Issued: 7:09 AM PST Friday, December 11, 2020
by Robert Hahn

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

Weather Synopsis

A broad upper low moved into the region on Thursday night. Many areas picked up 1-4" of snow overnight. The low continues to spin light snow showers into our mountains as it transits SE across the area on Friday, bringing generally light snow shower activity, steady but cool temperatures, and light winds to Washington State. Mt. Hood should a bit more wind and snow, but that snow has been slower to materialize than expected. Models continue to indicate a band of moderate snow impacting the Mt. Hood area in the late afternoon through evening hours.

The low moves east of the area by late evening on Friday, turning flow N and NE, cutting off the moisture and the snow shower activity. Expect partly to mostly clear skies arriving after midnight along with cold temperatures and light winds. 

On Saturday, a shortwave ridge transits the region. The region should see mostly clear skies with some low clouds or fog in the lowlands in the morning and cool temperatures. Clouds will increase from west to east as a system slated to arrive late Saturday night starts spreading clouds into the region. E flow will also increase through the passes and across the Cascade Crest and southerly winds will pick up aloft. Winds could reach the moderate range late in the day.

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 Mostly cloudy with a chance of light snow showers. Cool. Light winds.
Friday Night Upslope snow flurries in the evening, then partial clearing. Cold. Light winds.
Friday Decreasing light snow showers. Cool. Light winds.
Friday Night Partly cloudy in the evening, then mostly clear after midnight. Cold. Light winds.
Friday Decreasing light snow showers. Cool. Light winds.
Friday Night Partly cloudy in the evening, then mostly clear after midnight. Cold. Light winds.
Friday Light snow showers. Cool. Light winds.
Friday Night Mostly cloudy in the evening with a few snow showers in the evening, then partially clearing after midnight. Cold. Light winds.
Friday Decreasing light snow showers. Cool. Light winds. Light W wind through the pass.
Friday Night Partly cloudy in the evening, then mostly clear after midnight. Cold. Light and variable pass-level and ridgeline winds becoming light easterly.
Friday Light snow showers. Cool. Light ridgeline winds with moderate gusts. Light W wind through the pass.
Friday Night Partly cloudy in the evening, then mostly clear after midnight. Cold. Light and variable pass-level and ridgeline winds becoming light easterly.
Friday Mostly cloudy with a chance of snow showers. Cool. Light winds.
Friday Night Mostly cloudy in the evening with a few snow showers in the evening, then becoming mostly clear after midnight. Cold. Light winds.
Friday Light snow showers. Cool. Light winds.
Friday Night Mostly cloudy in the evening with a few upslope snow showers in the evening, then mostly clearing after midnight. Cold. Light winds.
Friday Increasing light snow showers. Cool. Light winds.
Friday Night Mostly cloudy in the evening with a few snow showers in the evening, then partially clearing after midnight. Cold. Light winds.
Friday Moderate snow showers becoming moderate snow in the late afternoon. Cool. Decreasing light to moderate ridgeline winds.
Friday Night Moderate snow in the early evening tapering and ending by midnight with partial clearing thereafter. Cool. Light ridgeline winds.

Precipitation (in)

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

Snow Level (ft)

Friday Morning Friday Afternoon Friday Evening Friday Night* Saturday Morning* Saturday Afternoon*
Olympics 2000' 2000' 1500' 2500' 5000' 4500'
West North 2000' 2000' 1500' 2000' 2000' 3000'
West Central 2000' 2000' 1000' 2000' 2000' 2500'
West South 2000' 2500' 1000' 2500' 2500' 3500'
Stevens Pass 1500' 2000' 1500' 2000' 1500' 2000'
Snoqualmie Pass 1500' 2000' 1000' 2000' 2000' 2500'
East North 1500' 2000' 1000' 2000' 1000' 2000'
East Central 1000' 2500' 1500' 1500' 1500' 2000'
East South 1000' 2500' 1500' 2000' 2000' 3000'
Mt. Hood 1500' 2500' 2000' 3000' 3000' 4000'
Olympics Elevation
Friday Morning 2000'
Friday Afternoon 2000'
Friday Evening 1500'
Friday Night* 2500'
Saturday Morning* 5000'
Saturday Afternoon* 4500'
West North Elevation
Friday Morning 2000'
Friday Afternoon 2000'
Friday Evening 1500'
Friday Night* 2000'
Saturday Morning* 2000'
Saturday Afternoon* 3000'
West Central Elevation
Friday Morning 2000'
Friday Afternoon 2000'
Friday Evening 1000'
Friday Night* 2000'
Saturday Morning* 2000'
Saturday Afternoon* 2500'
West South Elevation
Friday Morning 2000'
Friday Afternoon 2500'
Friday Evening 1000'
Friday Night* 2500'
Saturday Morning* 2500'
Saturday Afternoon* 3500'
Stevens Pass Elevation
Friday Morning 1500'
Friday Afternoon 2000'
Friday Evening 1500'
Friday Night* 2000'
Saturday Morning* 1500'
Saturday Afternoon* 2000'
Snoqualmie Pass Elevation
Friday Morning 1500'
Friday Afternoon 2000'
Friday Evening 1000'
Friday Night* 2000'
Saturday Morning* 2000'
Saturday Afternoon* 2500'
East North Elevation
Friday Morning 1500'
Friday Afternoon 2000'
Friday Evening 1000'
Friday Night* 2000'
Saturday Morning* 1000'
Saturday Afternoon* 2000'
East Central Elevation
Friday Morning 1000'
Friday Afternoon 2500'
Friday Evening 1500'
Friday Night* 1500'
Saturday Morning* 1500'
Saturday Afternoon* 2000'
East South Elevation
Friday Morning 1000'
Friday Afternoon 2500'
Friday Evening 1500'
Friday Night* 2000'
Saturday Morning* 2000'
Saturday Afternoon* 3000'
Mt. Hood Elevation
Friday Morning 1500'
Friday Afternoon 2500'
Friday Evening 2000'
Friday Night* 3000'
Saturday Morning* 3000'
Saturday Afternoon* 4000'

5000' Temperatures (°F)

Friday Friday Night
Max / Min Max / Min
Olympics 24 / 17 20 / 19
West North 23 / 19 18 / 16
West Central 22 / 18 19 / 15
West South 24 / 17 19 / 17
Stevens Pass 24 / 18 18 / 15
Snoqualmie Pass 22 / 18 17 / 15
East North 25 / 19 19 / 14
East Central 24 / 18 17 / 15
East South 26 / 17 19 / 15
Mt. Hood 27 / 21 23 / 17
Olympics 5000' Temperature Forecast
(Max / Min)
Friday 24 / 17
Friday Night 20 / 19
West North 5000' Temperature Forecast
(Max / Min)
Friday 23 / 19
Friday Night 18 / 16
West Central 5000' Temperature Forecast
(Max / Min)
Friday 22 / 18
Friday Night 19 / 15
West South 5000' Temperature Forecast
(Max / Min)
Friday 24 / 17
Friday Night 19 / 17
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Friday 24 / 18
Friday Night 18 / 15
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Friday 22 / 18
Friday Night 17 / 15
East North 5000' Temperature Forecast
(Max / Min)
Friday 25 / 19
Friday Night 19 / 14
East Central 5000' Temperature Forecast
(Max / Min)
Friday 24 / 18
Friday Night 17 / 15
East South 5000' Temperature Forecast
(Max / Min)
Friday 26 / 17
Friday Night 19 / 15
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Friday 27 / 21
Friday Night 23 / 17

Ridgeline Winds (mph)

Friday Morning Friday Afternoon Friday Evening Friday Night
Olympics SW 0-10 NE 0-10 ENE 0-10 ENE 0-10
West North SSW 0-10 NNW 0-10 NE 5-15 ENE 0-10
West Central SW 5-15 WNW 0-10 NNE 0-10 E 0-10
West South WSW 0-10 SW 0-10 N 5-15 ENE 0-10
Stevens Pass WSW 5-15 WNW 0-10 NE 0-10 E 5-15
Snoqualmie Pass W 5-15 WNW 5-15 NNE 0-10 E 0-10
East North WSW 5-15 NW 0-10 NNE 5-15 SSW 0-10
East Central W 5-15 WNW 0-10 NNE 5-15 ENE 5-15
East South WSW 5-15 W 0-10 NNE 0-10 ENE 5-15
Mt. Hood WSW 10-20 WSW 10-20 WNW 0-10 E 5-15
Olympics Ridgeline Winds (mph)
Friday Morning SW 0-10
Friday Afternoon NE 0-10
Friday Evening ENE 0-10
Friday Night ENE 0-10
West North Ridgeline Winds (mph)
Friday Morning SSW 0-10
Friday Afternoon NNW 0-10
Friday Evening NE 5-15
Friday Night ENE 0-10
West Central Ridgeline Winds (mph)
Friday Morning SW 5-15
Friday Afternoon WNW 0-10
Friday Evening NNE 0-10
Friday Night E 0-10
West South Ridgeline Winds (mph)
Friday Morning WSW 0-10
Friday Afternoon SW 0-10
Friday Evening N 5-15
Friday Night ENE 0-10
Stevens Pass Ridgeline Winds (mph)
Friday Morning WSW 5-15
Friday Afternoon WNW 0-10
Friday Evening NE 0-10
Friday Night E 5-15
Snoqualmie Pass Ridgeline Winds (mph)
Friday Morning W 5-15
Friday Afternoon WNW 5-15
Friday Evening NNE 0-10
Friday Night E 0-10
East North Ridgeline Winds (mph)
Friday Morning WSW 5-15
Friday Afternoon NW 0-10
Friday Evening NNE 5-15
Friday Night SSW 0-10
East Central Ridgeline Winds (mph)
Friday Morning W 5-15
Friday Afternoon WNW 0-10
Friday Evening NNE 5-15
Friday Night ENE 5-15
East South Ridgeline Winds (mph)
Friday Morning WSW 5-15
Friday Afternoon W 0-10
Friday Evening NNE 0-10
Friday Night ENE 5-15
Mt. Hood Ridgeline Winds (mph)
Friday Morning WSW 10-20
Friday Afternoon WSW 10-20
Friday Evening WNW 0-10
Friday Night E 5-15

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

Previous forecast from Dec 10, 2020

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’.