Issued: 2:37 PM PDT Sunday, April 9, 2023
by Dennis D'Amico

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

Weather Synopsis

An early April atmospheric river will continue to impact the region this afternoon and evening with widespread rain and snow. We'll see some of the highest precipitation rates and peak snow levels this afternoon and evening followed by the current wave of moisture tapering down overnight. Some of the strongest winds will also be over this same time period. Low-level easterly flow has been holding some of the stronger ridgeline winds at bay for the central/south WA Cascades near and east of the Cascade crest. As offshore flow wanes late this afternoon, some of those very strong SW winds blowing above ridgeline should begin to mix downward. 

Snow levels will start to fall Sunday night as a cool upper trough approaches from the west. The Olympics and northwest Cascades will be the first to cool later this evening, with a slower cooling trend for the remainder of the west slopes and Passes. The frontal boundary will more or less stay stagnant through mid-day Monday, with milder air along the east slopes of the Cascades and down near Mt Hood and cooler air to the west.  A second wave of moisture riding up along the same frontal boundary late Sunday night and Monday will generate more steady (stratiform) precipitation although with amounts that look significantly lower than Sunday. 

The entire frontal boundary will finally kick eastward Monday night, with significant cooling occurring after midnight and snow levels falling near 2500' near daybreak. That same upper level low will rotate an upper level disturbance through the region on Tuesday keeping mountain snow showers going all day long.  

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 Mostly cloudy with scattered light rain and snow showers.
Monday Mostly cloudy with scattered light rain and snow showers.
Sunday Night Moderate to heavy rain and snow early in the evening becoming light to occasionally moderate rain and snow overnight. Strong winds early tapering down quickly in the evening.
Monday Light to occasionally moderate rain and snow.
Sunday Night Moderate to occasionally heavy rain and snow in the evening becoming light to occasionally moderate rain and snow overnight. Strong winds early tapering down quickly in the evening.
Monday Light to occasionally moderate rain and snow.
Sunday Night Moderate to occasionally heavy rain and snow in the evening becoming light to occasionally moderate rain and snow overnight. Strong winds tapering down overnight.
Monday Light to occasionally moderate rain and snow. Moderate to strong ridgeline winds.
Sunday Night Light to moderate rain and snow in the evening becoming light overnight. Moderate to strong west winds at Pass level and ridgeline.
Monday Light to occasionally moderate rain and snow. Light to moderate Pass level and ridgeline west winds.
Sunday Night Moderate rain and snow in the evening becoming light to occasionally moderate overnight. Moderate to strong west winds at Pass level and ridgeline.
Monday Light to occasionally moderate rain and snow. Light to moderate Pass level and ridgeline west winds.
Sunday Night Light to moderate rain and snow in the evening becoming light overnight. Moderate winds.
Monday Light to occasionally moderate rain and snow.
Sunday Night Light to moderate rain and snow in the evening becoming light overnight. Moderate to strong ridgeline winds.
Monday Light to occasionally moderate rain and snow. Moderate ridgeline winds.
Sunday Night Light to occasionally moderate rain and snow. Moderate to strong ridgeline winds.
Monday Light to moderate rain and snow. Moderate to strong ridgeline winds, strongest in the afternoon.
Sunday Night Moderate rain and snow in the evening, then light to moderate rain and snow after midnight. Moderate to strong ridgeline winds.
Monday Light to moderate rain and snow. Moderate to strong ridgeline winds, strongest in the afternoon.

Issued: 2:37 PM PDT Sunday, April 9, 2023

Precipitation (in)

Sunday Night Monday Monday Night Tuesday
5 pm - 5 am 5 am - 5 pm 5 pm - 5 am 5 am - 5 pm
Hurricane Ridge LT 0.25 LT 0.10 LT 0.10 0.25
Mt Baker Ski Area 0.50 - 0.75 0.25 0.25 - 0.50 0.50
Mt. Loop - Barlow Pass 0.75 -1.00 0.25 - 0.50 0.25 0.25 - 0.50
Stevens Pass 0.25 - 0.50 0.25 LT 0.25 LT 0.25
Snoqualmie Pass 0.50 0.25 - 0.50 0.25 0.25
Crystal Mt 0.25 - 0.50 0.25 - 0.50 0.25 LT 0.25
Paradise 0.75 -1.00 0.50 - 0.75 0.25 - 0.50 0.25 - 0.50
White Pass 0.25 - 0.50 0.50 0.25 0.25
Washington Pass 0.25 - 0.50 LT 0.25 LT 0.10 LT 0.25
Mission Ridge LT 0.10 0.25 - 0.50 LT 0.10 LT 0.10
Salmon la Sac - Gallagher Head 0.25 0.25 - 0.50 0.25 LT 0.25
Tieton River - Darland Mt. 0.25 0.25 - 0.50 LT 0.25 LT 0.10
Mt Hood Meadows 0.75 0.25 - 0.50 0.25 - 0.50 0.25
Timberline 0.75 -1.00 0.50 0.25 - 0.50 0.25 - 0.50
Hurricane Ridge Precipitation (in)
Sunday Night LT 0.25
Monday LT 0.10
Monday Night LT 0.10
Tuesday 0.25
Mt Baker Ski Area Precipitation (in)
Sunday Night 0.50 - 0.75
Monday 0.25
Monday Night 0.25 - 0.50
Tuesday 0.50
Mt. Loop - Barlow Pass Precipitation (in)
Sunday Night 0.75 -1.00
Monday 0.25 - 0.50
Monday Night 0.25
Tuesday 0.25 - 0.50
Stevens Pass Precipitation (in)
Sunday Night 0.25 - 0.50
Monday 0.25
Monday Night LT 0.25
Tuesday LT 0.25
Snoqualmie Pass Precipitation (in)
Sunday Night 0.50
Monday 0.25 - 0.50
Monday Night 0.25
Tuesday 0.25
Crystal Mt Precipitation (in)
Sunday Night 0.25 - 0.50
Monday 0.25 - 0.50
Monday Night 0.25
Tuesday LT 0.25
Paradise Precipitation (in)
Sunday Night 0.75 -1.00
Monday 0.50 - 0.75
Monday Night 0.25 - 0.50
Tuesday 0.25 - 0.50
White Pass Precipitation (in)
Sunday Night 0.25 - 0.50
Monday 0.50
Monday Night 0.25
Tuesday 0.25
Washington Pass Precipitation (in)
Sunday Night 0.25 - 0.50
Monday LT 0.25
Monday Night LT 0.10
Tuesday LT 0.25
Mission Ridge Precipitation (in)
Sunday Night LT 0.10
Monday 0.25 - 0.50
Monday Night LT 0.10
Tuesday LT 0.10
Salmon la Sac - Gallagher Head Precipitation (in)
Sunday Night 0.25
Monday 0.25 - 0.50
Monday Night 0.25
Tuesday LT 0.25
Tieton River - Darland Mt. Precipitation (in)
Sunday Night 0.25
Monday 0.25 - 0.50
Monday Night LT 0.25
Tuesday LT 0.10
Mt Hood Meadows Precipitation (in)
Sunday Night 0.75
Monday 0.25 - 0.50
Monday Night 0.25 - 0.50
Tuesday 0.25
Timberline Precipitation (in)
Sunday Night 0.75 -1.00
Monday 0.50
Monday Night 0.25 - 0.50
Tuesday 0.25 - 0.50

Issued: 2:37 PM PDT Sunday, April 9, 2023

Snow Level (ft)

Sunday Evening Sunday Night Monday Morning Monday Afternoon Monday Evening Monday Night Tuesday Morning Tuesday Afternoon
Olympics 4500' 4000' 3500' 3500' 3500' 2500' 2500' 2500'
West North 5500' 4000' 3500' 3500' 3500' 3000' 2500' 2500'
West Central 6000' 4500' 4500' 4000' 4000' 3000' 2500' 2500'
West South 6500' 5500' 5000' 4500' 4000' 3000' 2500' 2500'
Stevens Pass 6500' 4500' 4500' 4500' 4000' 3000' 2500' 2500'
Snoqualmie Pass 6500' 4500' 4500' 4500' 4000' 3000' 2500' 2500'
East North 6000' 5000' 6000' 6000' 4500' 3500' 2500' 3500'
East Central 6500' 6000' 6000' 6000' 5000' 3500' 2500' 3000'
East South 7000' 7000' 7000' 6500' 5500' 3500' 2500' 3000'
Mt. Hood 8000' 8500' 9000' 9000' 5000' 3000' 2500' 2500'
Olympics Elevation
Sunday Evening 4500'
Sunday Night 4000'
Monday Morning 3500'
Monday Afternoon 3500'
Monday Evening 3500'
Monday Night 2500'
Tuesday Morning 2500'
Tuesday Afternoon 2500'
West North Elevation
Sunday Evening 5500'
Sunday Night 4000'
Monday Morning 3500'
Monday Afternoon 3500'
Monday Evening 3500'
Monday Night 3000'
Tuesday Morning 2500'
Tuesday Afternoon 2500'
West Central Elevation
Sunday Evening 6000'
Sunday Night 4500'
Monday Morning 4500'
Monday Afternoon 4000'
Monday Evening 4000'
Monday Night 3000'
Tuesday Morning 2500'
Tuesday Afternoon 2500'
West South Elevation
Sunday Evening 6500'
Sunday Night 5500'
Monday Morning 5000'
Monday Afternoon 4500'
Monday Evening 4000'
Monday Night 3000'
Tuesday Morning 2500'
Tuesday Afternoon 2500'
Stevens Pass Elevation
Sunday Evening 6500'
Sunday Night 4500'
Monday Morning 4500'
Monday Afternoon 4500'
Monday Evening 4000'
Monday Night 3000'
Tuesday Morning 2500'
Tuesday Afternoon 2500'
Snoqualmie Pass Elevation
Sunday Evening 6500'
Sunday Night 4500'
Monday Morning 4500'
Monday Afternoon 4500'
Monday Evening 4000'
Monday Night 3000'
Tuesday Morning 2500'
Tuesday Afternoon 2500'
East North Elevation
Sunday Evening 6000'
Sunday Night 5000'
Monday Morning 6000'
Monday Afternoon 6000'
Monday Evening 4500'
Monday Night 3500'
Tuesday Morning 2500'
Tuesday Afternoon 3500'
East Central Elevation
Sunday Evening 6500'
Sunday Night 6000'
Monday Morning 6000'
Monday Afternoon 6000'
Monday Evening 5000'
Monday Night 3500'
Tuesday Morning 2500'
Tuesday Afternoon 3000'
East South Elevation
Sunday Evening 7000'
Sunday Night 7000'
Monday Morning 7000'
Monday Afternoon 6500'
Monday Evening 5500'
Monday Night 3500'
Tuesday Morning 2500'
Tuesday Afternoon 3000'
Mt. Hood Elevation
Sunday Evening 8000'
Sunday Night 8500'
Monday Morning 9000'
Monday Afternoon 9000'
Monday Evening 5000'
Monday Night 3000'
Tuesday Morning 2500'
Tuesday Afternoon 2500'

Issued: 2:37 PM PDT Sunday, April 9, 2023

5000' Temperatures (°F)

Sunday Night Monday
Max / Min Max / Min
Olympics 31 / 26 32 / 26
West North 36 / 28 32 / 27
West Central 37 / 31 34 / 27
West South 37 / 32 36 / 32
Stevens Pass 38 / 30 37 / 30
Snoqualmie Pass 38 / 30 35 / 30
East North 38 / 30 37 / 29
East Central 38 / 31 38 / 31
East South 38 / 35 39 / 35
Mt. Hood 40 / 39 41 / 37
Olympics 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 26
Monday 32 / 26
West North 5000' Temperature Forecast
(Max / Min)
Sunday Night 36 / 28
Monday 32 / 27
West Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 37 / 31
Monday 34 / 27
West South 5000' Temperature Forecast
(Max / Min)
Sunday Night 37 / 32
Monday 36 / 32
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 38 / 30
Monday 37 / 30
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 38 / 30
Monday 35 / 30
East North 5000' Temperature Forecast
(Max / Min)
Sunday Night 38 / 30
Monday 37 / 29
East Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 38 / 31
Monday 38 / 31
East South 5000' Temperature Forecast
(Max / Min)
Sunday Night 38 / 35
Monday 39 / 35
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Sunday Night 40 / 39
Monday 41 / 37

Issued: 2:37 PM PDT Sunday, April 9, 2023

Ridgeline Winds (mph)

Sunday Evening Sunday Night Monday Morning Monday Afternoon
Olympics SW 15-25 SW 5-15 S 5-15 SW 5-15
West North SSW 15-25 SSW 5-15 S 10-20 S 5-15
West Central SW 25-35 SSW 15-25 S 5-15 SW 5-15
West South SW 20-30 SSW 10-20 SW 15-25 SW 15-25
Stevens Pass SW 15-25 SW 10-20 SW 5-15 SW 5-15
Snoqualmie Pass SW 20-30 SW 15-25 SW 10-20 SW 5-15
East North SW 20-30 SW 15-25 SW 10-20 SW 5-15
East Central SW 20-30 SW 15-25 SW 15-25 SW 15-25
East South SW 20-30 SW 10-20 SW 10-20 SW 20-30
Mt. Hood SW 25-35 SW 15-25 SW 20-30 SW 25-35
Olympics Ridgeline Winds (mph)
Sunday Evening SW 15-25
Sunday Night SW 5-15
Monday Morning S 5-15
Monday Afternoon SW 5-15
West North Ridgeline Winds (mph)
Sunday Evening SSW 15-25
Sunday Night SSW 5-15
Monday Morning S 10-20
Monday Afternoon S 5-15
West Central Ridgeline Winds (mph)
Sunday Evening SW 25-35
Sunday Night SSW 15-25
Monday Morning S 5-15
Monday Afternoon SW 5-15
West South Ridgeline Winds (mph)
Sunday Evening SW 20-30
Sunday Night SSW 10-20
Monday Morning SW 15-25
Monday Afternoon SW 15-25
Stevens Pass Ridgeline Winds (mph)
Sunday Evening SW 15-25
Sunday Night SW 10-20
Monday Morning SW 5-15
Monday Afternoon SW 5-15
Snoqualmie Pass Ridgeline Winds (mph)
Sunday Evening SW 20-30
Sunday Night SW 15-25
Monday Morning SW 10-20
Monday Afternoon SW 5-15
East North Ridgeline Winds (mph)
Sunday Evening SW 20-30
Sunday Night SW 15-25
Monday Morning SW 10-20
Monday Afternoon SW 5-15
East Central Ridgeline Winds (mph)
Sunday Evening SW 20-30
Sunday Night SW 15-25
Monday Morning SW 15-25
Monday Afternoon SW 15-25
East South Ridgeline Winds (mph)
Sunday Evening SW 20-30
Sunday Night SW 10-20
Monday Morning SW 10-20
Monday Afternoon SW 20-30
Mt. Hood Ridgeline Winds (mph)
Sunday Evening SW 25-35
Sunday Night SW 15-25
Monday Morning SW 20-30
Monday Afternoon SW 25-35

Issued: 2:37 PM PDT Sunday, April 9, 2023

Extended Weather Synopsis

Showers should wind down overnight Tuesday as snow levels fall to 1000-1500'.  The weakened upper low will drift across southern WA/OR on Wednesday and keep scattered showers in the forecast. As quickly as that feature moves out, a fresh upper level trough will move in on Thursday maintaining a chance of showers. 

Extended Snow Level (ft)

Tuesday Night Wednesday Wednesday Night Thursday
West North 1500' 3000' 1500' 4000'
Snoqualmie Pass 1500' 3000' 1500' 4000'
Mt. Hood 1500' 3000' 1500' 4000'
West North Elevation
Tuesday Night 1500'
Wednesday 3000'
Wednesday Night 1500'
Thursday 4000'
Snoqualmie Pass Elevation
Tuesday Night 1500'
Wednesday 3000'
Wednesday Night 1500'
Thursday 4000'
Mt. Hood Elevation
Tuesday Night 1500'
Wednesday 3000'
Wednesday Night 1500'
Thursday 4000'

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

Previous forecast from Apr 9, 2023

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’.