nevada. Snowfall rates between 1-2"/hr will be common with some
instances of >3"/hr snowfall rates in the central and southern
Sierra Nevada. Heavy snow is also expected in the Transverse Ranges
above 6,000ft.

On Tuesday, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second, arguably stronger
upper level low dives south along the West Coast, closely following
the first. This will spike onshore flow and additional moisture
supply on the southern and eastern flanks of the upper low. Snow
levels will fall to around 1,000 ft in far northern California
(including the northern coastal range) Tuesday night, around
2,500ft in the Sierra Nevada, and just below 5,000 ft into the
Transverse Ranges. Snow will continue to fall across California's
mountain ranges trough Wednesday as yet another 500mb shortwave
trough west of WA continues to sustain what feels like an endless
supply of Pacific moisture into the Golden State. With the longwave
trough overhead, snow levels could creep down as low as 1,000ft in
central CA and may support minor accumulations down to 1,000ft.

California's mountain ranges welcome the snow, although it will
come down fast and furious through mid-week. Through the end of
this discussion's timeframe (12Z Thu), snowfall will be measured
in feet above 4,000ft along the Sierra Nevada. WPC probabilities
show high chances (>90%) for >30" of snow along Donner Pass
through 12Z Thursday and more snow still to come. The WSSI shows a
large swath of Extreme Impacts (Substantial disruptions to daily
life; extremely dangerous travel or impossible driving conditions,
extensive closures) for elevations generally above 5,000ft,
although some Major impacts as low as 4,000ft are possible. Major
to locally Extreme impacts are showing up in the peaks of the San
Gabriel and San Bernadino mountains, with mostly Moderate-to-Major
Impacts (increasingly more disruptive to travel jumping from
Moderate to Major). There are also likely to be some Major impacts
in the Coastal Range of northwest CA above 2,000ft. Note that
there are Minor to locally Moderate Impacts expected along I-5
around Mount Shasta, signifying potential travel delays for I-5 in
the more elevated terrain of northern CA.

...Intermountain West... Days 1-3...

Pacific moisture ahead of the longwave upper trough off the West
Coast will spill over the Cascades and Sierra Nevada and reach many
ranges across the Intermountain West this week that badly need the
boost in snowpack. With a lack of a frigid airmass ahead of this
healthy moisture source, the bulk of the heavy snow will be largely
confined to many of the taller mountain peaks that sorely need
beneficial snowpack. The heaviest snowfall on Monday will reside
in the Blue, Sawtooth, Wind River, Uinta, and as far south as Mt.
Charleston and the Mogollon Rim. WPC probabilities are high (>70%)
for snowfall totals >6" in these mountain ranges through Monday night.

On Tuesday, the highly anomalous upper-low off the Pacific NW coast
will help to usher the initial upper low over southern CA east into
the Intermountain West, causing widespread height falls and a
larger plume of Pacific moisture to pass over the Rockies. The
potent closed low off the Pacific NW coast on Tuesday then heads
inland over the interior NW and northern Rockies on Wednesday,
prompting snow levels to crash and most valleys (except the
eastern WA Columbia River Basin) are likely to see at least a
coating of snow. Still, the lack of a frigid airmass at the surface
will keep the bulk of the heavy snow in the mountains with ranges
such as the Wasatch, Bear River, Tetons, Uinta, Wind River,
Mogollon Rim, and CO Rockies seeing anywhere from 1-2 feet of snow.
Expect Minor to Moderate Impacts, per the WSSI, with travel over
passes from the Lewis Range and Bitterroots to as far south as the
Mogollon Rim likely to contend with hazardous travel conditions.

...Northern Plains & Upper Great Lakes... Days 2-3...

A powerful cyclone forming in the northern High Plains on Tuesday
will be the focus for heavy snow and blowing snow from northern MT,
as well as periods of snow and accumulating ice in the Upper
Midwest and Great Lakes Tuesday night. The storm system itself will
feature MSLP values in low-mid 980s over the Dakotas with blustery
winds in just about all quadrants of the storm. Beneath the TROWAL
over northeast MT and ND, hourly snowfall rates up to 1"/hr are
possible Tuesday night into Wednesday morning with wind gusts
topping 40 mph in eastern MT and western ND. Meanwhile, strong WAA
aloft overrunning a sub-freezing airmass will not only foster heavy
snow in northeast ND and northern MN, but also allow for freezing
rain to unfold from north-central MN on east through northern WI
and into northern MI. The worst of the icing is likely to occur
Tuesday night and into Wednesday morning in these areas. The
heaviest snowfall is expect to unfold in the MN Arrowhead where
lake-enhanced snowfall will play a vital role in areas receiving
over a foot of snow.

WPC probabilities feature moderate chances (40-60%) for ice
accumulations over one-tenth of an inch over the tip of Michigan's
Mitten, as well as along the southern shores of the Upper
Peninsula. In terms of snowfall, WPC probabilities show moderate-
to-high chances (50-70%) for snowfall totals >4" from northeast MT
across northern ND, northern MN, and the northern shores of the
Upper Peninsula. The MN Arrowhead sports the highest odds of
receiving over a foot of snow with WPC probabilities showing
modertae-to-high values of 50-70%. There are even some low-to-
moderate chances (20-50%) for localized amounts surpassing 18" in
the Arrowhead through Wednesday. The WSSI shows a large swath of
Minor to Moderate Impacts in these areas between Tuesday and
Wednesday, showing an extensive part of the North Central U.S.
will be subjected to hazardous travel conditions starting Tuesday
and lasting through Wednesday.

...Northeast... Day 3...

The strong low-level WAA ahead of the powerful storm system in the
Upper Midwest will stretch as far east as the Northeast on
Wednesday. High pressure over southern Canada is providing enough
cold air to support wintry precipitation, although precipitation
type will largely depend upon the depth of the sub-freezing
temperatures within the boundary layer. Guidance is coming into
decent agreement on a narrow tongue of QPF >0.5" over much of
Upstate NY and as far east as the Berkshires and Green Mountains.
However, guidance disagrees on the placement of this band of heavy
QPF. The farther south the band is, the farther away from the
source of the colder air it becomes, making a combination of snow,
freezing rain, and event potential plain rain in lower elevation
areas. However, farther north solutions would place the band of QPF
over the Adirondacks and Green Mountains, which would favor
heavier mountain snow there. Then there is the conundrum of
precipitation rates. While rates may start off heavy via strong
850mb FGEN, as the storm weakens over the Upper Midwest on
Wednesday so does the influx of WAA, leading to frontolysis aloft
that would weaken low- level forcing and reduce the dynamic cooling
aloft to support periods of heavy snow.

This is all to say that there remains a fair amount of uncertainty
in the forecast. WPC probabilities are indicating the Adirondacks,
Green, and White Mountains have low-to-moderate chances (30-50%)
for snowfall totals >4" through Wednesday night. Given the
uncertainty in the position of the heaviest QPF and lingering
questions regarding low-level thermal profiles, areas
with elevations over 1,000ft would be most favored to see some
accumulating snowfall on Wednesday. The Champlain and Upper Hudson
Valleys would likely reside just far enough north to support
measurable snowfall, as evident in WPC's probabilistic guidance
that highlights moderate chances (40-60%) for snowfall totals >1"
on Wednesday. Lastly, some minor ice accumulations are possible as
far south as the Lower Hudson Valley and southern New England with probabilities showing low-to-moderate chances (20-40%) for at least one-hundreth of and inch of ice accretion on Wednesday.

Mullinax
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