Issued: 7:24 AM PST Tuesday, January 12, 2021
by Robert Hahn

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

Weather Synopsis

An atmospheric river continues to bring very heavy rain and snow to the region. In the past 48 hours, Mt. Baker has picked up nearly 5" of water equivalent, while most other areas have picked up 1-3". E flow kept Snoqualmie Pass snow through the night, and the pass has picked up 20" of snow with temperatures hovering right at 32 degrees as of 7 AM. The moisture onslaught will continue throughout the day into the evening. A warm front crossing the region this morning will continue to push snow levels higher and gradually win the battle against the cooler east flow. We expect Snoqualmie to transition to rain at pass level during the mid-moring hours and the snow line to retreat quickly to higher elevations (6500 ft) by afternoon. Stevens should see the transition during mid-day or early afternoon hours. The forecast is particularly tricky because we don't expect a wind shift, so the cold pool east of the Cascade Crest has to erode enough that the east flow just isn't cool enough. That cooler air is dense and hard to move!

The moisture feed should focus most heavily from central Washington south to Mt. Hood, but Mt. Baker will still get plenty of water. 1-3" of water equivalent can be expected during daylight hours with moderate SW winds. A strong cold front should pass after midnight Tuesday night ends the atmospheric river and brings a rapid decrease in the heavy precipitation, but not before some of the heaviest precipitation rates are expected Tuesday evening. The frontal passage also comes with a cool-down and mid-elevations could see moderate to locally heavy snow showers and convergence by Wednesday morning.

Expect light to moderate snow showers decreasing on Wednesday with temperatures continuing to plummet with snow levels dropping to pass level or below.

Weather Forecast

Use dropdown to select your zone
Tuesday Heavy rain and high elevation snow. Strong wind gusts at ridgelines.
Tuesday Night Very heavy rain and high elevation snow transitioning to rain and snow showers after midnight. Strong wind gusts at ridgelines.

Precipitation (in)

Tuesday Tuesday Night Wednesday
4 am - 4 pm 4 pm - 4 am 4 am - 4 pm
Hurricane Ridge 0.50 0.75 LT 0.10
Mt Baker Ski Area 1.00 - 1.50 1.50 LT 0.25
Mt. Loop - Barlow Pass 2.00 2.00 0.25
Stevens Pass 1.00 - 1.50 1.50 0.25
Snoqualmie Pass 2.00 1.50 0.25
Crystal Mt 1.50 1.00 LT 0.25
Paradise 2.50 - 3.50 1.50 - 2.00 0.25
White Pass 1.50 1.50 0.25
Washington Pass 1.00 - 1.50 1.00 - 1.50 0.25
Mission Ridge 0.50 0.50 LT 0.10
Salmon la Sac - Gallagher Head 1.50 1.00 - 1.50 0.25
Tieton River - Darland Mt. 0.75 -1.00 1.00 LT 0.25
Mt Hood Meadows 2.00 2.00 0.25
Timberline 2.00 2.00 0.25
Hurricane Ridge Precipitation (in)
Tuesday 0.50
Tuesday Night 0.75
Wednesday LT 0.10
Mt Baker Ski Area Precipitation (in)
Tuesday 1.00 - 1.50
Tuesday Night 1.50
Wednesday LT 0.25
Mt. Loop - Barlow Pass Precipitation (in)
Tuesday 2.00
Tuesday Night 2.00
Wednesday 0.25
Stevens Pass Precipitation (in)
Tuesday 1.00 - 1.50
Tuesday Night 1.50
Wednesday 0.25
Snoqualmie Pass Precipitation (in)
Tuesday 2.00
Tuesday Night 1.50
Wednesday 0.25
Crystal Mt Precipitation (in)
Tuesday 1.50
Tuesday Night 1.00
Wednesday LT 0.25
Paradise Precipitation (in)
Tuesday 2.50 - 3.50
Tuesday Night 1.50 - 2.00
Wednesday 0.25
White Pass Precipitation (in)
Tuesday 1.50
Tuesday Night 1.50
Wednesday 0.25
Washington Pass Precipitation (in)
Tuesday 1.00 - 1.50
Tuesday Night 1.00 - 1.50
Wednesday 0.25
Mission Ridge Precipitation (in)
Tuesday 0.50
Tuesday Night 0.50
Wednesday LT 0.10
Salmon la Sac - Gallagher Head Precipitation (in)
Tuesday 1.50
Tuesday Night 1.00 - 1.50
Wednesday 0.25
Tieton River - Darland Mt. Precipitation (in)
Tuesday 0.75 -1.00
Tuesday Night 1.00
Wednesday LT 0.25
Mt Hood Meadows Precipitation (in)
Tuesday 2.00
Tuesday Night 2.00
Wednesday 0.25
Timberline Precipitation (in)
Tuesday 2.00
Tuesday Night 2.00
Wednesday 0.25

Snow Level (ft)

Tuesday Morning Tuesday Afternoon Tuesday Evening Tuesday Night Wednesday Morning Wednesday Afternoon
Olympics 7000' 6500' 6500' 5500' 2500' 2500'
West North 4500' 6000' 6000' 6000' 2500' 2000'
West Central 5500' 6000' 6500' 6000' 3000' 2000'
West South 6500' 6500' 7000' 7000' 3000' 2500'
Stevens Pass 3000' 6000' 6500' 6500' 3000' 2000'
Snoqualmie Pass 3500' 6500' 7000' 6500' 3000' 2000'
East North 2500' 3500' 4500' 5000' 3000' 1500'
East Central 3500' 6500' 6500' 6500' 3000' 2000'
East South 6500' 6500' 7500' 7000' 3500' 2500'
Mt. Hood 8000' 7500' 8000' 8000' 4000' 3000'
Olympics Elevation
Tuesday Morning 7000'
Tuesday Afternoon 6500'
Tuesday Evening 6500'
Tuesday Night 5500'
Wednesday Morning 2500'
Wednesday Afternoon 2500'
West North Elevation
Tuesday Morning 4500'
Tuesday Afternoon 6000'
Tuesday Evening 6000'
Tuesday Night 6000'
Wednesday Morning 2500'
Wednesday Afternoon 2000'
West Central Elevation
Tuesday Morning 5500'
Tuesday Afternoon 6000'
Tuesday Evening 6500'
Tuesday Night 6000'
Wednesday Morning 3000'
Wednesday Afternoon 2000'
West South Elevation
Tuesday Morning 6500'
Tuesday Afternoon 6500'
Tuesday Evening 7000'
Tuesday Night 7000'
Wednesday Morning 3000'
Wednesday Afternoon 2500'
Stevens Pass Elevation
Tuesday Morning 3000'
Tuesday Afternoon 6000'
Tuesday Evening 6500'
Tuesday Night 6500'
Wednesday Morning 3000'
Wednesday Afternoon 2000'
Snoqualmie Pass Elevation
Tuesday Morning 3500'
Tuesday Afternoon 6500'
Tuesday Evening 7000'
Tuesday Night 6500'
Wednesday Morning 3000'
Wednesday Afternoon 2000'
East North Elevation
Tuesday Morning 2500'
Tuesday Afternoon 3500'
Tuesday Evening 4500'
Tuesday Night 5000'
Wednesday Morning 3000'
Wednesday Afternoon 1500'
East Central Elevation
Tuesday Morning 3500'
Tuesday Afternoon 6500'
Tuesday Evening 6500'
Tuesday Night 6500'
Wednesday Morning 3000'
Wednesday Afternoon 2000'
East South Elevation
Tuesday Morning 6500'
Tuesday Afternoon 6500'
Tuesday Evening 7500'
Tuesday Night 7000'
Wednesday Morning 3500'
Wednesday Afternoon 2500'
Mt. Hood Elevation
Tuesday Morning 8000'
Tuesday Afternoon 7500'
Tuesday Evening 8000'
Tuesday Night 8000'
Wednesday Morning 4000'
Wednesday Afternoon 3000'

5000' Temperatures (°F)

Tuesday Tuesday Night
Max / Min Max / Min
Olympics 36 / 34 37 / 27
West North 35 / 31 36 / 29
West Central 36 / 33 37 / 30
West South 37 / 32 38 / 31
Stevens Pass 34 / 25 36 / 30
Snoqualmie Pass 35 / 25 37 / 31
East North 31 / 21 33 / 31
East Central 35 / 25 35 / 31
East South 35 / 30 38 / 31
Mt. Hood 42 / 38 41 / 32
Olympics 5000' Temperature Forecast
(Max / Min)
Tuesday 4am - 4pm 36 / 34
Tuesday 4pm - 4am 37 / 27
West North 5000' Temperature Forecast
(Max / Min)
Tuesday 4am - 4pm 35 / 31
Tuesday 4pm - 4am 36 / 29
West Central 5000' Temperature Forecast
(Max / Min)
Tuesday 4am - 4pm 36 / 33
Tuesday 4pm - 4am 37 / 30
West South 5000' Temperature Forecast
(Max / Min)
Tuesday 4am - 4pm 37 / 32
Tuesday 4pm - 4am 38 / 31
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Tuesday 4am - 4pm 34 / 25
Tuesday 4pm - 4am 36 / 30
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Tuesday 4am - 4pm 35 / 25
Tuesday 4pm - 4am 37 / 31
East North 5000' Temperature Forecast
(Max / Min)
Tuesday 4am - 4pm 31 / 21
Tuesday 4pm - 4am 33 / 31
East Central 5000' Temperature Forecast
(Max / Min)
Tuesday 4am - 4pm 35 / 25
Tuesday 4pm - 4am 35 / 31
East South 5000' Temperature Forecast
(Max / Min)
Tuesday 4am - 4pm 35 / 30
Tuesday 4pm - 4am 38 / 31
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Tuesday 4am - 4pm 42 / 38
Tuesday 4pm - 4am 41 / 32

Ridgeline Winds (mph)

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

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

Previous forecast from Jan 11, 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’.