FOUS11 KWBC 140755
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
355 AM EDT Tue Apr 14 2026

Valid 12Z Tue Apr 14 2026 - 12Z Fri Apr 17 2026

...CO Rockies... Day 1...

Upper low over southwestern UT this morning will move eastward and
weaken slightly into a strong trough as it enters the CO Rockies
this evening. SW flow will help bring in some moisture to the
region which will wring out light to moderate snow over the
Rockies. Snow levels will be around 7500-8000ft, so any significant
accumulations of at least 6 inches are >50% above about 10,000ft.

...Pacific Northwest through the Northern Rockies... Days 1-3...

Active wintry pattern from the Pacific Northwest through the
Northern Rockies starts today. A strong upper low moving
southeastward along the BC coast will dive into western WA tomorrow
evening and past the Divide Thursday evening. The upper low will
split into two pieces -- the northern portion will continue
eastward as a weakly closed upper low while the southern portion
will sink farther south into the Great Basin. Though moisture will
be rather limited (just a narrow surge of moisture ahead of the
cold front), heights and mid/lower-level temperatures will be well
below average and below the 1st percentile for this time of year,
reminiscent of a mid-winter system.

Rain and mountain snow will precede the cold front today with
initial snow levels around 3500-5000ft along the Cascades and
5000-6000ft over the Northern Rockies. Snow will increase later
this afternoon and tonight via upslope enhancement with rates of
1-3"/hr possible in the higher elevations, generally above the
passes. Cold front should push through the WA Cascades early
Wednesday which will push the heavier snow rates southward to stay
just ahead of the front into the OR Cascades. Snow levels will fall
to around 1000-1500ft tomorrow morning behind the front as snow
lightens. However, the upper low will then swing through with its
cold core and additional snow to around 1500-2000ft during the
afternoon hours. To the east, snow will increase over the Northern
Rockies where the cold front will take nearly a day longer to reach
past the Divide. There, too, snow levels will fall sharply behind
the front down to below 2000ft (i.e, all valley floors) where at
least some accumulation is probable. On Thursday
afternoon/overnight, the upper low will move through the Northern
Rockies with additional light to moderate snow mainly over SW MT
southward. Through 12Z Friday, with the strongest height falls over
northern UT into WY, snow will be favored over the northern
Wasatch/Unitas but especially into Wyoming (Bighorns) as it ends
over the Pacific Northwest.

WPC probabilities for at least 6 inches of snow are >50% above
about 2000-3000ft in the Cascades, 4000ft in the Northern Rockies,
and 7000ft in Wyoming. For at least a foot of snow, WPC
probabilities are >50% above about 3000-4000ft in the Cascades
(this includes Snoqualmie Pass), 5000-6500ft in the Northern
Rockies, and 9000-10,000ft in Wyoming. Total accumulations may
range from 1-3ft in the region, along with windy conditions, making
for very difficult to impossible travel through the terrain.

Additionally, the combination of the sharp cold front and well
below normal mid-level temperatures could yield some snow squalls
or at least some convective snow along/ahead of the front Thursday,
despite it being April (outside the more typical period). This
could cause short-lived but impactful drops in visibility and
hazardous travel.

The probability of significant icing for days 1-3 across the CONUS
is less than 10 percent.

Fracasso

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