Issued: 4:07 PM PST Sunday, December 5, 2021
by Robert Hahn

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

Weather Synopsis

While the long-range pattern looks good for snow production, the ingredients for significant snowfall with the first system look less favorable as time passes.

An occluded frontal system with a detached surface low-pressure center approaches the region Sunday night. Cold temperatures remain in place across the region. Clouds should lower and thicken during the evening hours with light snow developing in most mountain locales overnight.

The warm front, cold front, and occluded fronts move through the region on Monday with light to occasionally moderate snowfall. Snow should peak Monday morning before decreasing in the afternoon. Snow levels rise during the day and increase further overnight after the fronts pass and weak "dirty" ridging pushes into the area with moisture and light rain/snow showers spilling over the top Monday night. Snoqualmie Pass can expect a changeover to rain late Monday with a brief period of freezing rain possible depending on variable east and west pass-level winds. We expect 2-6" of snow from this system for Mt. Baker, Steven Pass, Paradise, and Mt. Hood. Amounts on the east slopes of the Cascades should be in the 1-3" range.

Temperatures will be unseasonably mild Monday night and Tuesday with moisture continuing to trickle into the region. Snow levels rise to 4000-7000 ft by the afternoon as light rain and snow showers may pick ahead of the next trough moving into the near-shore waters.

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
Sunday Night Clouds lowering and thickening in the evening with light snow developing overnight.
Monday Light snowfall tapering in the afternoon. Snow levels rise quickly late in the day.
Sunday Night Clouds lowering and thickening in the evening with light snow developing overnight.
Monday Light snow decreasing slightly in the afternoon.
Sunday Night Clouds lowering and thickening in the evening with light snow developing overnight.
Monday Light to moderate snow heaviest northern part.
Sunday Night Clouds lowering and thickening in the evening with light snow developing overnight.
Monday Moderate rain and snow at Paradise, light rain and snow at Crystal and White Passes.
Sunday Night Clouds lowering and thickening in the evening with light snow developing overnight. Light E winds at the Pass.
Monday Light snow. Variable light E and W wind at the Pass.
Sunday Night Clouds lowering and thickening in the evening with light snow developing overnight. Light E winds at the Pass.
Monday Light snow in the morning, potentially mixing with rain to elevations above Pass level by late afternoon. Variable light E and W wind at the Pass.
Sunday Night Clouds lowering and thickening in the evening with light snow developing overnight.
Monday Light snow.
Sunday Night Clouds lowering and thickening in the evening with light snow developing overnight.
Monday Light snow, potentially mixing with rain at lower elevations late in the day.
Sunday Night Clouds lowering and thickening in the evening with light snow developing overnight.
Monday Light rain and snow at times.
Sunday Night Clouds lowering and thickening in the evening with light snow developing overnight. Increasing moderate ridgeline winds potentially becoming strong.
Monday Light to occasionally moderate rain and snow. Moderate to strong ridgeline winds peaking early in the day.

Issued: 4:07 PM PST Sunday, December 5, 2021

Precipitation (in)

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

Issued: 4:07 PM PST Sunday, December 5, 2021

Snow Level (ft)

Sunday Evening Sunday Night Monday Morning Monday Afternoon Monday Evening Monday Night Tuesday Morning Tuesday Afternoon
Olympics 2000' 1000' 1500' 2500' 6000' 6500' 7000' 7000'
West North 1000' 500' 500' 1500' 2000' 3000' 4000' 4000'
West Central 1500' 500' 1500' 2000' 3000' 4500' 4500' 5000'
West South 2000' 1500' 2500' 3500' 4500' 5500' 6000' 6000'
Stevens Pass 1500' 1000' 1000' 2000' 3000' 4000' 3500' 5000'
Snoqualmie Pass 1500' 1000' 1000' 3000' 4000' 5000' 4500' 5500'
East North 1000' 500' 500' 2000' 2000' 2500' 3500' 4000'
East Central 1500' 1000' 1500' 3000' 2500' 3500' 4000' 5500'
East South 2500' 1500' 2500' 3500' 4500' 5000' 6000' 6000'
Mt. Hood 3500' 5500' 4000' 6500' 6500' 6500' 7000' 7000'
Olympics Elevation
Sunday Evening 2000'
Sunday Night 1000'
Monday Morning 1500'
Monday Afternoon 2500'
Monday Evening 6000'
Monday Night 6500'
Tuesday Morning 7000'
Tuesday Afternoon 7000'
West North Elevation
Sunday Evening 1000'
Sunday Night 500'
Monday Morning 500'
Monday Afternoon 1500'
Monday Evening 2000'
Monday Night 3000'
Tuesday Morning 4000'
Tuesday Afternoon 4000'
West Central Elevation
Sunday Evening 1500'
Sunday Night 500'
Monday Morning 1500'
Monday Afternoon 2000'
Monday Evening 3000'
Monday Night 4500'
Tuesday Morning 4500'
Tuesday Afternoon 5000'
West South Elevation
Sunday Evening 2000'
Sunday Night 1500'
Monday Morning 2500'
Monday Afternoon 3500'
Monday Evening 4500'
Monday Night 5500'
Tuesday Morning 6000'
Tuesday Afternoon 6000'
Stevens Pass Elevation
Sunday Evening 1500'
Sunday Night 1000'
Monday Morning 1000'
Monday Afternoon 2000'
Monday Evening 3000'
Monday Night 4000'
Tuesday Morning 3500'
Tuesday Afternoon 5000'
Snoqualmie Pass Elevation
Sunday Evening 1500'
Sunday Night 1000'
Monday Morning 1000'
Monday Afternoon 3000'
Monday Evening 4000'
Monday Night 5000'
Tuesday Morning 4500'
Tuesday Afternoon 5500'
East North Elevation
Sunday Evening 1000'
Sunday Night 500'
Monday Morning 500'
Monday Afternoon 2000'
Monday Evening 2000'
Monday Night 2500'
Tuesday Morning 3500'
Tuesday Afternoon 4000'
East Central Elevation
Sunday Evening 1500'
Sunday Night 1000'
Monday Morning 1500'
Monday Afternoon 3000'
Monday Evening 2500'
Monday Night 3500'
Tuesday Morning 4000'
Tuesday Afternoon 5500'
East South Elevation
Sunday Evening 2500'
Sunday Night 1500'
Monday Morning 2500'
Monday Afternoon 3500'
Monday Evening 4500'
Monday Night 5000'
Tuesday Morning 6000'
Tuesday Afternoon 6000'
Mt. Hood Elevation
Sunday Evening 3500'
Sunday Night 5500'
Monday Morning 4000'
Monday Afternoon 6500'
Monday Evening 6500'
Monday Night 6500'
Tuesday Morning 7000'
Tuesday Afternoon 7000'

Issued: 4:07 PM PST Sunday, December 5, 2021

5000' Temperatures (°F)

Sunday Night Monday
Max / Min Max / Min
Olympics 27 / 21 34 / 28
West North 19 / 15 29 / 20
West Central 22 / 18 30 / 22
West South 26 / 19 33 / 26
Stevens Pass 22 / 17 31 / 22
Snoqualmie Pass 22 / 17 32 / 23
East North 17 / 13 25 / 17
East Central 22 / 17 32 / 23
East South 26 / 19 33 / 27
Mt. Hood 34 / 24 36 / 31
Olympics 5000' Temperature Forecast
(Max / Min)
Sunday Night 27 / 21
Monday 34 / 28
West North 5000' Temperature Forecast
(Max / Min)
Sunday Night 19 / 15
Monday 29 / 20
West Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 22 / 18
Monday 30 / 22
West South 5000' Temperature Forecast
(Max / Min)
Sunday Night 26 / 19
Monday 33 / 26
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 22 / 17
Monday 31 / 22
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 22 / 17
Monday 32 / 23
East North 5000' Temperature Forecast
(Max / Min)
Sunday Night 17 / 13
Monday 25 / 17
East Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 22 / 17
Monday 32 / 23
East South 5000' Temperature Forecast
(Max / Min)
Sunday Night 26 / 19
Monday 33 / 27
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Sunday Night 34 / 24
Monday 36 / 31

Issued: 4:07 PM PST Sunday, December 5, 2021

Ridgeline Winds (mph)

Sunday Evening Sunday Night Monday Morning Monday Afternoon
Olympics WSW 0-10 WSW 10-20 WSW 15-25 WSW 10-20
West North SW 5-15 SSW 5-15 SSW 5-15 SW 5-15
West Central SSW 5-15 SW 10-20 SW 10-20 WSW 10-20
West South SW 0-10 SW 5-15 WSW 10-20 WSW 10-20
Stevens Pass SSW 0-10 SW 5-15 WSW 10-20 W 10-20
Snoqualmie Pass S 0-10 WSW 10-20 WSW 10-20 W 10-20
East North SW 5-15 SW 10-20 WSW 10-20 W 5-15
East Central WSW 5-15 W 15-25 W 20-30 W 15-25
East South W 5-15 WSW 10-20 WSW 10-20 W 5-15
Mt. Hood WNW 10-20 WSW 25-35 WSW 25-35 W 20-30
Olympics Ridgeline Winds (mph)
Sunday Evening WSW 0-10
Sunday Night WSW 10-20
Monday Morning WSW 15-25
Monday Afternoon WSW 10-20
West North Ridgeline Winds (mph)
Sunday Evening SW 5-15
Sunday Night SSW 5-15
Monday Morning SSW 5-15
Monday Afternoon SW 5-15
West Central Ridgeline Winds (mph)
Sunday Evening SSW 5-15
Sunday Night SW 10-20
Monday Morning SW 10-20
Monday Afternoon WSW 10-20
West South Ridgeline Winds (mph)
Sunday Evening SW 0-10
Sunday Night SW 5-15
Monday Morning WSW 10-20
Monday Afternoon WSW 10-20
Stevens Pass Ridgeline Winds (mph)
Sunday Evening SSW 0-10
Sunday Night SW 5-15
Monday Morning WSW 10-20
Monday Afternoon W 10-20
Snoqualmie Pass Ridgeline Winds (mph)
Sunday Evening S 0-10
Sunday Night WSW 10-20
Monday Morning WSW 10-20
Monday Afternoon W 10-20
East North Ridgeline Winds (mph)
Sunday Evening SW 5-15
Sunday Night SW 10-20
Monday Morning WSW 10-20
Monday Afternoon W 5-15
East Central Ridgeline Winds (mph)
Sunday Evening WSW 5-15
Sunday Night W 15-25
Monday Morning W 20-30
Monday Afternoon W 15-25
East South Ridgeline Winds (mph)
Sunday Evening W 5-15
Sunday Night WSW 10-20
Monday Morning WSW 10-20
Monday Afternoon W 5-15
Mt. Hood Ridgeline Winds (mph)
Sunday Evening WNW 10-20
Sunday Night WSW 25-35
Monday Morning WSW 25-35
Monday Afternoon W 20-30

Issued: 4:07 PM PST Sunday, December 5, 2021

Extended Weather Synopsis

Temperatures cool as a broad trough with sustained westerly flow moves into the region Tuesday night with increasing light to moderate rain and snow. Westerly flow, additional cooling, and significant mountain snowfall can be expected through Thursday.

Extended Snow Level (ft)

Tuesday Night Wednesday Wednesday Night Thursday
West North 4000' 2000' 500' 500'
Snoqualmie Pass 4500' 2000' 1000' 1000'
Mt. Hood 6000' 3000' 2000' 2000'
West North Elevation
Tuesday Night 4000'
Wednesday 2000'
Wednesday Night 500'
Thursday 500'
Snoqualmie Pass Elevation
Tuesday Night 4500'
Wednesday 2000'
Wednesday Night 1000'
Thursday 1000'
Mt. Hood Elevation
Tuesday Night 6000'
Wednesday 3000'
Wednesday Night 2000'
Thursday 2000'

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

Previous forecast from Dec 4, 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’.