Issued: 2:21 PM PST Saturday, December 11, 2021
by Robert Hahn

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

Weather Synopsis

We're locked into a cold, snowy pattern in the short term with increasing snow to water ratios throughout the period.

A potent cold front passed through the Cascades by early Saturday afternoon. Temperatures are gradually cooling behind the front and most mountain areas should be experiencing snowfall by Saturday evening. Moderate winds with just enough moisture should wring out mountain-induced snowfall, heavy at times through the overnight hours.

This weather pattern features a series of more organized bands of snowfall or "comma clouds" aiming for the Pacific Northwest. The first such band of snow showers crosses the Olympics on Saturday afternoon and should move across the Cascades through the early evening hours. The second stronger comma cloud should arrive in the early morning hours on Sunday. A third comma cloud may arrive early Monday morning. In between each event, expect lighter snowfall. Each comma cloud could feature 2-3" per hour snowfall rates and a period of stronger southerly winds before winds revert to a more southwesterly direction.

Sunday night and Monday, snow shower activity becomes lighter and a light E flow develops through the mountain gaps.

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
Saturday Night Moderate snow showers, locally intense, and heavier overnight. Cool.
Sunday Light to moderate snow showers, locally intense. Cool.
Saturday Night Moderate snow showers heavy at times, increasing overnight. Cool. Moderate ridgeline winds with strong gusts overnight.
Sunday Light to moderate snow showers, locally intense. Cool.
Saturday Night Moderate snow showers heavy at times, increasing overnight. Cool.
Sunday Light to moderate snow showers, locally intense. Cool.
Saturday Night Moderate snow showers Crystal and White Pass; heavy snow showers at Paradise. Showers increasing overnight.
Sunday Light to moderate snow showers, locally intense. Cool.
Saturday Night Moderate snow showers, increasing overnight. Light to occasionally moderate W wind at the Pass.
Sunday Light snow showers, locally intense. Cool.
Saturday Night Moderate snow showers, increasing overnight. Light to occasionally moderate W wind at the Pass.
Sunday Light snow showers, locally intense. Cool.
Saturday Night Light to moderate snow showers.
Sunday Light snow showers, locally intense. Cool.
Saturday Night Light snow showers. Decreasing moderate to strong ridgeline winds.
Sunday Light snow showers, locally intense. Cool.
Saturday Night Light to moderate snow showers.
Sunday Light snow showers, locally intense. Cool.
Saturday Night Moderate to heavy snow showers. Strong ridgeline winds.
Sunday Decreasing light to moderate snow showers, locally intense. Cool. Decreasing moderate to strong ridgeline winds.

Issued: 2:21 PM PST Saturday, December 11, 2021

Precipitation (in)

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

Issued: 2:21 PM PST Saturday, December 11, 2021

Snow Level (ft)

Saturday Evening Saturday Night Sunday Morning Sunday Afternoon Sunday Evening* Sunday Night* Monday Morning* Monday Afternoon*
Olympics 1000' 1000' 500' 1000' 1000' 1000' 1000' 1500'
West North 1500' 0 500' 1000' 500' 500' 0 1000'
West Central 2000' 1000' 1000' 1000' 1000' 500' 500' 1500'
West South 2000' 1000' 1000' 1500' 1000' 1000' 1000' 2000'
Stevens Pass 2500' 1000' 1000' 1000' 1000' 0 0 1500'
Snoqualmie Pass 2500' 1000' 1000' 1000' 1000' 500' 1000' 2000'
East North 2000' 0 0 1000' 500' 0 500' 1000'
East Central 2500' 500' 1000' 1000' 500' 500' 500' 1500'
East South 3000' 1500' 1000' 1500' 1000' 1500' 1500' 2500'
Mt. Hood 3000' 2500' 1500' 2000' 1500' 1500' 1500' 2500'
Olympics Elevation
Saturday Evening 1000'
Saturday Night 1000'
Sunday Morning 500'
Sunday Afternoon 1000'
Sunday Evening* 1000'
Sunday Night* 1000'
Monday Morning* 1000'
Monday Afternoon* 1500'
West North Elevation
Saturday Evening 1500'
Saturday Night 0'
Sunday Morning 500'
Sunday Afternoon 1000'
Sunday Evening* 500'
Sunday Night* 500'
Monday Morning* 0'
Monday Afternoon* 1000'
West Central Elevation
Saturday Evening 2000'
Saturday Night 1000'
Sunday Morning 1000'
Sunday Afternoon 1000'
Sunday Evening* 1000'
Sunday Night* 500'
Monday Morning* 500'
Monday Afternoon* 1500'
West South Elevation
Saturday Evening 2000'
Saturday Night 1000'
Sunday Morning 1000'
Sunday Afternoon 1500'
Sunday Evening* 1000'
Sunday Night* 1000'
Monday Morning* 1000'
Monday Afternoon* 2000'
Stevens Pass Elevation
Saturday Evening 2500'
Saturday Night 1000'
Sunday Morning 1000'
Sunday Afternoon 1000'
Sunday Evening* 1000'
Sunday Night* 0'
Monday Morning* 0'
Monday Afternoon* 1500'
Snoqualmie Pass Elevation
Saturday Evening 2500'
Saturday Night 1000'
Sunday Morning 1000'
Sunday Afternoon 1000'
Sunday Evening* 1000'
Sunday Night* 500'
Monday Morning* 1000'
Monday Afternoon* 2000'
East North Elevation
Saturday Evening 2000'
Saturday Night 0'
Sunday Morning 0'
Sunday Afternoon 1000'
Sunday Evening* 500'
Sunday Night* 0'
Monday Morning* 500'
Monday Afternoon* 1000'
East Central Elevation
Saturday Evening 2500'
Saturday Night 500'
Sunday Morning 1000'
Sunday Afternoon 1000'
Sunday Evening* 500'
Sunday Night* 500'
Monday Morning* 500'
Monday Afternoon* 1500'
East South Elevation
Saturday Evening 3000'
Saturday Night 1500'
Sunday Morning 1000'
Sunday Afternoon 1500'
Sunday Evening* 1000'
Sunday Night* 1500'
Monday Morning* 1500'
Monday Afternoon* 2500'
Mt. Hood Elevation
Saturday Evening 3000'
Saturday Night 2500'
Sunday Morning 1500'
Sunday Afternoon 2000'
Sunday Evening* 1500'
Sunday Night* 1500'
Monday Morning* 1500'
Monday Afternoon* 2500'

Issued: 2:21 PM PST Saturday, December 11, 2021

5000' Temperatures (°F)

Saturday Night Sunday
Max / Min Max / Min
Olympics 21 / 15 20 / 16
West North 21 / 14 20 / 16
West Central 23 / 18 21 / 17
West South 25 / 19 23 / 18
Stevens Pass 23 / 16 22 / 16
Snoqualmie Pass 21 / 18 22 / 17
East North 24 / 13 20 / 14
East Central 24 / 16 22 / 16
East South 25 / 17 24 / 16
Mt. Hood 27 / 21 25 / 18
Olympics 5000' Temperature Forecast
(Max / Min)
Saturday Night 21 / 15
Sunday 20 / 16
West North 5000' Temperature Forecast
(Max / Min)
Saturday Night 21 / 14
Sunday 20 / 16
West Central 5000' Temperature Forecast
(Max / Min)
Saturday Night 23 / 18
Sunday 21 / 17
West South 5000' Temperature Forecast
(Max / Min)
Saturday Night 25 / 19
Sunday 23 / 18
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Saturday Night 23 / 16
Sunday 22 / 16
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Saturday Night 21 / 18
Sunday 22 / 17
East North 5000' Temperature Forecast
(Max / Min)
Saturday Night 24 / 13
Sunday 20 / 14
East Central 5000' Temperature Forecast
(Max / Min)
Saturday Night 24 / 16
Sunday 22 / 16
East South 5000' Temperature Forecast
(Max / Min)
Saturday Night 25 / 17
Sunday 24 / 16
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Saturday Night 27 / 21
Sunday 25 / 18

Issued: 2:21 PM PST Saturday, December 11, 2021

Ridgeline Winds (mph)

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

Issued: 2:21 PM PST Saturday, December 11, 2021

Extended Weather Synopsis

The extended forecast looks less active, but remains cold. The deep trough moves onshore Monday night and Tuesday with the trough's energy headed toward California. Our mountains should squeeze out some low-density, light snow showers. The first trough shifts east just in time for an open low to slide down the coast. This might bring some light snow to the southern part of our forecast region by Wednesday afternoon.

 

Extended Snow Level (ft)

Monday Night* Tuesday Tuesday Night Wednesday
West North 0 1000' 500' 1000'
Snoqualmie Pass 500' 1000' 500' 1000'
Mt. Hood 1000' 1000' 500' 1500'
West North Elevation
Monday Night* 0'
Tuesday 1000'
Tuesday Night 500'
Wednesday 1000'
Snoqualmie Pass Elevation
Monday Night* 500'
Tuesday 1000'
Tuesday Night 500'
Wednesday 1000'
Mt. Hood Elevation
Monday Night* 1000'
Tuesday 1000'
Tuesday Night 500'
Wednesday 1500'

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

Previous forecast from Dec 11, 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’.