Issued: 2:11 PM PST Monday, February 22, 2021
by Robert Hahn

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

Weather Synopsis

Unusually dangerous avalanche conditions exist in the mountains. Please check the avalanche forecast before traveling to or recreating in the mountains.

A cold front moving from NW to SE provides a cutoff from the milder air and heavy rain/snow associated with our multi-day atmospheric river event. This front should pass through Snoqualmie Pass shortly after 2 PM and should be through Mt. Hood by around 7 PM.  Expect precipitation rates of 0.1-0.25" per hour for Mt. Hood prior to 7 PM. Very strong downslope winds continue in favored areas along the east slopes of the Cascades. Expect temperatures to continue to cool rapidly at upper elevations and more slowly at lower elevations behind the front. Our attention shifts to convergence zone bands forming rapidly behind the front and currently aimed at the Mountain Loop as of 2 PM on Monday. These bands will shift southward towards the highway 2 and I-90 corridors Monday night. Expect lighter snow showers outside of convergence bands with locally very intense snowfall rates in sharp convergence bands. As temperatures drop and snow-water ratios increase, locations receiving prolonged convergence may pick up more than a foot of snow. Favored locations include western parts of the Cascades East Central zone.

Models indicate a northward shift (toward the North Cascades) of the shower and convergence activity Tuesday morning as a shortwave trough approaches. Multiple convergence bands drop southward as the shortwave moves through Tuesday afternoon. Expect more convective showers with graupel or locally intense snowfall rates likely even in isolated showers, but particularly in convergence bands.

Strong to very strong down-slope and W winds over the Cascade Crest and major mountain gaps winds should gradually ease Monday night into Tuesday morning but should increase slightly Tuesday afternoon with the shortwave feature.

Strong convergence continues in the Central Cascades Wednesday evening before a trough digging slightly to the east of the region reduces or ends shower activity as flow switches NNW overnight. Snow levels should drop to sea level in most areas.

On Wednesday, after a chilly and mostly sunny start to the day with a short-lived ridge building into the region, high and mid-level clouds increase throughout the day ahead of another system.

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
Monday Night Light snow showers.
Tuesday Light convective snow showers.
Monday Night Light to occasionally moderate snow showers, heaviest southern part.
Tuesday Light to occasionally moderate convective snow showers, heaviest southern part.
Monday Night Moderate rain and snow showers, heavy in convergence bands. Moderate to strong ridgeline winds. Rapidly lowering snow levels.
Tuesday Moderate convective snow showers, heavy in convergence bands. Moderate to strong ridgeline winds.
Monday Night Moderate rain and snow showers at Paradise and White Pass; light at Crystal. Rapidly lowering snow levels. Decreasing strong ridgeline winds at White Pass and near the Cascade Crest.
Tuesday Moderate convective snow showers at Paradise and White Pass; light at Crystal. Moderate to strong ridgeline winds at White Pass and near the Cascade Crest.
Monday Night Moderate snow showers with heavy convergence likely at times. Light to moderate W winds at the Pass. Moderate to strong ridgeline winds.
Tuesday Moderate convective snow showers with heavy convergence likely at times. Moderate to strong ridgeline winds.
Monday Night Moderate rain and snow showers with heavy convergence likely. Snow levels rapidly dropping below the Pass. Moderate W winds at the Pass. Strong ridgeline winds decreasing into the moderate range.
Tuesday Moderate convective snow showers with heavy convergence likely at times, particularly during the afternoon. Moderate to strong ridgeline winds.
Monday Night Light snow showers. Stong ridgeline winds in the evening gradually easing. Strong ridgeline winds decreasing.
Tuesday Light, but locally intense snow showers. Moderate to strong ridgeline winds. Ridgeline winds increasing into the moderate to strong range.
Monday Night Moderate rain and snow showers, locally heavy in convergence bands; strong winds, western part. Light rain and snow showers with strong to very strong ridgeline winds, eastern part.
Tuesday Light convective snow showers. Moderate ridgeline winds western part; strong ridgeline winds eastern part.
Monday Night Light to moderate rain and snow showers changing to all snow showers. Moderate to strong ridgeline winds.
Tuesday Light convective snow showers.
Monday Night Heavy rain and snow in the early tapering to light to moderate snow showers. Strong ridgeline winds.
Tuesday Light convective snow showers. Strong ridgeline winds.

Precipitation (in)

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

Snow Level (ft)

Monday Evening Monday Night Tuesday Morning Tuesday Afternoon Tuesday Evening Tuesday Night Wednesday Morning Wednesday Afternoon
Olympics 2500' 2000' 1500' 1500' 1000' 0 0 1500'
West North 2500' 1500' 500' 1500' 500' 0 0 1500'
West Central 3000' 2000' 1000' 1500' 1000' 0 0 1500'
West South 3500' 2000' 1500' 2000' 1500' 0 0 2500'
Stevens Pass 3500' 2000' 1000' 2000' 1000' 0 0 2000'
Snoqualmie Pass 3500' 2000' 1500' 2000' 1500' 0 0 2000'
East North 3000' 1500' 0 2000' 1000' 0 0 2000'
East Central 3500' 2000' 1500' 2000' 1500' 0 0 2500'
East South 4000' 2000' 1500' 2500' 1500' 500' 0 2500'
Mt. Hood 5000' 2500' 1500' 2000' 2000' 1000' 500' 2500'
Olympics Elevation
Monday Evening 2500'
Monday Night 2000'
Tuesday Morning 1500'
Tuesday Afternoon 1500'
Tuesday Evening 1000'
Tuesday Night 0'
Wednesday Morning 0'
Wednesday Afternoon 1500'
West North Elevation
Monday Evening 2500'
Monday Night 1500'
Tuesday Morning 500'
Tuesday Afternoon 1500'
Tuesday Evening 500'
Tuesday Night 0'
Wednesday Morning 0'
Wednesday Afternoon 1500'
West Central Elevation
Monday Evening 3000'
Monday Night 2000'
Tuesday Morning 1000'
Tuesday Afternoon 1500'
Tuesday Evening 1000'
Tuesday Night 0'
Wednesday Morning 0'
Wednesday Afternoon 1500'
West South Elevation
Monday Evening 3500'
Monday Night 2000'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Tuesday Evening 1500'
Tuesday Night 0'
Wednesday Morning 0'
Wednesday Afternoon 2500'
Stevens Pass Elevation
Monday Evening 3500'
Monday Night 2000'
Tuesday Morning 1000'
Tuesday Afternoon 2000'
Tuesday Evening 1000'
Tuesday Night 0'
Wednesday Morning 0'
Wednesday Afternoon 2000'
Snoqualmie Pass Elevation
Monday Evening 3500'
Monday Night 2000'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Tuesday Evening 1500'
Tuesday Night 0'
Wednesday Morning 0'
Wednesday Afternoon 2000'
East North Elevation
Monday Evening 3000'
Monday Night 1500'
Tuesday Morning 0'
Tuesday Afternoon 2000'
Tuesday Evening 1000'
Tuesday Night 0'
Wednesday Morning 0'
Wednesday Afternoon 2000'
East Central Elevation
Monday Evening 3500'
Monday Night 2000'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Tuesday Evening 1500'
Tuesday Night 0'
Wednesday Morning 0'
Wednesday Afternoon 2500'
East South Elevation
Monday Evening 4000'
Monday Night 2000'
Tuesday Morning 1500'
Tuesday Afternoon 2500'
Tuesday Evening 1500'
Tuesday Night 500'
Wednesday Morning 0'
Wednesday Afternoon 2500'
Mt. Hood Elevation
Monday Evening 5000'
Monday Night 2500'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Tuesday Evening 2000'
Tuesday Night 1000'
Wednesday Morning 500'
Wednesday Afternoon 2500'

5000' Temperatures (°F)

Monday Night Tuesday
Max / Min Max / Min
Olympics 23 / 19 /
West North 24 / 19 /
West Central 25 / 19 /
West South 30 / 20 /
Stevens Pass 27 / 19 /
Snoqualmie Pass 28 / 20 /
East North 24 / 18 /
East Central 29 / 18 /
East South 32 / 19 /
Mt. Hood 33 / 20 /
Olympics 5000' Temperature Forecast
(Max / Min)
Monday 4pm - 4am 23 / 19
Tuesday 4am - 4pm /
West North 5000' Temperature Forecast
(Max / Min)
Monday 4pm - 4am 24 / 19
Tuesday 4am - 4pm /
West Central 5000' Temperature Forecast
(Max / Min)
Monday 4pm - 4am 25 / 19
Tuesday 4am - 4pm /
West South 5000' Temperature Forecast
(Max / Min)
Monday 4pm - 4am 30 / 20
Tuesday 4am - 4pm /
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Monday 4pm - 4am 27 / 19
Tuesday 4am - 4pm /
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Monday 4pm - 4am 28 / 20
Tuesday 4am - 4pm /
East North 5000' Temperature Forecast
(Max / Min)
Monday 4pm - 4am 24 / 18
Tuesday 4am - 4pm /
East Central 5000' Temperature Forecast
(Max / Min)
Monday 4pm - 4am 29 / 18
Tuesday 4am - 4pm /
East South 5000' Temperature Forecast
(Max / Min)
Monday 4pm - 4am 32 / 19
Tuesday 4am - 4pm /
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Monday 4pm - 4am 33 / 20
Tuesday 4am - 4pm /

Ridgeline Winds (mph)

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

Extended Weather Synopsis

Light to moderate mountain snow arrives late Wednesday night as a potent shortwave trough with an associated cold front arriving from the NW. A brief period of moderate to strong WSW winds turns W Thursday morning with the cold frontal passage. These winds should efficiently churn out moderate to heavy snow changing to showers on Thursday.  More moderate to heavy snow showers are expected as winds turn NW on Thursday night before snow gradually easing as a deeper trough moves over and then east of our region on Friday. Temperatures should stay slightly below average with snow levels 1000-2500 ft throughout the extended forecast period.

Extended Snow Level (ft)

Wednesday Night Thursday Thursday Night Friday
West North 1000' 1000' 1500' 1000'
Snoqualmie Pass 1500' 1500' 1500' 1500'
Mt. Hood 2000' 2500' 2000' 2000'
West North Elevation
Wednesday Night 1000'
Thursday 1000'
Thursday Night 1500'
Friday 1000'
Snoqualmie Pass Elevation
Wednesday Night 1500'
Thursday 1500'
Thursday Night 1500'
Friday 1500'
Mt. Hood Elevation
Wednesday Night 2000'
Thursday 2500'
Thursday Night 2000'
Friday 2000'

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

Previous forecast from Feb 22, 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’.

Updated Mountain Weather Zone Name Changes – December 2020