Issued: 2:23 PM PST Tuesday, January 12, 2021
by Robert Hahn

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

Weather Synopsis

Two of the first three waves of a major atmospheric river event have already impacted the Pacific Northwest. The water amounts are already very impressive across the region. Over the past 48 hours, we've seen 3-4" of water equivalent at Paradise, Snoqualmie, and Crystal, while Mt. Baker takes the crown with over 6" of water. Much of this came as snow at mid and higher elevations through Monday night, but a warm front raised the snow level above all major ski area bases early Tuesday.

Our region is in a slight lull on Tuesday afternoon with moderate to heavy (rather than heavy to very heavy) rain and high elevation snowfall rates between waves. The third and final wave arrives Tuesday evening with rain/snow and snow levels both peaking in the late evening or overnight hours as a strong cold front crosses the region from west to east in the early morning horus, ultimately providing a relief valve to the subtropical firehose. We're expecting another 1-2.5" in many areas with continued strong spillover to the lee of the Cascades. SW winds will also peak in the moderate to strong range before switching westerly and increasing through the passes and along the east slopes of the Cascades behind the front. There's very little cold air left and Washington pass remains the only area with pass-level snow. Washington Pass could see a mix or brief changeover to rain at pass level with the frontal passage. However, the front will also bring strong cooling.

Wednesday should be much cooler with rain and snow showers changing to all snow as moderate to strong W flow brings the colder air mass into the region rapidly. Light to moderate snow showers should decrease and focus on the central Washington Cascades, where they will linger into the afternoon. Stevens Pass and the mountain loop may see locally intense snowfall with convergence bands.

A fairly large ridge builds offshore late Wednesday and moves onshore Wednesday night through Thursday, bringing a cold night followed by significant warming west of the crest. Freezing levels could reach 11000 ft for Mt. Hood. Another cold pool will develop east of the Cascade Crest and E flow should keep the passes relatively cool.

Weather Forecast

Use dropdown to select your zone
Tuesday Night Heavy rain and high elevation snow peaking in the late evening. Precipitation becoming showery with cooling in the early morning hours. Ridgeline winds increasing into the moderate to strong range.
Wednesday A chance of light snow showers early in the day, then becoming mostly cloudy.

Precipitation (in)

Tuesday Night Wednesday Wednesday Night Thursday
4 pm - 4 am 4 am - 4 pm 4 pm - 4 am 4 am - 4 pm
Hurricane Ridge 0.75 -1.00 LT 0.10 0 0
Mt Baker Ski Area 2.00 0.25 0 0
Mt. Loop - Barlow Pass 2.00 - 2.50 0.25 - 0.50 LT 0.10 0
Stevens Pass 1.50 0.25 - 0.50 LT 0.10 0
Snoqualmie Pass 2.00 0.25 LT 0.10 0
Crystal Mt 1.00 LT 0.25 0 0
Paradise 1.50 - 2.00 0.25 0 0
White Pass 1.50 0.25 0 0
Washington Pass 1.50 0.25 0 0
Mission Ridge 0.75 LT 0.25 0 0
Salmon la Sac - Gallagher Head 1.50 0.25 LT 0.10 0
Tieton River - Darland Mt. 1.00 LT 0.25 0 0
Mt Hood Meadows 1.50 0.25 - 0.50 0 0
Timberline 1.50 0.50 0 0
Hurricane Ridge Precipitation (in)
Tuesday Night 0.75 -1.00
Wednesday LT 0.10
Wednesday Night 0
Thursday 0
Mt Baker Ski Area Precipitation (in)
Tuesday Night 2.00
Wednesday 0.25
Wednesday Night 0
Thursday 0
Mt. Loop - Barlow Pass Precipitation (in)
Tuesday Night 2.00 - 2.50
Wednesday 0.25 - 0.50
Wednesday Night LT 0.10
Thursday 0
Stevens Pass Precipitation (in)
Tuesday Night 1.50
Wednesday 0.25 - 0.50
Wednesday Night LT 0.10
Thursday 0
Snoqualmie Pass Precipitation (in)
Tuesday Night 2.00
Wednesday 0.25
Wednesday Night LT 0.10
Thursday 0
Crystal Mt Precipitation (in)
Tuesday Night 1.00
Wednesday LT 0.25
Wednesday Night 0
Thursday 0
Paradise Precipitation (in)
Tuesday Night 1.50 - 2.00
Wednesday 0.25
Wednesday Night 0
Thursday 0
White Pass Precipitation (in)
Tuesday Night 1.50
Wednesday 0.25
Wednesday Night 0
Thursday 0
Washington Pass Precipitation (in)
Tuesday Night 1.50
Wednesday 0.25
Wednesday Night 0
Thursday 0
Mission Ridge Precipitation (in)
Tuesday Night 0.75
Wednesday LT 0.25
Wednesday Night 0
Thursday 0
Salmon la Sac - Gallagher Head Precipitation (in)
Tuesday Night 1.50
Wednesday 0.25
Wednesday Night LT 0.10
Thursday 0
Tieton River - Darland Mt. Precipitation (in)
Tuesday Night 1.00
Wednesday LT 0.25
Wednesday Night 0
Thursday 0
Mt Hood Meadows Precipitation (in)
Tuesday Night 1.50
Wednesday 0.25 - 0.50
Wednesday Night 0
Thursday 0
Timberline Precipitation (in)
Tuesday Night 1.50
Wednesday 0.50
Wednesday Night 0
Thursday 0

Snow Level (ft)

Tuesday Evening * Tuesday Night Wednesday Morning Wednesday Afternoon Wednesday Evening Wednesday Night * Thursday Morning * Thursday Afternoon *
Olympics 6500' 6000' 2500' 2500' 2500' 3000' 6000' 9000'
West North 6000' 6000' 2500' 2000' 1500' 2000' 2000' 5000'
West Central 6500' 6500' 3000' 2000' 2000' 2000' 300' 6500'
West South 7000' 7000' 3000' 2500' 2000' 2500' 4500' 9000'
Stevens Pass 6500' 6500' 3000' 2000' 2000' 2000' 2500' 3000'
Snoqualmie Pass 7000' 7000' 3000' 2000' 2500' 2000' 3000' 3500'
East North 5000' 5000' 3000' 2000' 1500' 1500' 2000' 3000'
East Central 6500' 7000' 3000' 2000' 2500' 2000' 3000' 3500'
East South 7500' 7500' 3500' 2500' 2500' 3000' 3000' 5000'
Mt. Hood 8500' 8000' 3500' 3000' 3000' 5500' 7500' 11500'
Olympics Elevation
Tuesday Evening * 6500'
Tuesday Night 6000'
Wednesday Morning 2500'
Wednesday Afternoon 2500'
Wednesday Evening 2500'
Wednesday Night * 3000'
Thursday Morning * 6000'
Thursday Afternoon * 9000'
West North Elevation
Tuesday Evening * 6000'
Tuesday Night 6000'
Wednesday Morning 2500'
Wednesday Afternoon 2000'
Wednesday Evening 1500'
Wednesday Night * 2000'
Thursday Morning * 2000'
Thursday Afternoon * 5000'
West Central Elevation
Tuesday Evening * 6500'
Tuesday Night 6500'
Wednesday Morning 3000'
Wednesday Afternoon 2000'
Wednesday Evening 2000'
Wednesday Night * 2000'
Thursday Morning * 300'
Thursday Afternoon * 6500'
West South Elevation
Tuesday Evening * 7000'
Tuesday Night 7000'
Wednesday Morning 3000'
Wednesday Afternoon 2500'
Wednesday Evening 2000'
Wednesday Night * 2500'
Thursday Morning * 4500'
Thursday Afternoon * 9000'
Stevens Pass Elevation
Tuesday Evening * 6500'
Tuesday Night 6500'
Wednesday Morning 3000'
Wednesday Afternoon 2000'
Wednesday Evening 2000'
Wednesday Night * 2000'
Thursday Morning * 2500'
Thursday Afternoon * 3000'
Snoqualmie Pass Elevation
Tuesday Evening * 7000'
Tuesday Night 7000'
Wednesday Morning 3000'
Wednesday Afternoon 2000'
Wednesday Evening 2500'
Wednesday Night * 2000'
Thursday Morning * 3000'
Thursday Afternoon * 3500'
East North Elevation
Tuesday Evening * 5000'
Tuesday Night 5000'
Wednesday Morning 3000'
Wednesday Afternoon 2000'
Wednesday Evening 1500'
Wednesday Night * 1500'
Thursday Morning * 2000'
Thursday Afternoon * 3000'
East Central Elevation
Tuesday Evening * 6500'
Tuesday Night 7000'
Wednesday Morning 3000'
Wednesday Afternoon 2000'
Wednesday Evening 2500'
Wednesday Night * 2000'
Thursday Morning * 3000'
Thursday Afternoon * 3500'
East South Elevation
Tuesday Evening * 7500'
Tuesday Night 7500'
Wednesday Morning 3500'
Wednesday Afternoon 2500'
Wednesday Evening 2500'
Wednesday Night * 3000'
Thursday Morning * 3000'
Thursday Afternoon * 5000'
Mt. Hood Elevation
Tuesday Evening * 8500'
Tuesday Night 8000'
Wednesday Morning 3500'
Wednesday Afternoon 3000'
Wednesday Evening 3000'
Wednesday Night * 5500'
Thursday Morning * 7500'
Thursday Afternoon * 11500'

5000' Temperatures (°F)

Tuesday Night Wednesday
Max / Min Max / Min
Olympics 37 / 26 26 / 23
West North 36 / 29 29 / 23
West Central 37 / 30 30 / 24
West South 38 / 31 31 / 24
Stevens Pass 36 / 30 30 / 24
Snoqualmie Pass 37 / 31 31 / 24
East North 33 / 31 31 / 23
East Central 35 / 31 31 / 25
East South 38 / 31 31 / 25
Mt. Hood 41 / 31 31 / 27
Olympics 5000' Temperature Forecast
(Max / Min)
Tuesday 4pm - 4am 37 / 26
Wednesday 4am - 4pm 26 / 23
West North 5000' Temperature Forecast
(Max / Min)
Tuesday 4pm - 4am 36 / 29
Wednesday 4am - 4pm 29 / 23
West Central 5000' Temperature Forecast
(Max / Min)
Tuesday 4pm - 4am 37 / 30
Wednesday 4am - 4pm 30 / 24
West South 5000' Temperature Forecast
(Max / Min)
Tuesday 4pm - 4am 38 / 31
Wednesday 4am - 4pm 31 / 24
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Tuesday 4pm - 4am 36 / 30
Wednesday 4am - 4pm 30 / 24
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Tuesday 4pm - 4am 37 / 31
Wednesday 4am - 4pm 31 / 24
East North 5000' Temperature Forecast
(Max / Min)
Tuesday 4pm - 4am 33 / 31
Wednesday 4am - 4pm 31 / 23
East Central 5000' Temperature Forecast
(Max / Min)
Tuesday 4pm - 4am 35 / 31
Wednesday 4am - 4pm 31 / 25
East South 5000' Temperature Forecast
(Max / Min)
Tuesday 4pm - 4am 38 / 31
Wednesday 4am - 4pm 31 / 25
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Tuesday 4pm - 4am 41 / 31
Wednesday 4am - 4pm 31 / 27

Ridgeline Winds (mph)

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

Extended Weather Synopsis

A weakening trailing end of a cold front keeps the high pressure progressing eastward Thursday evening and should bring a round of mostly light rain and snow to the region Thursday night into Friday morning. W flow behind the front should keep a slight chance of shower activity in the forecast for Friday afternoon and evening. A ridge building into the region from the offshore waters should clear skies out later Friday night and Saturday morning. However, clouds should increase Saturday afternoon ahead of another relatively weak frontal system poised to move onshore Saturday night.

Extended Snow Level (ft)

Thursday Night * Friday Friday Night Saturday *
West North 5500' 4000' 3500' 3500'
Snoqualmie Pass 5500' 5000' 4500' 4500'
Mt. Hood 9000' 7000' 6000' 8500'
West North Elevation
Thursday Night * 5500'
Friday 4000'
Friday Night 3500'
Saturday * 3500'
Snoqualmie Pass Elevation
Thursday Night * 5500'
Friday 5000'
Friday Night 4500'
Saturday * 4500'
Mt. Hood Elevation
Thursday Night * 9000'
Friday 7000'
Friday Night 6000'
Saturday * 8500'

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

Previous forecast from Jan 12, 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’.