Issued: 2:41 PM PDT Sunday, April 23, 2023
by Robert Hahn

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

Weather Synopsis

A frontal system brought significantly milder (and largely above-freezing) temperatures into the Pacific Northwest by early Sunday. A cold frontal passage late Sunday morning initiated a cooling trend, but only a few of the higher NWAC stations have dipped below freezing. A closed, compact, and well-organized trailing low will track toward the Olympics and cross the central Washington Cascades early Monday. Rain and snow associated with this feature has started for the Olympics on Sunday afternoon. This light to occasionally moderate precipitation should increase across the Cascades overnight. Weak convergence enhancement could develop over western Watcom County around midnight, quickly dropping south to the central Washington Cascades in the early through mid-morning hours on Monday. The cooling trend should continue Sunday night with snow levels dropping from 4000-4500 ft in the evening to around 3000 ft by Monday morning.

Light snow showers gradually decrease across the west slopes of the Cascades on Monday with snow levels gradually rising back up to 3500 ft by the afternoon. Expect minimal spillover onto the east slopes of the Cascades early in the day where partly cloudy skies should develop by the afternoon. Mostly light ridgeline winds decrease behind the departed low, but remain in the moderate range for Mt Hood.

An offshore ridge expands into our region Monday night through Tuesday, bringing increasingly mild conditions. Freezing levels could rise to 9000 ft by Tuesday for Mt Hood although they will only rise to around 6000-6500 ft for the mountains of Washington State. Partly to mostly cloudy skies should linger along the west slopes of the Cascades with clearing skies on the lee slopes.

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 Light rain and snow tapering to showers after midnight.
Monday Mostly cloudy with isolated rain/snow showers in the morning, then becoming partly cloudy in the afternoon.
Sunday Night Light to occasionally moderate rain and snow. Some convergence enhancement possible. Decreasing moderate ridgeline winds.
Monday Light rain and snow showers.
Sunday Night Light to occasionally moderate rain and snow. Some convergence enhancement in the early morning hours.
Monday Decreasing light rain and snow showers with weak convergence enhancement possible in the southern part.
Sunday Night Light rain to moderate rain and snow, heaviest at Paradise while Crystal is largely rain shadowed.
Monday Decreasing light rain and snow showers.
Sunday Night Increasing light rain and snow. Light ridgeline and W wind at the Pass.
Monday Decreasing light snow showers with weak convergence possible. Light ridgeline and W wind at the Pass.
Sunday Night Increasing light rain and snow. Increasing ridgeline winds becoming light to moderate. Increasing light W wind at the Pass.
Monday Decreasing light snow showers with weak convergence possible. Decreasing light to moderate ridgeline winds becoming light. Light W wind at the Pass.
Sunday Night Periods of very light rain or snow.
Monday Isolated light rain or snow showers early, then becoming mostly to partly cloudy.
Sunday Night Light rain or snow at times.
Monday Decreasing light rain or snow showers with more frequent sun breaks in the afternoon.
Sunday Night Increasing periods of light rain or snow.
Monday Light rain or snow showers near the Cascade Crest ending in the morning, then becoming partly cloudy in the afternoon.
Sunday Night Increasing light to occasionally moderate rain or snow. Moderate to strong ridgeline winds.
Monday Decreasing mostly light rain or snow showers. Decreasing moderate ridgeline winds.

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

Snow Level (ft)

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

5000' Temperatures (°F)

Sunday Night Monday
Max / Min Max / Min
Olympics 30 / 27 31 / 26
West North 30 / 27 32 / 26
West Central 31 / 27 32 / 26
West South 32 / 27 31 / 26
Stevens Pass 32 / 27 32 / 26
Snoqualmie Pass 31 / 27 31 / 26
East North 32 / 26 33 / 25
East Central 34 / 30 34 / 29
East South 36 / 29 34 / 29
Mt. Hood 34 / 29 33 / 28
Olympics 5000' Temperature Forecast
(Max / Min)
Sunday Night 30 / 27
Monday 31 / 26
West North 5000' Temperature Forecast
(Max / Min)
Sunday Night 30 / 27
Monday 32 / 26
West Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 27
Monday 32 / 26
West South 5000' Temperature Forecast
(Max / Min)
Sunday Night 32 / 27
Monday 31 / 26
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 32 / 27
Monday 32 / 26
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 27
Monday 31 / 26
East North 5000' Temperature Forecast
(Max / Min)
Sunday Night 32 / 26
Monday 33 / 25
East Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 34 / 30
Monday 34 / 29
East South 5000' Temperature Forecast
(Max / Min)
Sunday Night 36 / 29
Monday 34 / 29
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Sunday Night 34 / 29
Monday 33 / 28

Ridgeline Winds (mph)

Sunday Evening Sunday Night Monday Morning Monday Afternoon
Olympics SSW 10-20 WSW 5-15 WSW 0-10 WSW 0-10
West North S 20-30 SSW 10-20 W 0-10 WSW 0-10
West Central SSW 10-20 SW 10-20 W 0-10 W 0-10
West South WSW 10-20 WSW 15-25 W 10-20 WNW 5-15
Stevens Pass WSW 0-10 SW 5-15 W 5-15 WNW 5-15
Snoqualmie Pass WSW 5-15 WSW 10-20 W 15-25 WNW 5-15
East North SW 5-15 WSW 5-15 W 0-10 WNW 0-10
East Central WSW 10-20 WSW 10-20 W 15-25 WNW 5-15
East South WSW 5-15 WSW 10-20 W 15-25 WNW 5-15
Mt. Hood WSW 20-30 WSW 25-35 W 20-30 W 15-25
Olympics Ridgeline Winds (mph)
Sunday Evening SSW 10-20
Sunday Night WSW 5-15
Monday Morning WSW 0-10
Monday Afternoon WSW 0-10
West North Ridgeline Winds (mph)
Sunday Evening S 20-30
Sunday Night SSW 10-20
Monday Morning W 0-10
Monday Afternoon WSW 0-10
West Central Ridgeline Winds (mph)
Sunday Evening SSW 10-20
Sunday Night SW 10-20
Monday Morning W 0-10
Monday Afternoon W 0-10
West South Ridgeline Winds (mph)
Sunday Evening WSW 10-20
Sunday Night WSW 15-25
Monday Morning W 10-20
Monday Afternoon WNW 5-15
Stevens Pass Ridgeline Winds (mph)
Sunday Evening WSW 0-10
Sunday Night SW 5-15
Monday Morning W 5-15
Monday Afternoon WNW 5-15
Snoqualmie Pass Ridgeline Winds (mph)
Sunday Evening WSW 5-15
Sunday Night WSW 10-20
Monday Morning W 15-25
Monday Afternoon WNW 5-15
East North Ridgeline Winds (mph)
Sunday Evening SW 5-15
Sunday Night WSW 5-15
Monday Morning W 0-10
Monday Afternoon WNW 0-10
East Central Ridgeline Winds (mph)
Sunday Evening WSW 10-20
Sunday Night WSW 10-20
Monday Morning W 15-25
Monday Afternoon WNW 5-15
East South Ridgeline Winds (mph)
Sunday Evening WSW 5-15
Sunday Night WSW 10-20
Monday Morning W 15-25
Monday Afternoon WNW 5-15
Mt. Hood Ridgeline Winds (mph)
Sunday Evening WSW 20-30
Sunday Night WSW 25-35
Monday Morning W 20-30
Monday Afternoon W 15-25

Extended Weather Synopsis

An increasingly strong upper-level ridge just offshore continues to amplify. Expect warming temperatures and clearing skies with snow levels rising above 10,000 ft across the region by Thursday. A system rounds the top of the ridge over British Columbia on Wednesday and could temporarily limit warming or bring some cloud cover to areas near the Canadian border.

Extended Snow Level (ft)

Tuesday Night Wednesday Wednesday Night Thursday
West North 5500' 8000' 8000' 10000'
Snoqualmie Pass 7000' 9000' 9500' 12000'
Mt. Hood 10000' 11000' 11500' 12500'
West North Elevation
Tuesday Night 5500'
Wednesday 8000'
Wednesday Night 8000'
Thursday 10000'
Snoqualmie Pass Elevation
Tuesday Night 7000'
Wednesday 9000'
Wednesday Night 9500'
Thursday 12000'
Mt. Hood Elevation
Tuesday Night 10000'
Wednesday 11000'
Wednesday Night 11500'
Thursday 12500'

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

Previous forecast from Apr 22, 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’.