Issued: 2:05 PM PST Wednesday, December 15, 2021
by Robert Hahn

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

Weather Synopsis

The closed low impacting the region with some light snow on Wednesday afternoon moves onshore around the Columbia River mouth Wednesday evening. Light snow becomes increasingly patchy and decreases overnight from a northern extent around highway 2, southward.

The region mostly dries out late Wednesday night and early Thursday morning before a shortwave trough moving down from British Columbia taps into just enough coastal moisture for some light snow showers and weak convergence activity focused towards the central Washington Cascades.

Wednesday night through Thursday, our mountains should expect 1-3" of snow accumulation with up to 6" in the Mt. Hood area.

Snow shower activity tapers to flurries Thursday night as a weak ridge centered off the coast edges into the area. The ridge should bring fair weather on Friday with filtered sunshine in the morning and thickening high clouds in the afternoon.

Temperatures remain cold and relatively steady throughout the forecast period, with highs in the 20s and lows dropping into the 10s in many locations.

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
Wednesday Night Snow flurries possible during the evening hours, then partial clearing overnight.
Thursday A chance of light snow showers in the morning. Then, decreasing clouds and partly sunny conditions in the afternoon.
Wednesday Night Mostly cloudy in the evening with light snow possible overnight. Cold.
Thursday Light snow showers.
Wednesday Night Mostly cloudy in the evening with light snow possible overnight. Cold.
Thursday Light snow showers.
Wednesday Night Cloudy. Cold. Strong ridgeline winds the Crystal area becoming moderate and decreasing.
Thursday Cloudy with light snow showers developing in the afternoon.
Wednesday Night Light snow is possible at times. Light to moderate E winds become light at the Pass.
Thursday Increasing light snow showers. Light E wind shifting W early and increasing.
Wednesday Night Light snow at times. Moderate E winds become light at the Pass.
Thursday Increasing light snow showers. Light E wind shifting W early and increasing.
Wednesday Night Mostly cloudy.
Thursday Mostly cloudy with a chance of snow flurries.
Wednesday Night Light snow tapering during the evening, then becoming cloudy with flurries.
Thursday Mostly cloudy with an increasing chance of light snow showers in the afternoon.
Wednesday Night Light snow tapering during the evening, then becoming cloudy with flurries.
Thursday Partly cloudy with an increasing chance of light snow showers near the Cascade Crest in the afternoon.
Wednesday Night Light to occasionally moderate snow.
Thursday Light snow showers.

Precipitation (in)

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

Snow Level (ft)

Wednesday Evening* Wednesday Night* Thursday Morning Thursday Afternoon Thursday Evening* Thursday Night* Friday Morning* Friday Afternoon*
Olympics 2500' 1500' 500' 2000' 2000' 1500' 500' 2500'
West North 1500' 1000' 500' 1000' 1000' 1000' 1000' 2000'
West Central 1500' 500' 500' 1500' 1000' 1000' 1000' 2500'
West South 500' 500' 500' 2000' 1500' 500' 1000' 3000'
Stevens Pass 0 0 0 1500' 1000' 500' 0 2500'
Snoqualmie Pass 0 0 0 1500' 1000' 500' 500' 2500'
East North 500' 0 0 1000' 1000' 500' 0 1500'
East Central 0 0 0 1500' 1000' 1000' 500' 2500'
East South 500' 0 500' 2000' 1500' 1000' 1500' 3000'
Mt. Hood 1500' 1000' 1500' 2500' 2000' 1500' 2000' 3500'
Olympics Elevation
Wednesday Evening* 2500'
Wednesday Night* 1500'
Thursday Morning 500'
Thursday Afternoon 2000'
Thursday Evening* 2000'
Thursday Night* 1500'
Friday Morning* 500'
Friday Afternoon* 2500'
West North Elevation
Wednesday Evening* 1500'
Wednesday Night* 1000'
Thursday Morning 500'
Thursday Afternoon 1000'
Thursday Evening* 1000'
Thursday Night* 1000'
Friday Morning* 1000'
Friday Afternoon* 2000'
West Central Elevation
Wednesday Evening* 1500'
Wednesday Night* 500'
Thursday Morning 500'
Thursday Afternoon 1500'
Thursday Evening* 1000'
Thursday Night* 1000'
Friday Morning* 1000'
Friday Afternoon* 2500'
West South Elevation
Wednesday Evening* 500'
Wednesday Night* 500'
Thursday Morning 500'
Thursday Afternoon 2000'
Thursday Evening* 1500'
Thursday Night* 500'
Friday Morning* 1000'
Friday Afternoon* 3000'
Stevens Pass Elevation
Wednesday Evening* 0'
Wednesday Night* 0'
Thursday Morning 0'
Thursday Afternoon 1500'
Thursday Evening* 1000'
Thursday Night* 500'
Friday Morning* 0'
Friday Afternoon* 2500'
Snoqualmie Pass Elevation
Wednesday Evening* 0'
Wednesday Night* 0'
Thursday Morning 0'
Thursday Afternoon 1500'
Thursday Evening* 1000'
Thursday Night* 500'
Friday Morning* 500'
Friday Afternoon* 2500'
East North Elevation
Wednesday Evening* 500'
Wednesday Night* 0'
Thursday Morning 0'
Thursday Afternoon 1000'
Thursday Evening* 1000'
Thursday Night* 500'
Friday Morning* 0'
Friday Afternoon* 1500'
East Central Elevation
Wednesday Evening* 0'
Wednesday Night* 0'
Thursday Morning 0'
Thursday Afternoon 1500'
Thursday Evening* 1000'
Thursday Night* 1000'
Friday Morning* 500'
Friday Afternoon* 2500'
East South Elevation
Wednesday Evening* 500'
Wednesday Night* 0'
Thursday Morning 500'
Thursday Afternoon 2000'
Thursday Evening* 1500'
Thursday Night* 1000'
Friday Morning* 1500'
Friday Afternoon* 3000'
Mt. Hood Elevation
Wednesday Evening* 1500'
Wednesday Night* 1000'
Thursday Morning 1500'
Thursday Afternoon 2500'
Thursday Evening* 2000'
Thursday Night* 1500'
Friday Morning* 2000'
Friday Afternoon* 3500'

5000' Temperatures (°F)

Wednesday Night Thursday
Max / Min Max / Min
Olympics 24 / 19 24 / 18
West North 22 / 18 22 / 17
West Central 19 / 17 23 / 18
West South 21 / 18 24 / 19
Stevens Pass 18 / 13 23 / 18
Snoqualmie Pass 20 / 17 23 / 20
East North 15 / 13 22 / 12
East Central 18 / 13 25 / 15
East South 18 / 14 25 / 17
Mt. Hood 26 / 24 26 / 22
Olympics 5000' Temperature Forecast
(Max / Min)
Wednesday Night 24 / 19
Thursday 24 / 18
West North 5000' Temperature Forecast
(Max / Min)
Wednesday Night 22 / 18
Thursday 22 / 17
West Central 5000' Temperature Forecast
(Max / Min)
Wednesday Night 19 / 17
Thursday 23 / 18
West South 5000' Temperature Forecast
(Max / Min)
Wednesday Night 21 / 18
Thursday 24 / 19
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Wednesday Night 18 / 13
Thursday 23 / 18
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Wednesday Night 20 / 17
Thursday 23 / 20
East North 5000' Temperature Forecast
(Max / Min)
Wednesday Night 15 / 13
Thursday 22 / 12
East Central 5000' Temperature Forecast
(Max / Min)
Wednesday Night 18 / 13
Thursday 25 / 15
East South 5000' Temperature Forecast
(Max / Min)
Wednesday Night 18 / 14
Thursday 25 / 17
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Wednesday Night 26 / 24
Thursday 26 / 22

Ridgeline Winds (mph)

Wednesday Evening Wednesday Night Thursday Morning Thursday Afternoon
Olympics S 5-15 SSE 0-10 WNW 0-10 WNW 5-15
West North SSE 5-15 SSW 0-10 W 0-10 NW 5-15
West Central ESE 15-25 SSE 5-15 W 5-15 WNW 10-20
West South SE 15-25 SW 0-10 W 0-10 W 5-15
Stevens Pass ESE 10-20 SE 0-10 W 5-15 WNW 10-20
Snoqualmie Pass ESE 15-25 SE 0-10 W 5-15 WNW 15-25
East North SE 10-20 S 5-15 W 5-15 WNW 10-20
East Central SE 15-25 WSW 0-10 WNW 10-20 WNW 15-25
East South SE 5-15 WSW 0-10 WNW 5-15 WNW 10-20
Mt. Hood SW 10-20 WSW 10-20 WSW 5-15 W 15-25
Olympics Ridgeline Winds (mph)
Wednesday Evening S 5-15
Wednesday Night SSE 0-10
Thursday Morning WNW 0-10
Thursday Afternoon WNW 5-15
West North Ridgeline Winds (mph)
Wednesday Evening SSE 5-15
Wednesday Night SSW 0-10
Thursday Morning W 0-10
Thursday Afternoon NW 5-15
West Central Ridgeline Winds (mph)
Wednesday Evening ESE 15-25
Wednesday Night SSE 5-15
Thursday Morning W 5-15
Thursday Afternoon WNW 10-20
West South Ridgeline Winds (mph)
Wednesday Evening SE 15-25
Wednesday Night SW 0-10
Thursday Morning W 0-10
Thursday Afternoon W 5-15
Stevens Pass Ridgeline Winds (mph)
Wednesday Evening ESE 10-20
Wednesday Night SE 0-10
Thursday Morning W 5-15
Thursday Afternoon WNW 10-20
Snoqualmie Pass Ridgeline Winds (mph)
Wednesday Evening ESE 15-25
Wednesday Night SE 0-10
Thursday Morning W 5-15
Thursday Afternoon WNW 15-25
East North Ridgeline Winds (mph)
Wednesday Evening SE 10-20
Wednesday Night S 5-15
Thursday Morning W 5-15
Thursday Afternoon WNW 10-20
East Central Ridgeline Winds (mph)
Wednesday Evening SE 15-25
Wednesday Night WSW 0-10
Thursday Morning WNW 10-20
Thursday Afternoon WNW 15-25
East South Ridgeline Winds (mph)
Wednesday Evening SE 5-15
Wednesday Night WSW 0-10
Thursday Morning WNW 5-15
Thursday Afternoon WNW 10-20
Mt. Hood Ridgeline Winds (mph)
Wednesday Evening SW 10-20
Wednesday Night WSW 10-20
Thursday Morning WSW 5-15
Thursday Afternoon W 15-25

Extended Weather Synopsis

A significant storm system begins to impact northern Washington state on Friday night with some light snowfall, but most of the warm frontal precipitation lfits northward into Canada. As the trailing cold front drops ESE, snowfall should pick up, particularly later Friday night. The heaviest rain and snow arrives Saturday night ahead of a strong cold front passing trough the Cascades by Sunday morning. Warming in southern parts of the forecast region should change Crystal and Mt. Hood ski area bases to rain on Saturday, but cold air pooled east of the Cascade Crest likely keeps the central Cascade Passes primarily snow. Some frontal precipitation may continue near Mt. Hood on Sunday as the cold front stalls, but trough moving onshore over Washington State should bring significant cooling and mostly light snow shower activity.

Extended Snow Level (ft)

Friday Night* Saturday * Saturday Night* Sunday
West North 1000' 2500' 3500' 1500'
Snoqualmie Pass 1000' 2000' 3000' 2000'
Mt. Hood 2500' 6500' 6000' 3000'
West North Elevation
Friday Night* 1000'
Saturday * 2500'
Saturday Night* 3500'
Sunday 1500'
Snoqualmie Pass Elevation
Friday Night* 1000'
Saturday * 2000'
Saturday Night* 3000'
Sunday 2000'
Mt. Hood Elevation
Friday Night* 2500'
Saturday * 6500'
Saturday Night* 6000'
Sunday 3000'

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

Previous forecast from Dec 15, 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’.