FOUS11 KWBC 142027
QPFHSD

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

Valid 00Z Wed Apr 15 2026 - 00Z Sat Apr 18 2026


...Cascades...
Days 1-2...

A low pressure system currently centered over Southeast Alaska (aka
the Alaska Panhandle) will shift SE to central WA through Wednesday
before opening into a split trough with a portion that digs down
the Rockies through Friday and one that drifts east over the
southern Canadian Prairies. Pacific moisture is somewhat limited,
but the cold aspects of the system will make it reminiscent of a
mid-winter system.

Snow levels starting around 3500ft on the WA Cascades quickly drop
to 1000ft or less late this evening as the associated strong cold
front pushes through. The heavier snow rates will stay just ahead
of the front that works its way down the OR Cascades Wednesday. A
round of more moderate snow rates arrives to the WA Cascades with
the upper low center Wednesday afternoon. Snow levels bump up to
around 1500ft through this time before Cascades snow tapers off
Wednesday night.

Day 1 snow probs for >8" are 50-90% along the Cascades above about
2500ft including Snoqualmie and Santiam Passes. Winter Storm
Warnings remain in effect through the range. Day 2 snow probs for
>4" are generally 30-50% for the central WA Cascades and
northern/central OR Cascades.


...North to Central Rockies and central High Plains...
Days 1-3...

Moisture shifts east across the Cascades through the northern
Rockies tonight through Wednesday before the plume settles over
northwest Wyoming Wednesday night into Thursday. The southern
portion of the trough drives expanding precip and a low level
upslope component to the CO Rockies and adjacent High Plains
Friday.

The cold front reaches northwest MT Wednesday morning with a
gradual progression to Wyoming through Wednesday night. Snow levels
ahead of the cold front are 5000-6000ft over MT before dropping to
2000-3000ft behind the front as rates decrease. Snow levels over WY
rise to 8000ft in the warm sector Wednesday before dropping to
3000ft Wednesday night behind the front. Snow levels around 9000ft
in CO on Thursday drop to 4000-5000ft through the day Friday.

Day 1.5 WPC snow probs for >8" are 40-80% for all western MT and
central/northern ID ranges. Day 2 snow probs for >8" are 50-80% for
the Absarokas, Tetons, and the Wind River Range. Then Day 3 probs
for >6" are 40-80% for the Bighorns, Wind River again, and southern
WY through northern CO Ranges as well as the Uinta and higher
Wasatch in UT.

As a final note, the sharp cold front should produce snow squalls
or convective snow bands along/ahead of it Wednesday and Thursday.
This activity 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.


Jackson



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