Issued: 2:10 PM PST Tuesday, December 7, 2021
by Dennis D'Amico

Jump to: Weather Forecast I Precipitation I Snow Level I 5000' Temps I Ridgeline Winds I Extended Weather

Weather Synopsis

The long awaited pattern shift to cooler and snowier weather is almost here. On Tuesday afternoon, it's a drippy, mostly cloudy day across the forecast area with mountain temperatures generally above freezing at low and mid elevations.  A Pacific frontal system dropping SE will move light precipitation into the region in Tuesday evening and heavier precipitation inland after midnight. Snow levels will be slow to lower initially Tuesday night but once the cold front passes through the Cascades around mid-morning Wednesday we can expect snow levels and temperatures to drop rapidly during the day.  Behind the front, westerly ridgeline winds will become strong to extreme for much of Wednesday.  A Puget Sound Convergence zone, as well as upslope flow along the west slopes of Cascades, will keep snow showers in the forecast with the highest snowfall accumulations for the western Cascades and Passes from roughly Skagit County down towards the south end of King County. 

A secondary upper level feature will reinvigorate snow showers late Wednesday night through Thursday with even lower snow levels. The axis of the heavier showers will also shift southward from the central Cascades to Mt. Hood.  As the flow aloft becomes more northwesterly and the broad upper trough moves inland, westerly winds will decrease through Thursday.  This will be a nice pattern for snow over the next 48 hrs, with 6-18 in. along the west slopes of the Cascades and Mt Hood and lower amounts for the east slopes of the Cascades especially further east from the Cascade crest. 

Weather Forecast

Olympics
West North
West Central
West South
Stevens Pass
Snoqualmie Pass
East North
East Central
East South
Mt. Hood
Use dropdown to select your zone
Tuesday Night Cloudy with light rain and snow developing in the evening and increasing after midnight. Strong winds developing after midnight.
Wednesday Mostly cloudy with light to occasionally moderate snow showers. Strong winds.
Tuesday Night Cloudy with light rain and snow developing in the evening and increasing after midnight. Strong to extreme winds developing after midnight.
Wednesday Moderate snow showers in the morning, becoming mostly cloudy with scattered light to occasionally moderate snow showers in the afternoon. Strong winds easing in the afternoon.
Tuesday Night Cloudy with light rain and snow developing in the evening and increasing after midnight. Strong winds developing after midnight.
Wednesday Light to moderate snow showers. Strong winds.
Tuesday Night Cloudy with light rain and snow developing in the evening and increasing late tonight.
Wednesday Light snow showers. Strong winds.
Tuesday Night Cloudy with light rain and snow developing in the evening and increasing late tonight. Moderate west winds at Pass and ridgeline level increasing overnight.
Wednesday Light to occasionally moderate snow showers. Strong winds at Pass level. Strong to extreme winds at ridgeline.
Tuesday Night Cloudy with light rain and snow developing in the evening and increasing late tonight. Moderate west winds at Pass and ridgeline level increasing overnight.
Wednesday Light to occasionally moderate snow showers. Strong winds at Pass level. Strong to extreme winds at ridgeline.
Tuesday Night Cloudy with light rain and snow developing in the evening and increasing after midnight. Strong winds developing after midnight.
Wednesday Cloudy with light snow showers, occasionally moderate near the crest. Showers becoming scattered in the afternoon with sunbreaks. Strong winds.
Tuesday Night Cloudy with light rain and snow developing in the evening and increasing after midnight. Strong winds developing after midnight.
Wednesday Cloudy with light snow showers, occasionally moderate near the crest. Showers becoming scattered in the afternoon with sunbreaks. Strong winds.
Tuesday Night Cloudy. Light rain and snow developing late tonight. Strong winds developing late.
Wednesday Cloudy with light snow showers, occasionally moderate near the crest. Showers becoming scattered in the afternoon with sunbreaks. Strong winds.
Tuesday Night Cloudy with light rain and snow developing in the evening and increasing late tonight. Strong winds increasing overnight.
Wednesday Light to occasionally moderate snow showers. Strong to extreme winds.

Issued: 2:10 PM PST Tuesday, December 7, 2021

Precipitation (in)

Tuesday Night Wednesday Wednesday Night Thursday
4 pm - 4 am 4 am - 4 pm 4 pm - 4 am 4 am - 4 pm
Hurricane Ridge 0.25 LT 0.25 LT 0.25 0.25
Mt Baker Ski Area 0.50 0.25 - 0.50 LT 0.25 LT 0.25
Mt. Loop - Barlow Pass 0.50 0.50 0.50 0.50
Stevens Pass 0.25 0.25 - 0.50 0.25 - 0.50 0.25 - 0.50
Snoqualmie Pass 0.25 - 0.50 0.50 0.25 - 0.50 0.50
Crystal Mt LT 0.10 LT 0.25 LT 0.10 0.25
Paradise 0.25 0.25 - 0.50 LT 0.25 0.50 - 0.75
White Pass LT 0.25 LT 0.25 LT 0.10 0.25 - 0.50
Washington Pass LT 0.25 LT 0.25 LT 0.10 LT 0.25
Mission Ridge LT 0.10 LT 0.10 LT 0.10 LT 0.10
Salmon la Sac - Gallagher Head LT 0.25 0.25 LT 0.25 LT 0.25
Tieton River - Darland Mt. LT 0.10 LT 0.10 LT 0.10 LT 0.25
Mt Hood Meadows LT 0.10 0.25 - 0.50 LT 0.10 0.50 - 0.75
Timberline 0.25 0.50 LT 0.25 0
Hurricane Ridge Precipitation (in)
Tuesday Night 0.25
Wednesday LT 0.25
Wednesday Night LT 0.25
Thursday 0.25
Mt Baker Ski Area Precipitation (in)
Tuesday Night 0.50
Wednesday 0.25 - 0.50
Wednesday Night LT 0.25
Thursday LT 0.25
Mt. Loop - Barlow Pass Precipitation (in)
Tuesday Night 0.50
Wednesday 0.50
Wednesday Night 0.50
Thursday 0.50
Stevens Pass Precipitation (in)
Tuesday Night 0.25
Wednesday 0.25 - 0.50
Wednesday Night 0.25 - 0.50
Thursday 0.25 - 0.50
Snoqualmie Pass Precipitation (in)
Tuesday Night 0.25 - 0.50
Wednesday 0.50
Wednesday Night 0.25 - 0.50
Thursday 0.50
Crystal Mt Precipitation (in)
Tuesday Night LT 0.10
Wednesday LT 0.25
Wednesday Night LT 0.10
Thursday 0.25
Paradise Precipitation (in)
Tuesday Night 0.25
Wednesday 0.25 - 0.50
Wednesday Night LT 0.25
Thursday 0.50 - 0.75
White Pass Precipitation (in)
Tuesday Night LT 0.25
Wednesday LT 0.25
Wednesday Night LT 0.10
Thursday 0.25 - 0.50
Washington Pass Precipitation (in)
Tuesday Night LT 0.25
Wednesday LT 0.25
Wednesday Night LT 0.10
Thursday LT 0.25
Mission Ridge Precipitation (in)
Tuesday Night LT 0.10
Wednesday LT 0.10
Wednesday Night LT 0.10
Thursday LT 0.10
Salmon la Sac - Gallagher Head Precipitation (in)
Tuesday Night LT 0.25
Wednesday 0.25
Wednesday Night LT 0.25
Thursday LT 0.25
Tieton River - Darland Mt. Precipitation (in)
Tuesday Night LT 0.10
Wednesday LT 0.10
Wednesday Night LT 0.10
Thursday LT 0.25
Mt Hood Meadows Precipitation (in)
Tuesday Night LT 0.10
Wednesday 0.25 - 0.50
Wednesday Night LT 0.10
Thursday 0.50 - 0.75
Timberline Precipitation (in)
Tuesday Night 0.25
Wednesday 0.50
Wednesday Night LT 0.25
Thursday 0

Issued: 2:10 PM PST Tuesday, December 7, 2021

Snow Level (ft)

Tuesday Evening Tuesday Night Wednesday Morning Wednesday Afternoon Wednesday Evening Wednesday Night Thursday Morning Thursday Afternoon
Olympics 5000' 3500' 2000' 1500' 1500' 1000' 1000' 1500'
West North 4500' 3500' 2000' 1500' 1000' 500' 500' 1000'
West Central 5500' 4000' 2500' 1500' 1000' 1000' 1000' 1500'
West South 6000' 5500' 3500' 2000' 1500' 1500' 1000' 1500'
Stevens Pass 5500' 4000' 2500' 1500' 1500' 1000' 1000' 1500'
Snoqualmie Pass 5500' 4500' 3000' 1500' 1500' 1000' 1000' 1500'
East North 4500' 4000' 3500' 1500' 1500' 500' 500' 1000'
East Central 4500' 4500' 3500' 2000' 2000' 500' 500' 1500'
East South 5500' 5500' 4000' 2500' 2000' 1000' 500' 1500'
Mt. Hood 7000' 5500' 4000' 2500' 2500' 1500' 1000' 2000'
Olympics Elevation
Tuesday Evening 5000'
Tuesday Night 3500'
Wednesday Morning 2000'
Wednesday Afternoon 1500'
Wednesday Evening 1500'
Wednesday Night 1000'
Thursday Morning 1000'
Thursday Afternoon 1500'
West North Elevation
Tuesday Evening 4500'
Tuesday Night 3500'
Wednesday Morning 2000'
Wednesday Afternoon 1500'
Wednesday Evening 1000'
Wednesday Night 500'
Thursday Morning 500'
Thursday Afternoon 1000'
West Central Elevation
Tuesday Evening 5500'
Tuesday Night 4000'
Wednesday Morning 2500'
Wednesday Afternoon 1500'
Wednesday Evening 1000'
Wednesday Night 1000'
Thursday Morning 1000'
Thursday Afternoon 1500'
West South Elevation
Tuesday Evening 6000'
Tuesday Night 5500'
Wednesday Morning 3500'
Wednesday Afternoon 2000'
Wednesday Evening 1500'
Wednesday Night 1500'
Thursday Morning 1000'
Thursday Afternoon 1500'
Stevens Pass Elevation
Tuesday Evening 5500'
Tuesday Night 4000'
Wednesday Morning 2500'
Wednesday Afternoon 1500'
Wednesday Evening 1500'
Wednesday Night 1000'
Thursday Morning 1000'
Thursday Afternoon 1500'
Snoqualmie Pass Elevation
Tuesday Evening 5500'
Tuesday Night 4500'
Wednesday Morning 3000'
Wednesday Afternoon 1500'
Wednesday Evening 1500'
Wednesday Night 1000'
Thursday Morning 1000'
Thursday Afternoon 1500'
East North Elevation
Tuesday Evening 4500'
Tuesday Night 4000'
Wednesday Morning 3500'
Wednesday Afternoon 1500'
Wednesday Evening 1500'
Wednesday Night 500'
Thursday Morning 500'
Thursday Afternoon 1000'
East Central Elevation
Tuesday Evening 4500'
Tuesday Night 4500'
Wednesday Morning 3500'
Wednesday Afternoon 2000'
Wednesday Evening 2000'
Wednesday Night 500'
Thursday Morning 500'
Thursday Afternoon 1500'
East South Elevation
Tuesday Evening 5500'
Tuesday Night 5500'
Wednesday Morning 4000'
Wednesday Afternoon 2500'
Wednesday Evening 2000'
Wednesday Night 1000'
Thursday Morning 500'
Thursday Afternoon 1500'
Mt. Hood Elevation
Tuesday Evening 7000'
Tuesday Night 5500'
Wednesday Morning 4000'
Wednesday Afternoon 2500'
Wednesday Evening 2500'
Wednesday Night 1500'
Thursday Morning 1000'
Thursday Afternoon 2000'

Issued: 2:10 PM PST Tuesday, December 7, 2021

5000' Temperatures (°F)

Tuesday Night Wednesday
Max / Min Max / Min
Olympics 33 / 28 26 / 20
West North 33 / 28 26 / 19
West Central 35 / 30 27 / 19
West South 35 / 31 27 / 20
Stevens Pass 34 / 31 27 / 20
Snoqualmie Pass 35 / 30 28 / 20
East North 33 / 29 27 / 20
East Central 34 / 30 29 / 21
East South 36 / 31 30 / 25
Mt. Hood 39 / 33 31 / 27
Olympics 5000' Temperature Forecast
(Max / Min)
Tuesday Night 33 / 28
Wednesday 26 / 20
West North 5000' Temperature Forecast
(Max / Min)
Tuesday Night 33 / 28
Wednesday 26 / 19
West Central 5000' Temperature Forecast
(Max / Min)
Tuesday Night 35 / 30
Wednesday 27 / 19
West South 5000' Temperature Forecast
(Max / Min)
Tuesday Night 35 / 31
Wednesday 27 / 20
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Tuesday Night 34 / 31
Wednesday 27 / 20
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Tuesday Night 35 / 30
Wednesday 28 / 20
East North 5000' Temperature Forecast
(Max / Min)
Tuesday Night 33 / 29
Wednesday 27 / 20
East Central 5000' Temperature Forecast
(Max / Min)
Tuesday Night 34 / 30
Wednesday 29 / 21
East South 5000' Temperature Forecast
(Max / Min)
Tuesday Night 36 / 31
Wednesday 30 / 25
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Tuesday Night 39 / 33
Wednesday 31 / 27

Issued: 2:10 PM PST Tuesday, December 7, 2021

Ridgeline Winds (mph)

Tuesday Evening Tuesday Night Wednesday Morning Wednesday Afternoon
Olympics SW 5-15 SW 20-30 W 20-30 W 15-25
West North S 15-25 SW 30-40 W 20-30 W 10-20
West Central SW 20-30 SW 25-35 W 30-40 W 25-35
West South WSW 10-20 SW 15-25 W 20-30 WNW 25-35
Stevens Pass WSW 10-20 WSW 15-25 W 35-50 WNW 30-40
Snoqualmie Pass WSW 15-25 W 15-25 W 35-50 W 35-50
East North WSW 15-25 SW 25-35 W 30-40 W 25-35
East Central WSW 15-25 WSW 20-30 WNW 40-55 WNW 40-55
East South WSW 15-25 W 25-35 W 40-55 W 35-50
Mt. Hood SW 25-35 WSW 30-40 W 40-55 W 40-55
Olympics Ridgeline Winds (mph)
Tuesday Evening SW 5-15
Tuesday Night SW 20-30
Wednesday Morning W 20-30
Wednesday Afternoon W 15-25
West North Ridgeline Winds (mph)
Tuesday Evening S 15-25
Tuesday Night SW 30-40
Wednesday Morning W 20-30
Wednesday Afternoon W 10-20
West Central Ridgeline Winds (mph)
Tuesday Evening SW 20-30
Tuesday Night SW 25-35
Wednesday Morning W 30-40
Wednesday Afternoon W 25-35
West South Ridgeline Winds (mph)
Tuesday Evening WSW 10-20
Tuesday Night SW 15-25
Wednesday Morning W 20-30
Wednesday Afternoon WNW 25-35
Stevens Pass Ridgeline Winds (mph)
Tuesday Evening WSW 10-20
Tuesday Night WSW 15-25
Wednesday Morning W 35-50
Wednesday Afternoon WNW 30-40
Snoqualmie Pass Ridgeline Winds (mph)
Tuesday Evening WSW 15-25
Tuesday Night W 15-25
Wednesday Morning W 35-50
Wednesday Afternoon W 35-50
East North Ridgeline Winds (mph)
Tuesday Evening WSW 15-25
Tuesday Night SW 25-35
Wednesday Morning W 30-40
Wednesday Afternoon W 25-35
East Central Ridgeline Winds (mph)
Tuesday Evening WSW 15-25
Tuesday Night WSW 20-30
Wednesday Morning WNW 40-55
Wednesday Afternoon WNW 40-55
East South Ridgeline Winds (mph)
Tuesday Evening WSW 15-25
Tuesday Night W 25-35
Wednesday Morning W 40-55
Wednesday Afternoon W 35-50
Mt. Hood Ridgeline Winds (mph)
Tuesday Evening SW 25-35
Tuesday Night WSW 30-40
Wednesday Morning W 40-55
Wednesday Afternoon W 40-55

Issued: 2:10 PM PST Tuesday, December 7, 2021

Extended Weather Synopsis

Our active pattern will continue through the weekend with a strong Pacific frontal system lined up for Saturday.  Don't expect many breaks in the action as light warm frontal precipitation will spread over the mountains on Friday.  Snow levels will stay cool, but slowly rise Friday and further Friday night as heavier precipitation moves into the area. It's a bit too far out to nail down specific snow levels, but it does seem like there will be a sliver of warm air ahead of the cold front passage on Saturday, that will push snow levels up to mid-elevations in many areas, especially south of Snoqualmie Pass.   

Extended Snow Level (ft)

Thursday Night Friday Friday Night* Saturday *
West North 0 1500' 2500' 3000'
Snoqualmie Pass 500' 2000' 2500' 3000'
Mt. Hood 1500' 2500' 3500' 4500'
West North Elevation
Thursday Night 0'
Friday 1500'
Friday Night* 2500'
Saturday * 3000'
Snoqualmie Pass Elevation
Thursday Night 500'
Friday 2000'
Friday Night* 2500'
Saturday * 3000'
Mt. Hood Elevation
Thursday Night 1500'
Friday 2500'
Friday Night* 3500'
Saturday * 4500'

Jump to: Weather Forecast I Precipitation I Snow Level I 5000' Temps I Ridgeline Winds I Extended Weather

Previous forecast from Dec 6, 2021

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.

The 5000’ temperature forecast does not imply a trend over the 12 hr period and only represents the max and min temperatures within a 12 hr period in the zone. The 6-hr snow level forecast, the forecast discussion, and weather forecast sections may add detail regarding temperature trends.

The snow level forecast represents the general snow level over a 6 hr time period. Freezing levels are forecast when precipitation is not expected.

*Easterly or offshore flow is highlighted with an asterisk when we expect relatively cool east winds in the major Cascade Passes. Easterly flow will often lead to temperature inversions and is a key variable for forecasting precipitation type in the Cascade Passes. Strong easterly flow events can affect terrain on a more regional scale.

Ridgeline winds are the average wind speed and direction over a 6 hr time period.

The wind forecast represents an elevation range instead of a single elevation slice. The elevation range overlaps with the near and above treeline elevation bands in the avalanche forecast and differs per zone.

Wind direction indicates the direction the wind originates or comes from on the 16-point compass rose.

Water Equivalent (WE) is the liquid water equivalent of all precipitation types; rain, snow, ice pellets, etc., forecast to the hundredth of an inch at specific locations. To use WE as a proxy for snowfall amounts, start with a snow to water ratio of 10:1 (10 inches of snow = 1 inch WE). Temperatures at or near freezing will generally have a lower ratio (heavy wet snow) and very cold temperatures can have a much higher ratio (dry fluffy snow).

The label LT, is shorthand for ‘less than’.