Subj : HVYSNOW: Probabilistic He
To   : All
From : Dumas Walker
Date : Sun Feb 15 2026 09:00:48

FOUS11 KWBC 150732
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
232 AM EST Sun Feb 15 2026

Valid 12Z Sun Feb 15 2026 - 12Z Wed Feb 18 2026

....Cascades & Olympics... Days 2-3...

On Monday, a strengthening 500mb closed-low west of British
Columbia will slide south and just off the coast through Tuesday.
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 Cascades. Snow
levels will plummet to as low as 800ft around the WA Cascades and
Olympics, while 2000ft snow levels in the OR Cascades will be more
common. In fact, some of OR's coastal range could see snow to
elevations as low as 1,000ft. While these snow levels are getting
quite low, snowfall totals below 2,000ft in the WA/OR Cascades will
remain light. The heaviest snowfall will reside above 3,000ft
where 72-hour WPC probabilities remain in the moderate range
(40-60%) for additional snowfall totals >4" for both Snoqualmie
Pass and Stevens Pass. 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%). Impacts are most likely to be a
combination of snow covered roads and reduced visibilities.

....California... Days 2-3...

....Multiple days of heavy and disruptive snowfall to affect the
California mountain ranges beginning Sunday and continuing into next week...

A pair of potent Pacific storm systems will work together to direct
copious amounts of moisture at the mountain ranges of the "Golden
State" beginning today and lasting into the middle of the upcoming
week. A broad positively-tilted upper level troughing pattern off
the Pacific NW coast will supply low-mid level moisture that
allows for light snow through tonight into the higher terrain of
the Siskiyou, Shasta, and Salmon Mountains. The heaviest snowfall
through Sunday are likely to reside above 5,000ft where 1-2 feet of
new snow accumulation are possible at the higher elevations
through Sunday night.

By Sunday night, the upper low approaches, causing mid-to-upper
level heights to fall over CA and the strengthening IVT to direct
subtropical moisture at the state. The state will be placed ahead
of a 500mb jet streak that will generate excellent upper- level
divergence aloft, along with a barrage of Pacific moisture and
strong topographically-enhanced snowfall rates. Monday marks the
beginning of heavy snowfall along the Sierra Nevada with snow
levels initially starting out around 6,000ft from north to south
initially, then falling to as low as 3,000ft by Monday night.
Farther north, snow level will dip below 3,000ft across northern CA
as the other potent Pacific trough approaches from the northwest.
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.

By Tuesday, another round of heavy snow is expected across just
about all of the CA mountain ranges as a second, strong upper
level low dives south along the West Coast, enhancing onshore flow
and supplying additional moisture 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),
around 2,500ft in the Sierra Nevada, and just below 5,000 ft into
the Transverse Ranges with snow continuing to fall across the
state's mountain ranges into Wednesday.

California's mountain ranges welcome the snow, although it will
come down fast and furious both Monday and Tuesday. Through the
end of this discussion's timeframe (12Z Wed), multiple feet of
snow will have fallen above 5,000ft along the Sierra Nevada. WPC
probabilities show high chances (>70%) for >30" of snow having
fallen along the I-80 pass by 12Z Wednesday 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 6,000ft, although some Extreme impacts as low as 5,000ft 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). Note that there are also Minor to
locally Moderate Impacts 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 today and into the upcoming
week. With a lack of a frigid airmass ahead of this healthy
moisture source, snow will largely be confined to many of the
taller mountain peaks that sorely need beneficial snowpack. The
heaviest snowfall will reside in the Bitterroots, the Lewis Range,
Sawtooth, and the Blue Mountains where  Farther south, most
accumulations in the Great Basin, the Wasatch, Uinta, Mogollon Rim,
and CO/NM Rockies will be on the lighter side. The peaks around
Zion Nat'l Park on north along the Wasatch sport moderate-to-high
chances (50-70%) for snowfall totals >4". Otherwise, most mountain
ranges are likely to see 1-4" of snowfall through Monday.

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 footprint of Pacific moisture to track through the Rockies.
Snow levels will lower to the valley floors in western Mt and
northern ID, with some light snow possible even in the Salt Lake
City area. 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, and Wind River seeing
locally heavy snowfall along their peaks. Many of the CO ROckies
will also receive snowfall, but the heavier amounts >8" will be
confined to elevations above 9,000ft.

72-hour WPC probabilities show high chances (>70%) for snowfall
totals >8" for most of the Intermountain West's ranges, but the
locally heavier total's (>12") are most likely to occur in the
peaks of the Lewis Range, the Bitterroots, Sawtooth, Blue, Bear
River, Wasatch, and Uinta.

....Upper Midwest & Great Lakes... Day 3...

By 12Z Tuesday, the remnant yet vigorous trough that was originally
over southern CA late Monday will race across the Rockies and
project excellent 500mb PVA over the northern High Plains. The
ECMWF SATs shows a roaring 150kt 200mb jet streak (wind speeds
topping the 99.5 climatological percentile) over the Southwest will
place its divergent left-exit region over the Great Plains. With
the aid of lee-side downsloping and low-level WAA across the
Plains, an exceptionally deep surface low will form over southern
MT that reaches as low as 980mb Tuesday morning, or MSLP values
that are below the 1st climatological percentile. As WAA ahead of
the warm front reaches across the Upper Midwest, strong isentropic
ascent will ensue as the warm/moist air runs into a colder/drier
air-mass over northern ND and northern MN. Precipitation initially
starting as rain Tuesday afternoon will changeover to snow over
northeast MT, northern ND, and as far east as the MN Arrowhead
Tuesday night. Meanwhile, from northern MN and northern WI to the
northern tier of Michigan's Mitten, the overrunning setup would
favor a wintry mix of sleet and freezing rain Tuesday night and
into Wednesday morning. WPC probabilities show low chances (10-30%)
for pockets of over one-tenth of an inch of ice accretion in parts
of northern WI and MI.

There remains a high degree of uncertainty in the storm track, as
well as when the transition to snow would occur. Snow beneath the
strengthening TROWAL over northeast MT and northern ND would
perhaps not only support heavy snow, but the impressive strength of
the cyclone itself would foster blowing snow on its northern and
western flanks.In terms of snowfall, the MN Arrowhead sports low-
to-moderate chances (30-50%) for >4" of snowfall through 12Z Wed.
Most of far northeast MT, northern ND, and northern MN have
moderate chances (40-60%) for >2" of snowfall, but this is an area
where any minor change in duration or placement in the deformation
axis could result in notable changes to the snowfall forecast.
Regardless, the pressure gradient will be tight enough to where all
of these areas have moderate chances (40-60%) for Minor Impacts
(per WSSI-P) due to some combination of snowfall amounts of blowing
snow through early Wednesday morning.

....Northeast... Day 1...

The airmass in the northern Mid-Atlantic and latest guidance
continues to favor areas farther north from southeast PA across
the Delaware River and into NJ and as far east as Long Island for
light snowfall. WPC probabilities show low-to moderate chances
(30-50%) for snowfall totals >1" from the Delaware and Lehigh
Valleys on east to Long Island, but probabilities for >2" of
snowfall are <30%, indicating that most totals are minor and
likely to range between a coating-2" from southeast PA (with
elevation) on east through northern NJ and across the NYC metro.
Snow should peak in intensity Sunday night and conclude by Monday morning.

Mullinax
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