Issued: 6:52 AM PST Thursday, December 30, 2021
by Dallas Glass

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

Weather Synopsis

Conditions appear quite stormy across most of our mountain locations this morning. A fast-moving disturbance has spread a band of moderate to heavy snow over the Olympics and Cascades. This line of precipitation should quickly swing south focussing the bulk of the precipitation from about I90 to Mt Hood. As it does so, locations to the north should see steady snow turn to showers and wind speeds significantly decrease. For locations further south, periods of heavy snow and strong winds could linger into the afternoon. The weather looks particularly stormy for Mt Hood where heavy snow and very strong to extreme winds could create challenging travel conditions with poor visibility throughout the day. By late afternoon only a few showers and much lighter winds will be all that's left of this quick storm. 

Overnight a few stray showers could linger particularly in the southern Cascades. As much drier air and northerly winds enter the region we should begin to see slow clearing from North to South. This should return very cold temperatures to the mountains with lows in the teens or even single digits. While most locations begin to see a break in the weather, Mt Hood could remain quite stormy with continued snowfall and strong winds. 

A high-pressure ridge pushes over the region by Friday morning finally putting an end to any leftover snow showers and helping the skies continue to clear. Some low-level clouds in the mountain valleys and pass in the morning should quickly give way to a very nice, cold, and sunny 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
Thursday Snow in the morning becoming cloudy. Possible sun breaks in the afternoon. Moderate winds decreasing.
Thursday Night Mostly cloudy and cold.
Thursday Snow in the morning becoming cloudy by lunchtime. Possible sun breaks late in the day. Moderate winds quickly decreasing and becoming more northerly.
Thursday Night Mostly cloudy becoming mostly clear. Cold.
Thursday Snow, heaviest in the morning with isolated snow showers in the afternoon. A weak Puget Sound Convergence Zone is possible. Moderate winds significantly decreasing.
Thursday Night Mostly cloudy with some clearing overnight. Cold.
Thursday Stormy with moderate to heavy snow particularly in the morning. Moderate to strong W winds decreasing slightly in the afternoon.
Thursday Night Scattered snow showers particularly near Mt St Helens and Mt Adams. Cloudy and cold. Generally light winds.
Thursday Snow, heaviest in the morning. Becoming cloudy with snow showers in the afternoon. Light east flow developing at Pass level. A week Puget Sound Convergence Zone is possible.
Thursday Night Cloudy and cold. Isolated snow showers possible in the evening. Light westerly winds.
Thursday Snow, heaviest in the morning. Becoming cloudy with snow showers in the afternoon. Light east flow developing at Pass level. A week Puget Sound Convergence Zone is possible.
Thursday Night Cloudy and cold. Isolated snow showers possible in the evening. Light to moderate westerly winds.
Thursday Cloudy with scattered snow showers in the morning. Possible sun breaks in the afternoon. Winds significantly decreasing.
Thursday Night Mostly cloudy becoming mostly clear. Low clouds in the valleys. Cold.
Thursday Cloudy with snow showers heaviest near the crest. Moderate to strong W winds decreasing in the afternoon.
Thursday Night Mostly cloudy becoming mostly clear with low-level clouds in the mountain valleys and passes. A few flurries possible. Cold.
Thursday Stormy, particularly near the crest. Strong W winds decreasing slightly in the afternoon.
Thursday Night Cloudy with isolated snow showers. Cold Light to moderate NW winds.
Thursday Stormy with periods of heavy snowfall, very strong West winds, and poor visibility.
Thursday Night Cloudy with moderate snow showers possible. Strong W winds decreasing slightly.

Precipitation (in)

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

Snow Level (ft)

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

5000' Temperatures (°F)

Thursday Thursday Night
Max / Min Max / Min
Olympics 21 / 5 9 / 3
West North 15 / 8 10 / 3
West Central 18 / 15 14 / 5
West South 22 / 11 16 / 7
Stevens Pass 18 / 10 13 / 5
Snoqualmie Pass 19 / 12 16 / 8
East North 13 / 5 11 / -5
East Central 17 / 13 12 / 2
East South 22 / 15 15 / 9
Mt. Hood 23 / 17 22 / 15
Olympics 5000' Temperature Forecast
(Max / Min)
Thursday 21 / 5
Thursday Night 9 / 3
West North 5000' Temperature Forecast
(Max / Min)
Thursday 15 / 8
Thursday Night 10 / 3
West Central 5000' Temperature Forecast
(Max / Min)
Thursday 18 / 15
Thursday Night 14 / 5
West South 5000' Temperature Forecast
(Max / Min)
Thursday 22 / 11
Thursday Night 16 / 7
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Thursday 18 / 10
Thursday Night 13 / 5
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Thursday 19 / 12
Thursday Night 16 / 8
East North 5000' Temperature Forecast
(Max / Min)
Thursday 13 / 5
Thursday Night 11 / -5
East Central 5000' Temperature Forecast
(Max / Min)
Thursday 17 / 13
Thursday Night 12 / 2
East South 5000' Temperature Forecast
(Max / Min)
Thursday 22 / 15
Thursday Night 15 / 9
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Thursday 23 / 17
Thursday Night 22 / 15

Ridgeline Winds (mph)

Thursday Morning Thursday Afternoon Thursday Evening Thursday Night
Olympics NW 10-20 NNW 0-10 NNW 5-15 NNW 5-15
West North S 10-20 NNE 0-10 NNE 0-10 NNE 5-15
West Central SW 10-20 VAR 0-10 W 5-15 NW 5-15
West South WSW 20-30 W 15-25 WNW 5-15 WNW 5-15
Stevens Pass SW 5-15 W 5-15 W 5-15 WNW 5-15
Snoqualmie Pass WSW 10-20 W 10-20 WNW 10-20 WNW 10-20
East North SW 5-15 NNE 0-10 NNW 0-10 NNW 5-15
East Central WSW 20-30 NW 5-15 NW 10-20 WSW 15-25
East South WSW 25-35 WNW 20-30 NW 10-20 NW 10-20
Mt. Hood W 40-55 W 35-50 W 30-40 W 25-35
Olympics Ridgeline Winds (mph)
Thursday Morning NW 10-20
Thursday Afternoon NNW 0-10
Thursday Evening NNW 5-15
Thursday Night NNW 5-15
West North Ridgeline Winds (mph)
Thursday Morning S 10-20
Thursday Afternoon NNE 0-10
Thursday Evening NNE 0-10
Thursday Night NNE 5-15
West Central Ridgeline Winds (mph)
Thursday Morning SW 10-20
Thursday Afternoon VAR 0-10
Thursday Evening W 5-15
Thursday Night NW 5-15
West South Ridgeline Winds (mph)
Thursday Morning WSW 20-30
Thursday Afternoon W 15-25
Thursday Evening WNW 5-15
Thursday Night WNW 5-15
Stevens Pass Ridgeline Winds (mph)
Thursday Morning SW 5-15
Thursday Afternoon W 5-15
Thursday Evening W 5-15
Thursday Night WNW 5-15
Snoqualmie Pass Ridgeline Winds (mph)
Thursday Morning WSW 10-20
Thursday Afternoon W 10-20
Thursday Evening WNW 10-20
Thursday Night WNW 10-20
East North Ridgeline Winds (mph)
Thursday Morning SW 5-15
Thursday Afternoon NNE 0-10
Thursday Evening NNW 0-10
Thursday Night NNW 5-15
East Central Ridgeline Winds (mph)
Thursday Morning WSW 20-30
Thursday Afternoon NW 5-15
Thursday Evening NW 10-20
Thursday Night WSW 15-25
East South Ridgeline Winds (mph)
Thursday Morning WSW 25-35
Thursday Afternoon WNW 20-30
Thursday Evening NW 10-20
Thursday Night NW 10-20
Mt. Hood Ridgeline Winds (mph)
Thursday Morning W 40-55
Thursday Afternoon W 35-50
Thursday Evening W 30-40
Thursday Night W 25-35

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

Previous forecast from Dec 29, 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’.