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Mountain Weather Forecast

Issued: 3:00 PM PST Wednesday, February 7, 2018
by Robert Hahn

Jump to: Weather Forecast I Snow/Freezing Level I Precipitation I Free Winds 5k I Free Winds 9k I Extended Weather

Weather Synopsis for Wednesday & Thursday

On Wednesday, the Pacific Northwest continues to sit between a robust and relatively stationary high pressure off the northern coast of California and a deep low over Hudson's Bay. The jetstream lies to our north, taking today's storm track and precipitation on a higher-latitude trajectory than previously expected. The resulting weather has been warmer than anticipated for Wednesday, with relatively drier weather. Winds have been and will continue to be moderate to strong on the east slopes of the Cascades at higher elevation and downslope winds to the east of the Cascades have scoured out the cold pool that normally resides there. Mazama saw an 18F jump in temperature in just one hour this morning due to a wind shift from E to W and temperatures are now in the mid-50's. Winds below crest-level have been light to moderate.

To the west of the Cascade crest the atmosphere has been very stable on Wednesday morning, meaning that the temperature doesn't decrease significantly with height as you normally expect. Temperatures are in the low-to-mid 30's at most NWAC stations, including Camp Muir!

Light precipitation is beginning to re-develop in the Northwest Cascades this afternoon with light amounts expected. Some locations in the central and north Cascades (west slopes) have also experienced freezing rain above 5000 feet or drizzle. 

As a system approaches from the W-NW tonight, W-SW winds will increase to the moderate-to-strong range by morning at crest level and snow levels will begin lowing slightly as the jetstream drops southward, pushing the ridge back south. In some cases east of the Cascade crest, winds will be very strong tonight.

On Thurday, the reasonably strong, but relatively moisture-starved surface cold front associated with a short-wave trough will cross the Pacific Northwest, arriving in the Olympics in the early morning, then the NW Cascades around 10 AM and reaching Mt. Hood during the evening hours.

Snow levels will drop significantly behind the front with rain changing back to snow at many mid-elevation locations between 1-4PM at the Mt. Baker base and between 4 and 7 PM for Stevens Pass and Crystal Base, with a changeover at Snoqualmie pass level likely after 7 PM. Most precipitation will be with moderate post-frontal showers behind the cold front and a potentially strong convergence zone that is likely to set up in the Stevens Pass vicinity during the afternoon and early evening hours.

Some lighter convergence will focus lingering snowfall in the Snoqualmie Pass vicinity on Thursday night.

Weather Forecast

Olympics
Wednesday Partly cloudy with filtered sunlight. Moderate ridgetop westerly winds.
Wednesday Night Fair with partly cloudy skies. Moderate ridgetop W-SW winds increasing to strong at times.
Thursday Mostly cloudy, becoming partly cloudy in the afternoon. Strong ridgetop W-SW winds.
Becoming mostly clear. Moderate ridgetop westerly winds.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Wednesday Cloudy central to north Cascades with some light rain or drizzle. Sunny south Cascades. Moderate crest-level westerly winds.
Wednesday Night Mostly high clouds. Crest-level winds becoming moderate to strong.
Thursday Mostly cloudy in the morning from Snoqualmie Pass northward, becoming partly cloudy in the afternoon. Expect filtered sunlight further south in the morning with low clouds moving in during the afternoon. Moderate to strong W-SW crest-level winds.
Mostly cloudy with westerly winds decreasing.
East Slopes of the Washington Cascades
Wednesday Cloudy central to north Cascades near the crest with some light rain or drizzle possible. Sunny south Cascades and east of the crest with warm temperatures replacing the typical mid-winter cold pool. Moderate crest-level westerly winds. Moderate to strong crest-level westerly winds.
Wednesday Night Mostly high clouds. Crest-level winds becoming moderate to strong.
Thursday Mostly cloudy in the morning from Snoqualmie Pass northward, becoming partly cloudy in the afternoon. Expect filtered sunlight further south. Moderate to strong W-SW crest-level winds.
Becoming partly to mostly clear with westerly winds decreasing.
Mt. Hood
Wednesday Low clouds dissipating early, then increasing high clouds.
Wednesday Night High clouds.
Thursday Increasing clouds in the afternoon.
Mostly cloudy.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Wednesday Afternoon Snow Level 8000' 6500' 6500' None' None' 7500' None' 9500'
Wednesday Night Snow Level 6500' 5000' 5500' None' None' 6500' None' 9000'
Thursday Morning Snow Level 5000' 4000' 4000' None' None' 4500' None' 8500'
Thursday Afternoon Snow Level 3500' 4000' 4500' None' None' 4000' None' 8500'
Hurricane Ridge Elevation
Wednesday Afternoon Snow Level
8000'
Wednesday Night Snow Level
6500'
Thursday Morning Snow Level
5000'
Thursday Afternoon Snow Level
3500'
Thursday Night Snow Level
2500'
Mt. Baker Elevation
Wednesday Afternoon Snow Level
6500'
Wednesday Night Snow Level
5000'
Thursday Morning Snow Level
4000'
Thursday Afternoon Snow Level
4000'
Thursday Night Snow Level
2500'
Washington Pass Elevation
Wednesday Afternoon Snow Level
6500'
Wednesday Night Snow Level
5500'
Thursday Morning Snow Level
4000'
Thursday Afternoon Snow Level
4500'
Thursday Night Snow Level
2500'
Leavenworth Elevation
Wednesday Afternoon Snow Level
None'
Wednesday Night Snow Level
None'
Thursday Morning Snow Level
None'
Thursday Afternoon Snow Level
None'
Thursday Night Snow Level
None'
Stevens Pass Elevation
Wednesday Afternoon Snow Level
None'
Wednesday Night Snow Level
None'
Thursday Morning Snow Level
None'
Thursday Afternoon Snow Level
None'
Thursday Night Snow Level
None'
Snoqualmie Pass Elevation
Wednesday Afternoon Snow Level
7500'
Wednesday Night Snow Level
6500'
Thursday Morning Snow Level
4500'
Thursday Afternoon Snow Level
4000'
Thursday Night Snow Level
2500'
Mt. Rainier & Crystal Elevation
Wednesday Afternoon Snow Level
None'
Wednesday Night Snow Level
None'
Thursday Morning Snow Level
None'
Thursday Afternoon Snow Level
None'
Thursday Night Snow Level
None'
Mt. Hood Elevation
Wednesday Afternoon Snow Level
9500'
Wednesday Night Snow Level
9000'
Thursday Morning Snow Level
8500'
Thursday Afternoon Snow Level
8500'
Thursday Night Snow Level
4500'

* Easterly flow in the Cascade Passes can cause locally lower Snow or Freezing levels than areas further west.
Freezing Level is when no precipitation is forecast.

Precipitation Forecast

Thursday Friday
Hurricane Ridge 0 0
Mt Baker Ski Area 0.25 - 0.50 0.25 - 0.50
Washington Pass 0.10 0.25 - 0.50
Stevens Pass LT 0.10 0.75 - 1.00
Snoqualmie Pass LT 0.10 0.25 - 0.50
Mission Ridge 0 0
Crystal Mt LT 0.10 0
Paradise LT 0.25 LT 0.10
White Pass 0 LT 0.10
Mt Hood Meadows 0 0
0 0
Hurricane Ridge Precipitation Forecast
Thursday 0
Friday 0
Mt Baker Ski Area Precipitation Forecast
Thursday 0.25 - 0.50
Friday 0.25 - 0.50
Washington Pass Precipitation Forecast
Thursday 0.10
Friday 0.25 - 0.50
Stevens Pass Precipitation Forecast
Thursday LT 0.10
Friday 0.75 - 1.00
Snoqualmie Pass Precipitation Forecast
Thursday LT 0.10
Friday 0.25 - 0.50
Mission Ridge Precipitation Forecast
Thursday 0
Friday 0
Crystal Mt Precipitation Forecast
Thursday LT 0.10
Friday 0
Paradise Precipitation Forecast
Thursday LT 0.25
Friday LT 0.10
White Pass Precipitation Forecast
Thursday 0
Friday LT 0.10
Mt Hood Meadows Precipitation Forecast
Thursday 0
Friday 0
Timberline Precipitation Forecast
Thursday 0
Friday 0

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Wednesday Afternoon W 20 - 30 W 15 - 25 W 10 - 20 --- None - None W 10 - 20
Wednesday Night WSW 25 - 40 WSW 20 - 35 WSW 30 - 40 --- None - None WSW 30 - 40
Thursday Morning WSW 25 - 35 WSW 20 - 30 WSW 30 - 40 --- None - None WSW 30 - 40
Thursday Afternoon WSW 20 - 30 WSW 10 - 20 WSW 25 - 35 --- None - None W 30 - 40
Hurricane Ridge Elevation
Wednesday Afternoon W 20 - 30
Wednesday Night WSW 25 - 40
Thursday Morning WSW 25 - 35
Thursday Afternoon WSW 20 - 30
Thursday Night WSW 5 - 15
Mt. Baker Elevation
Wednesday Afternoon W 15 - 25
Wednesday Night WSW 20 - 35
Thursday Morning WSW 20 - 30
Thursday Afternoon WSW 10 - 20
Thursday Night SW 5 - 15
Stevens and Snoqualmie Pass Elevation
Wednesday Afternoon W 10 - 20
Wednesday Night WSW 30 - 40
Thursday Morning WSW 30 - 40
Thursday Afternoon WSW 25 - 35
Thursday Night W 5 - 15
Mt. Rainier Elevation
Wednesday Afternoon --- None - None
Wednesday Night --- None - None
Thursday Morning --- None - None
Thursday Afternoon --- None - None
Thursday Night --- None - None
Mt. Hood Elevation
Wednesday Afternoon W 10 - 20
Wednesday Night WSW 30 - 40
Thursday Morning WSW 30 - 40
Thursday Afternoon W 30 - 40
Thursday Night W 20 - 35
Hurricane Ridge Direction - Speed
Wednesday Afternoon W 20 - 30
Wednesday Night WSW 25 - 40
Thursday Morning WSW 25 - 35
Thursday Afternoon WSW 20 - 30
Thursday Night WSW 5 - 15
Mt. Baker Direction - Speed
Wednesday Afternoon W 15 - 25
Wednesday Night WSW 20 - 35
Thursday Morning WSW 20 - 30
Thursday Afternoon WSW 10 - 20
Thursday Night SW 5 - 15
Stevens and Snoqualmie Pass Direction - Speed
Wednesday Afternoon W 10 - 20
Wednesday Night WSW 30 - 40
Thursday Morning WSW 30 - 40
Thursday Afternoon WSW 25 - 35
Thursday Night W 5 - 15
Mt. Rainier Direction - Speed
Wednesday Afternoon --- None - None
Wednesday Night --- None - None
Thursday Morning --- None - None
Thursday Afternoon --- None - None
Thursday Night --- None - None
Mt. Hood Direction - Speed
Wednesday Afternoon W 10 - 20
Wednesday Night WSW 30 - 40
Thursday Morning WSW 30 - 40
Thursday Afternoon W 30 - 40
Thursday Night W 20 - 35

Directions above indicate the direction the wind blows from on the 16-point cardinal scale. These winds indicate "free" winds, or those winds in the atmosphere not influenced by terrain. Topographical effects may produce greater or lower wind speeds in certain locations as well as significant variations in direction.

Free Winds at 9000' (mph)

Mt. Baker Washington Pass Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Wednesday Afternoon W 45 - 65 W 50 - 70 W 50 - 70 --- None - None WNW 25 - 35
Wednesday Night WSW 50 - 70 WSW 60 - 80 WSW 60 - 80 --- None - None W 50 - 70
Thursday Morning WSW 35 - 45 WSW 50 - 70 W 40 - 60 --- None - None W 60 - 80
Thursday Afternoon W 25 - 35 WSW 30 - 40 W 40 - 60 --- None - None W 55 - 75
Mt. Baker Direction - Speed
Wednesday Afternoon W 45 - 65
Wednesday Night WSW 50 - 70
Thursday Morning WSW 35 - 45
Thursday Afternoon W 25 - 35
Thursday Night W 10 - 20
Washington Pass Direction - Speed
Wednesday Afternoon W 50 - 70
Wednesday Night WSW 60 - 80
Thursday Morning WSW 50 - 70
Thursday Afternoon WSW 30 - 40
Thursday Night W 15 - 25
Stevens and Snoqualmie Pass Direction - Speed
Wednesday Afternoon W 50 - 70
Wednesday Night WSW 60 - 80
Thursday Morning W 40 - 60
Thursday Afternoon W 40 - 60
Thursday Night WNW 35 - 55
Mt. Rainier Direction - Speed
Wednesday Afternoon --- None - None
Wednesday Night --- None - None
Thursday Morning --- None - None
Thursday Afternoon --- None - None
Thursday Night --- None - None
Mt. Hood Direction - Speed
Wednesday Afternoon WNW 25 - 35
Wednesday Night W 50 - 70
Thursday Morning W 60 - 80
Thursday Afternoon W 55 - 75
Thursday Night NW 45 - 65

Extended Weather Synopsis for Friday night through Sunday

A moderate jet will remain over the area on Friday, with some light snow showers on a light W-NW flow along the west slopes of the Cascades.

Late Friday into Friday night, an upper trough to the NE will retrograde to the west, spawning a back-door coldfront that pushes south and may bring a few snow showers to the Mt. Hood area on Friday night. Over Washington, expect clearing skies and light winds with low freezing levels.

Saturday, should feature a brief period of relatively cool high pressure with clear skies, rebounding freezing levels, and light winds as a northward tongue of our trusty offshore high pressure slides east to replace the southward-moving shortwave trough. 

The high pressure should hold through Saturday night with clear skies and low freezing levels.

Models agree that a storm will impact the northwest at some point on Saturday on a NW flow coming down the back-side of the high pressure ridge, but the models disagree regarding the track. Some models take the storm offshore into central Oregon, cutting off the potential for much moisture getting into our mountains. Other tracks take it directly into Washington during the daylight hours on Sunday. At this time, the upper and surface low look to bring another round of colder air and the potential for snow to lower elevations.

Extended Weather

Olympics, Washington Cascades and Mt. Hood Area
Friday Decreasing light snow showers, heaviest in weak convergence, in the Washington Cascades west of the crest. Clearing Saturday night, except snow showers lingering over northern Oregon.
Saturday Clear and fair weather Saturday and Saturday night.

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Friday Snow Level None' - None' None' - None' None' - None'
Friday Night Snow Level None' - None' None' - None' None' - None'
Saturday Snow Level None' - None' None' - None' None' - None'
Saturday Night Snow Level None' - None' None' - None' None' - None'
Mt. Baker Elevation
Friday Snow Level
None' - None'
Friday Night Snow Level
None' - None'
Saturday Snow Level
None' - None'
Saturday Night Snow Level
None' - None'
Sunday Snow Level
None' - None'
Snoqualmie Pass Elevation
Friday Snow Level
None' - None'
Friday Night Snow Level
None' - None'
Saturday Snow Level
None' - None'
Saturday Night Snow Level
None' - None'
Sunday Snow Level
None' - None'
Mt. Hood Elevation
Friday Snow Level
None' - None'
Friday Night Snow Level
None' - None'
Saturday Snow Level
None' - None'
Saturday Night Snow Level
None' - None'
Sunday Snow Level
None' - None'

* Easterly flow in the Cascade Passes can cause locally lower Snow or Freezing levels than areas further west.
Freezing Level is when no precipitation is forecast.

Jump to: Weather Forecast I Snow/Freezing Level I Precipitation I Free Winds 5k I Free Winds 9k I Extended Weather

The NWAC program is administered by the USDA-Forest Service and operates from the National Weather Service Forecast Office in Seattle. NWAC services are made possible by important collaboration and support from a wide variety of federal, state and private cooperators.