Issued: 2:04 PM PST Monday, December 6, 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

On Monday a splitting frontal system produced light to locally moderate precipitation for areas along the west slopes of the Cascades and Passes. While the system started cool, milder air has mixed in for most areas as of Monday afternoon along the west slopes of the Cascades and Passes. Milder air will work its way over to the eastern slopes of the Cascades Monday night as scattered showers diminish. While showers will be few and far between on Tuesday there should be plenty of low cloudy cover, especially along the north and the central Cascades. Snow/freezing levels will remain quite mild on Tuesday as well. 

A frontal system dropping down from the Gulf of Alaska will pass through the Cascades Wednesday morning. Look for dropping snow levels, snow showers, and increasing westerly ridgeline winds during the day. The heaviest snowfall will likely be aimed into the west slopes of the Cascades from Snoqualmie Pass to the Canadian border. 

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
Monday Night Cloudy with isolated rain and snow showers decreasing overnight.
Tuesday Cloudy.
Monday Night Cloudy with scattered rain and snow showers decreasing overnight.
Tuesday Cloudy with isolated rain and snow showers. Variable winds at Pass level.
Monday Night Cloudy with scattered rain and snow showers decreasing overnight.
Tuesday Cloudy with isolated rain and snow showers.
Monday Night Cloudy with scattered rain and snow showers decreasing overnight.
Tuesday Cloudy with sunbreaks possible Crystal/White Pass areas.
Monday Night Cloudy with scattered rain and snow showers decreasing overnight. Light west winds at Pass level.
Tuesday Cloudy with isolated rain and snow showers. Variable winds at Pass level.
Monday Night Cloudy with scattered rain and snow showers decreasing overnight. Light west winds at Pass level.
Tuesday Cloudy with isolated rain and snow showers. Variable winds at Pass level.
Monday Night Cloudy with isolated rain and snow showers decreasing overnight.
Tuesday Cloudy.
Monday Night Mostly cloudy with isolated rain and snow showers decreasing overnight.
Tuesday Mostly cloudy.
Monday Night Mostly cloudy with isolated rain and snow showers decreasing overnight.
Tuesday Mostly cloudy.
Monday Night Cloudy with rain and snow showers becoming scattered overnight.
Tuesday Mostly cloudy with isolated rain and snow showers.

Issued: 2:04 PM PST Monday, December 6, 2021

Precipitation (in)

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

Issued: 2:04 PM PST Monday, December 6, 2021

Snow Level (ft)

Monday Evening Monday Night Tuesday Morning Tuesday Afternoon Tuesday Evening Tuesday Night Wednesday Morning Wednesday Afternoon
Olympics 5500' 5500' 5000' 5500' 5000' 4000' 2500' 1500'
West North 4000' 4500' 4500' 4500' 4500' 3500' 2500' 1500'
West Central 4500' 4500' 4500' 5000' 5000' 4500' 2500' 1500'
West South 6000' 6000' 5500' 6000' 5500' 5000' 3000' 2000'
Stevens Pass 4000' 4500' 4500' 4500' 4500' 3500' 2500' 1500'
Snoqualmie Pass 5000' 5500' 5000' 5000' 5000' 4000' 3000' 1500'
East North 2000' 3500' 4000' 4000' 3500' 3000' 1500' 1500'
East Central 3000' 3000' 4000' 4500' 4500' 3000' 2000' 2000'
East South 5000' 5500' 5500' 6000' 5500' 3000' 3000' 2000'
Mt. Hood 6500' 7000' 7000' 7500' 6000' 4500' 4500' 3000'
Olympics Elevation
Monday Evening 5500'
Monday Night 5500'
Tuesday Morning 5000'
Tuesday Afternoon 5500'
Tuesday Evening 5000'
Tuesday Night 4000'
Wednesday Morning 2500'
Wednesday Afternoon 1500'
West North Elevation
Monday Evening 4000'
Monday Night 4500'
Tuesday Morning 4500'
Tuesday Afternoon 4500'
Tuesday Evening 4500'
Tuesday Night 3500'
Wednesday Morning 2500'
Wednesday Afternoon 1500'
West Central Elevation
Monday Evening 4500'
Monday Night 4500'
Tuesday Morning 4500'
Tuesday Afternoon 5000'
Tuesday Evening 5000'
Tuesday Night 4500'
Wednesday Morning 2500'
Wednesday Afternoon 1500'
West South Elevation
Monday Evening 6000'
Monday Night 6000'
Tuesday Morning 5500'
Tuesday Afternoon 6000'
Tuesday Evening 5500'
Tuesday Night 5000'
Wednesday Morning 3000'
Wednesday Afternoon 2000'
Stevens Pass Elevation
Monday Evening 4000'
Monday Night 4500'
Tuesday Morning 4500'
Tuesday Afternoon 4500'
Tuesday Evening 4500'
Tuesday Night 3500'
Wednesday Morning 2500'
Wednesday Afternoon 1500'
Snoqualmie Pass Elevation
Monday Evening 5000'
Monday Night 5500'
Tuesday Morning 5000'
Tuesday Afternoon 5000'
Tuesday Evening 5000'
Tuesday Night 4000'
Wednesday Morning 3000'
Wednesday Afternoon 1500'
East North Elevation
Monday Evening 2000'
Monday Night 3500'
Tuesday Morning 4000'
Tuesday Afternoon 4000'
Tuesday Evening 3500'
Tuesday Night 3000'
Wednesday Morning 1500'
Wednesday Afternoon 1500'
East Central Elevation
Monday Evening 3000'
Monday Night 3000'
Tuesday Morning 4000'
Tuesday Afternoon 4500'
Tuesday Evening 4500'
Tuesday Night 3000'
Wednesday Morning 2000'
Wednesday Afternoon 2000'
East South Elevation
Monday Evening 5000'
Monday Night 5500'
Tuesday Morning 5500'
Tuesday Afternoon 6000'
Tuesday Evening 5500'
Tuesday Night 3000'
Wednesday Morning 3000'
Wednesday Afternoon 2000'
Mt. Hood Elevation
Monday Evening 6500'
Monday Night 7000'
Tuesday Morning 7000'
Tuesday Afternoon 7500'
Tuesday Evening 6000'
Tuesday Night 4500'
Wednesday Morning 4500'
Wednesday Afternoon 3000'

Issued: 2:04 PM PST Monday, December 6, 2021

5000' Temperatures (°F)

Monday Night Tuesday
Max / Min Max / Min
Olympics 35 / 29 33 / 27
West North 32 / 29 32 / 31
West Central 33 / 31 33 / 32
West South 34 / 32 36 / 34
Stevens Pass 33 / 31 34 / 33
Snoqualmie Pass 33 / 32 34 / 33
East North 31 / 25 33 / 29
East Central 33 / 31 34 / 33
East South 34 / 33 37 / 33
Mt. Hood 37 / 35 40 / 37
Olympics 5000' Temperature Forecast
(Max / Min)
Monday Night 35 / 29
Tuesday 33 / 27
West North 5000' Temperature Forecast
(Max / Min)
Monday Night 32 / 29
Tuesday 32 / 31
West Central 5000' Temperature Forecast
(Max / Min)
Monday Night 33 / 31
Tuesday 33 / 32
West South 5000' Temperature Forecast
(Max / Min)
Monday Night 34 / 32
Tuesday 36 / 34
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Monday Night 33 / 31
Tuesday 34 / 33
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Monday Night 33 / 32
Tuesday 34 / 33
East North 5000' Temperature Forecast
(Max / Min)
Monday Night 31 / 25
Tuesday 33 / 29
East Central 5000' Temperature Forecast
(Max / Min)
Monday Night 33 / 31
Tuesday 34 / 33
East South 5000' Temperature Forecast
(Max / Min)
Monday Night 34 / 33
Tuesday 37 / 33
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Monday Night 37 / 35
Tuesday 40 / 37

Issued: 2:04 PM PST Monday, December 6, 2021

Ridgeline Winds (mph)

Monday Evening Monday Night Tuesday Morning Tuesday Afternoon
Olympics SW 5-15 SW 5-15 SW 5-15 SW 5-15
West North WSW 5-15 SW 5-15 SW 5-15 SW 10-20
West Central WSW 0-10 WSW 5-15 SW 5-15 SW 5-15
West South W 5-15 WSW 10-20 WSW 10-20 WSW 10-20
Stevens Pass W 5-15 WSW 10-20 W 15-25 W 10-20
Snoqualmie Pass W 15-25 W 15-25 W 15-25 W 15-25
East North WSW 10-20 WSW 10-20 WSW 10-20 WSW 10-20
East Central W 10-20 W 15-25 W 15-25 W 20-30
East South W 10-20 W 15-25 W 15-25 W 20-30
Mt. Hood W 15-25 W 15-25 WSW 15-25 WSW 20-30
Olympics Ridgeline Winds (mph)
Monday Evening SW 5-15
Monday Night SW 5-15
Tuesday Morning SW 5-15
Tuesday Afternoon SW 5-15
West North Ridgeline Winds (mph)
Monday Evening WSW 5-15
Monday Night SW 5-15
Tuesday Morning SW 5-15
Tuesday Afternoon SW 10-20
West Central Ridgeline Winds (mph)
Monday Evening WSW 0-10
Monday Night WSW 5-15
Tuesday Morning SW 5-15
Tuesday Afternoon SW 5-15
West South Ridgeline Winds (mph)
Monday Evening W 5-15
Monday Night WSW 10-20
Tuesday Morning WSW 10-20
Tuesday Afternoon WSW 10-20
Stevens Pass Ridgeline Winds (mph)
Monday Evening W 5-15
Monday Night WSW 10-20
Tuesday Morning W 15-25
Tuesday Afternoon W 10-20
Snoqualmie Pass Ridgeline Winds (mph)
Monday Evening W 15-25
Monday Night W 15-25
Tuesday Morning W 15-25
Tuesday Afternoon W 15-25
East North Ridgeline Winds (mph)
Monday Evening WSW 10-20
Monday Night WSW 10-20
Tuesday Morning WSW 10-20
Tuesday Afternoon WSW 10-20
East Central Ridgeline Winds (mph)
Monday Evening W 10-20
Monday Night W 15-25
Tuesday Morning W 15-25
Tuesday Afternoon W 20-30
East South Ridgeline Winds (mph)
Monday Evening W 10-20
Monday Night W 15-25
Tuesday Morning W 15-25
Tuesday Afternoon W 20-30
Mt. Hood Ridgeline Winds (mph)
Monday Evening W 15-25
Monday Night W 15-25
Tuesday Morning WSW 15-25
Tuesday Afternoon WSW 20-30

Issued: 2:04 PM PST Monday, December 6, 2021

Extended Weather Synopsis

Wednesday's system will open the door to an upper trough with northwesterly flow aloft moving over the area; good for additional snow accumulations in the form of showers through Thursday.  While not an amazing amount of new snow, snow levels will quite low over this stretch. A stronger system should arrive for the weekend with moderate to heavy precipitation starting sometime Friday afternoon or night. 

Extended Snow Level (ft)

Wednesday Night Thursday Thursday Night Friday
West North 500' 1000' 500' 1000'
Snoqualmie Pass 1000' 1500' 1000' 1500'
Mt. Hood 2000' 2000' 1500' 2000'
West North Elevation
Wednesday Night 500'
Thursday 1000'
Thursday Night 500'
Friday 1000'
Snoqualmie Pass Elevation
Wednesday Night 1000'
Thursday 1500'
Thursday Night 1000'
Friday 1500'
Mt. Hood Elevation
Wednesday Night 2000'
Thursday 2000'
Thursday Night 1500'
Friday 2000'

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

Previous forecast from Dec 5, 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’.