Issued: 2:21 PM PST Sunday, February 21, 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 apex of an atmospheric event will occur Sunday night through Monday. Expect very heavy rain and snow as an approaching shortwave focuses the heaviest rain and snow on the mountains of northern Washington with very intense rain and snowfall (above 4000-4500 ft) from Snoqualmie Pass northward. The heaviest precipitation should move southward in the early morning hours on Monday. Very strong winds on the east slopes and through the major mountain gaps will peak late Sunday evening and shift southward by Monday morning. Warming should peak early Monday morning as a cold front moves through the region from NW to SE. Behind the front, expect decreasing snowfall and convergence banding to focus on the mountain loop area.

The frontal rain/snow band moves south of the region by Monday evening. Cooling and shower activity continues with heavy convergence bands over the central Cascades and passes overnight. Snow levels should drop to Snoqualmie pass level and lower by around midnight.

With a trough over the area, snow shower and convergence continues in the moderate to strong range for the west slopes of the Cascades on Tuesday with low snow levels and high snow water ratios.

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
Sunday Night Moderate rain and snow. Strong ridgeline wind gusts at times.
Monday Moderate snow ending and turning to light snow showers.
Sunday Night Very heavy rain and snow. Moderate to strong ridgeline winds.
Monday Heavy rain and snow early transitioning to light rain and snow showers by afternoon.
Sunday Night Very heavy rain and snow. Strong ridgeline winds.
Monday Very heavy rain and snow. Moderate ridgeline winds with strong gusts.
Sunday Night Light rain and snow in the early evening increasing to heavy at Paradise and White Pass, and light at Crystal. Strong ridgeline winds, very strong through the mountain gaps.
Monday Very heavy rain and snow at Paradise, heavy at White Pass, and moderate at Crystal. Moderate to strong ridgeline winds, strongest through the mountain gaps.
Sunday Night Very heavy rain and snow. Moderate to strong ridgeline winds. Moderate W wind at the Pass.
Monday Very heavy rain and snow.
Sunday Night Heavy heavy rain and snow. Strong ridgeline winds in the evening, then gradually decreasing. Moderate W wind at the Pass.
Monday Very heavy rain and snow. Moderate to strong ridgeline winds.
Sunday Night Very heavy rain and snow. Strong ridgeline winds.
Monday Moderate to heavy rain and snow decreasing to light to moderate showers. Moderate ridgeline winds with strong gusts.
Sunday Night Heavy rain and snow. Strong to very strong ridgeline winds. Very strong ridgeline winds in the evening, then gradually decreasing.
Monday Very heavy rain and snow relenting slightly late in the day. Strong ridgeline winds.
Sunday Night Light to moderate rain and snow. Moderate to strong ridgeline winds.
Monday Moderate to heavy rain and snow. Strong ridgeline wind gusts.
Sunday Night Light to moderate rain and snow. Strong to very strong ridgeline winds
Monday Very heavy rain and snow. Strong ridgeline winds.

Issued: 2:21 PM PST Sunday, February 21, 2021

Precipitation (in)

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

Issued: 2:21 PM PST Sunday, February 21, 2021

Snow Level (ft)

Sunday Evening Sunday Night Monday Morning Monday Afternoon Monday Evening Monday Night Tuesday Morning Tuesday Afternoon
Olympics 5000' 5500' 4500' 3500' 2000' 2000' 1500' 2000'
West North 4000' 4000' 4000' 3500' 2000' 1500' 1000' 1500'
West Central 4000' 4000' 4000' 4000' 2500' 1500' 1000' 1500'
West South 4500' 4500' 4500' 4500' 3000' 2000' 1500' 2000'
Stevens Pass 4000' 4000' 4000' 4000' 3000' 1500' 1500' 2000'
Snoqualmie Pass 4000' 4500' 4500' 4000' 3000' 2000' 1500' 2000'
East North 4500' 4500' 4500' 4000' 2500' 1500' 1000' 2000'
East Central 4500' 4500' 4500' 4500' 3000' 2000' 1500' 2000'
East South 4500' 5000' 5000' 5000' 3500' 2000' 2000' 2500'
Mt. Hood 4500' 4500' 5500' 5500' 4500' 2000' 2000' 2500'
Olympics Elevation
Sunday Evening 5000'
Sunday Night 5500'
Monday Morning 4500'
Monday Afternoon 3500'
Monday Evening 2000'
Monday Night 2000'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
West North Elevation
Sunday Evening 4000'
Sunday Night 4000'
Monday Morning 4000'
Monday Afternoon 3500'
Monday Evening 2000'
Monday Night 1500'
Tuesday Morning 1000'
Tuesday Afternoon 1500'
West Central Elevation
Sunday Evening 4000'
Sunday Night 4000'
Monday Morning 4000'
Monday Afternoon 4000'
Monday Evening 2500'
Monday Night 1500'
Tuesday Morning 1000'
Tuesday Afternoon 1500'
West South Elevation
Sunday Evening 4500'
Sunday Night 4500'
Monday Morning 4500'
Monday Afternoon 4500'
Monday Evening 3000'
Monday Night 2000'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Stevens Pass Elevation
Sunday Evening 4000'
Sunday Night 4000'
Monday Morning 4000'
Monday Afternoon 4000'
Monday Evening 3000'
Monday Night 1500'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Snoqualmie Pass Elevation
Sunday Evening 4000'
Sunday Night 4500'
Monday Morning 4500'
Monday Afternoon 4000'
Monday Evening 3000'
Monday Night 2000'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
East North Elevation
Sunday Evening 4500'
Sunday Night 4500'
Monday Morning 4500'
Monday Afternoon 4000'
Monday Evening 2500'
Monday Night 1500'
Tuesday Morning 1000'
Tuesday Afternoon 2000'
East Central Elevation
Sunday Evening 4500'
Sunday Night 4500'
Monday Morning 4500'
Monday Afternoon 4500'
Monday Evening 3000'
Monday Night 2000'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
East South Elevation
Sunday Evening 4500'
Sunday Night 5000'
Monday Morning 5000'
Monday Afternoon 5000'
Monday Evening 3500'
Monday Night 2000'
Tuesday Morning 2000'
Tuesday Afternoon 2500'
Mt. Hood Elevation
Sunday Evening 4500'
Sunday Night 4500'
Monday Morning 5500'
Monday Afternoon 5500'
Monday Evening 4500'
Monday Night 2000'
Tuesday Morning 2000'
Tuesday Afternoon 2500'

Issued: 2:21 PM PST Sunday, February 21, 2021

5000' Temperatures (°F)

Sunday Night Monday
Max / Min Max / Min
Olympics 32 / 31 32 / 25
West North 31 / 30 31 / 25
West Central 30 / 30 32 / 27
West South 32 / 30 32 / 31
Stevens Pass 31 / 30 32 / 30
Snoqualmie Pass 31 / 30 32 / 29
East North 31 / 30 33 / 27
East Central 31 / 30 32 / 30
East South 32 / 30 34 / 31
Mt. Hood 33 / 30 34 / 33
Olympics 5000' Temperature Forecast
(Max / Min)
Sunday Night 32 / 31
Monday 32 / 25
West North 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 30
Monday 31 / 25
West Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 30 / 30
Monday 32 / 27
West South 5000' Temperature Forecast
(Max / Min)
Sunday Night 32 / 30
Monday 32 / 31
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 30
Monday 32 / 30
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 30
Monday 32 / 29
East North 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 30
Monday 33 / 27
East Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 30
Monday 32 / 30
East South 5000' Temperature Forecast
(Max / Min)
Sunday Night 32 / 30
Monday 34 / 31
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Sunday Night 33 / 30
Monday 34 / 33

Issued: 2:21 PM PST Sunday, February 21, 2021

Ridgeline Winds (mph)

Sunday Evening Sunday Night Monday Morning Monday Afternoon
Olympics SW 20-30 SW 10-20 WSW 10-20 WSW 10-20
West North SW 25-35 WSW 20-30 WSW 15-25 W 20-30
West Central WSW 30-40 WSW 30-40 WSW 20-30 W 15-25
West South W 25-35 WSW 25-35 WSW 25-35 WSW 20-30
Stevens Pass WSW 30-40 WSW 25-35 WSW 20-30 WSW 20-30
Snoqualmie Pass W 30-40 W 20-30 W 20-30 W 25-35
East North WSW 30-40 WSW 25-35 WSW 20-30 W 25-35
East Central W 40-55 WSW 30-40 WSW 30-40 W 25-35
East South W 25-35 WSW 25-35 WSW 20-30 WSW 20-30
Mt. Hood WSW 35-50 WSW 30-40 WSW 30-40 WSW 30-40
Olympics Ridgeline Winds (mph)
Sunday Evening SW 20-30
Sunday Night SW 10-20
Monday Morning WSW 10-20
Monday Afternoon WSW 10-20
West North Ridgeline Winds (mph)
Sunday Evening SW 25-35
Sunday Night WSW 20-30
Monday Morning WSW 15-25
Monday Afternoon W 20-30
West Central Ridgeline Winds (mph)
Sunday Evening WSW 30-40
Sunday Night WSW 30-40
Monday Morning WSW 20-30
Monday Afternoon W 15-25
West South Ridgeline Winds (mph)
Sunday Evening W 25-35
Sunday Night WSW 25-35
Monday Morning WSW 25-35
Monday Afternoon WSW 20-30
Stevens Pass Ridgeline Winds (mph)
Sunday Evening WSW 30-40
Sunday Night WSW 25-35
Monday Morning WSW 20-30
Monday Afternoon WSW 20-30
Snoqualmie Pass Ridgeline Winds (mph)
Sunday Evening W 30-40
Sunday Night W 20-30
Monday Morning W 20-30
Monday Afternoon W 25-35
East North Ridgeline Winds (mph)
Sunday Evening WSW 30-40
Sunday Night WSW 25-35
Monday Morning WSW 20-30
Monday Afternoon W 25-35
East Central Ridgeline Winds (mph)
Sunday Evening W 40-55
Sunday Night WSW 30-40
Monday Morning WSW 30-40
Monday Afternoon W 25-35
East South Ridgeline Winds (mph)
Sunday Evening W 25-35
Sunday Night WSW 25-35
Monday Morning WSW 20-30
Monday Afternoon WSW 20-30
Mt. Hood Ridgeline Winds (mph)
Sunday Evening WSW 35-50
Sunday Night WSW 30-40
Monday Morning WSW 30-40
Monday Afternoon WSW 30-40

Issued: 2:21 PM PST Sunday, February 21, 2021

Extended Weather Synopsis

An offshore ridge starts building into the area Tuesday night as a trough exits to our east. The post-frontal snow showers should diminish and end by Wednesday morning with partially clearing skies. High and mid-level clouds increase throughout the day on Wednesday and may lower over the Olympics and Baker areas by the end of the day. Expect more sunshine than clouds on the east slopes of the Cascades and in the Mt. Hood area. A colder storm moves in on NW flow Wednesday night. A leading warm front should bring light to moderate snow into western Washington after midnight Wednesday night. Expect some warming for Mt. Hood and the southern parts of our forecast region. A cold front follows on Thursday with moderate to locally heavy snow. Sustained and significant post-frontal snowfall starts up late in the day and could continue through Friday night.

Extended Snow Level (ft)

Tuesday Night Wednesday Wednesday Night Thursday
West North 500' 1500' 1000' 1000'
Snoqualmie Pass 500' 2000' 1500' 1500'
Mt. Hood 1500' 2500' 2500' 2000'
West North Elevation
Tuesday Night 500'
Wednesday 1500'
Wednesday Night 1000'
Thursday 1000'
Snoqualmie Pass Elevation
Tuesday Night 500'
Wednesday 2000'
Wednesday Night 1500'
Thursday 1500'
Mt. Hood Elevation
Tuesday Night 1500'
Wednesday 2500'
Wednesday Night 2500'
Thursday 2000'

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

Previous forecast from Feb 21, 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’.