Issued: 2:05 PM PST Friday, December 31, 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

As of early Friday afternoon, northern areas of the forecast area have largely dried out in the late December sun while further south, low clouds in NW flow have hung tough along with light snow showers. The cold upper trough that has been a fixture over the West Coast for much of the last week will finally start to shift east overnight.  High to mid-clouds from an advancing Pacific frontal system in the Gulf of Alaska will stream over the area later tonight, thinning out over the southern Washington Cascades and Mt Hood.  Light snow along the southern edge of the warm front will develop over the Olympics and northwest Cascades Saturday afternoon, although the central Cascades may see some light flurries. For areas near and west of the Cascade crest and the Olympics and Mt Hood, temperatures will moderate in the upper teens and 20s, while east of the crest, temperatures will remain quite chilly. The frontal boundary may shift back to the north Saturday night as the parent low pressure system digs south along the B.C. coastline, keeping light precipitation aimed at the same areas.

The frontal system will finally push southwards during the Sunday with heavy snow developing for the Olympics and northwest Cascades. While light to moderate snow will develop in other areas on Sunday, look for strong to extreme southerly winds for the Olympics and west slopes of the Cascades before the heaviest precipitation arrives. Snow levels will slowly rise on Sunday along the west slopes of the Cascades, Olympics and Mt. Hood. Strong offshore gradients will drive very cold air through the Cascade Passes in the form of strong east winds and there may be areas of freezing rain west of the Cascade Passes Sunday afternoon or night. It looks to be an exciting start to 2022 - Happy New Year from the team at NWAC!

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
Friday Night Mostly cloudy in the evening, becoming cloudy overnight.
Saturday Cloudy with periods of very light snow.
Friday Night Mostly cloudy in the evening, becoming cloudy overnight. Chance of light snow late.
Saturday Cloudy with periods of very light snow.
Friday Night Mostly clear in the evening, then increasing high clouds overnight.
Saturday Cloudy. A few flurries in the afternoon.
Friday Night Mostly clear in the evening, then increasing high clouds overnight.
Saturday Mostly cloudy with periods of high and mid clouds.
Friday Night Mostly clear in the evening, then increasing high clouds overnight. Moderate east winds at Pass level.
Saturday Cloudy. A few flurries in the afternoon. Light east winds at Pass level becoming light to moderate in the afternoon.
Friday Night Mostly clear in the evening, then increasing high clouds overnight. Moderate east winds at Pass level.
Saturday Cloudy. A few flurries in the afternoon. Light east winds at Pass level becoming light to moderate in the afternoon.
Friday Night Mostly clear in the evening, then increasing high clouds overnight.
Saturday Cloudy with a chance of very light snow.
Friday Night Mostly clear in the evening, then increasing high clouds overnight.
Saturday Mostly cloudy with periods of high and mid clouds.
Friday Night Mostly clear in the evening, then increasing high clouds late.
Saturday Partly to mostly cloudy with periods of high clouds.
Friday Night Mostly clear.
Saturday Partly cloudy with periods of high clouds.

Precipitation (in)

Friday Night Saturday Saturday Night Sunday
4 pm - 4 am 4 am - 4 pm 4 pm - 4 am 4 am - 4 pm
Hurricane Ridge 0 LT 0.10 LT 0.10 1.00
Mt Baker Ski Area 0 LT 0.10 LT 0.10 0.75 -1.00
Mt. Loop - Barlow Pass 0 0 LT 0.10 0.25 - 0.50
Stevens Pass 0 0 0 LT 0.25
Snoqualmie Pass 0 0 0 LT 0.25
Crystal Mt 0 0 0 LT 0.25
Paradise 0 0 0 LT 0.25
White Pass 0 0 0 LT 0.10
Washington Pass 0 LT 0.10 0 0.25
Mission Ridge 0 0 0 LT 0.10
Salmon la Sac - Gallagher Head 0 0 0 LT 0.10
Tieton River - Darland Mt. 0 0 0 LT 0.10
Mt Hood Meadows 0 0 0 LT 0.10
Timberline 0 0 0 LT 0.10
Hurricane Ridge Precipitation (in)
Friday Night 0
Saturday LT 0.10
Saturday Night LT 0.10
Sunday 1.00
Mt Baker Ski Area Precipitation (in)
Friday Night 0
Saturday LT 0.10
Saturday Night LT 0.10
Sunday 0.75 -1.00
Mt. Loop - Barlow Pass Precipitation (in)
Friday Night 0
Saturday 0
Saturday Night LT 0.10
Sunday 0.25 - 0.50
Stevens Pass Precipitation (in)
Friday Night 0
Saturday 0
Saturday Night 0
Sunday LT 0.25
Snoqualmie Pass Precipitation (in)
Friday Night 0
Saturday 0
Saturday Night 0
Sunday LT 0.25
Crystal Mt Precipitation (in)
Friday Night 0
Saturday 0
Saturday Night 0
Sunday LT 0.25
Paradise Precipitation (in)
Friday Night 0
Saturday 0
Saturday Night 0
Sunday LT 0.25
White Pass Precipitation (in)
Friday Night 0
Saturday 0
Saturday Night 0
Sunday LT 0.10
Washington Pass Precipitation (in)
Friday Night 0
Saturday LT 0.10
Saturday Night 0
Sunday 0.25
Mission Ridge Precipitation (in)
Friday Night 0
Saturday 0
Saturday Night 0
Sunday LT 0.10
Salmon la Sac - Gallagher Head Precipitation (in)
Friday Night 0
Saturday 0
Saturday Night 0
Sunday LT 0.10
Tieton River - Darland Mt. Precipitation (in)
Friday Night 0
Saturday 0
Saturday Night 0
Sunday LT 0.10
Mt Hood Meadows Precipitation (in)
Friday Night 0
Saturday 0
Saturday Night 0
Sunday LT 0.10
Timberline Precipitation (in)
Friday Night 0
Saturday 0
Saturday Night 0
Sunday LT 0.10

Snow Level (ft)

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

5000' Temperatures (°F)

Friday Night Saturday
Max / Min Max / Min
Olympics 17 / 12 28 / 18
West North 13 / 9 22 / 10
West Central 14 / 10 24 / 11
West South 15 / 8 25 / 12
Stevens Pass 15 / 8 20 / 12
Snoqualmie Pass 14 / 9 19 / 11
East North 10 / -3 15 / 2
East Central 11 / 4 19 / 7
East South 12 / 2 21 / 9
Mt. Hood 15 / 10 28 / 15
Olympics 5000' Temperature Forecast
(Max / Min)
Friday Night 17 / 12
Saturday 28 / 18
West North 5000' Temperature Forecast
(Max / Min)
Friday Night 13 / 9
Saturday 22 / 10
West Central 5000' Temperature Forecast
(Max / Min)
Friday Night 14 / 10
Saturday 24 / 11
West South 5000' Temperature Forecast
(Max / Min)
Friday Night 15 / 8
Saturday 25 / 12
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Friday Night 15 / 8
Saturday 20 / 12
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Friday Night 14 / 9
Saturday 19 / 11
East North 5000' Temperature Forecast
(Max / Min)
Friday Night 10 / -3
Saturday 15 / 2
East Central 5000' Temperature Forecast
(Max / Min)
Friday Night 11 / 4
Saturday 19 / 7
East South 5000' Temperature Forecast
(Max / Min)
Friday Night 12 / 2
Saturday 21 / 9
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Friday Night 15 / 10
Saturday 28 / 15

Ridgeline Winds (mph)

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

Extended Weather Synopsis

The frontal boundary and heavy precipitation will push south Sunday night, with stormy conditions for all areas. The same boundary may stall around northern Oregon on Monday, delivering heavy precipitation along with rising snow levels. Most of Washington will be in cool post-frontal showers by Monday morning with additional snowfall accumulations and blustery ridgeline winds out the west likely. Things should be interesting for the remainder of the week with several systems on tap. Next up, a low-pressure system heading for northern Oregon on Tuesday may produce the heaviest precipitation for the Mt Hood area and southern/central Washington Cascades.  

Extended Snow Level (ft)

Sunday Night* Monday Monday Night Tuesday *
West North 0 500' 0 0
Snoqualmie Pass 0 500' 0 0
Mt. Hood 4000' 2000' 1000' 3000'
West North Elevation
Sunday Night* 0'
Monday 500'
Monday Night 0'
Tuesday * 0'
Snoqualmie Pass Elevation
Sunday Night* 0'
Monday 500'
Monday Night 0'
Tuesday * 0'
Mt. Hood Elevation
Sunday Night* 4000'
Monday 2000'
Monday Night 1000'
Tuesday * 3000'

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

Previous forecast from Dec 31, 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’.