Issued: 7:03 AM PST Sunday, December 29, 2024
by Dallas Glass

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

Weather Synopsis

While everyone should see some precipitation by the end of the day, this system will focus most of its energy from I-90 to the south. Expect stormy conditions on Mt Hood, Mt Saint Helens, and Mt Rainier with periods of heavy snow and gusty winds developing. Even areas near and east of the crest like Ahtanum Meadows and the Wenathchee Mountains could see a period of heavier snowfall in the morning.

On Sunday, look for precipitation to spread from south to north along both sides of the range. Snow levels hover around 3000 ft for most locations keeping the Passes as snow. The question mark, of course, is Snoqualmie Pass where you may find mixed precipitation with a changeover to rain in the afternoon. Along with the band of heavier rain/snow, gusty SE winds have developed along the Cascade crest, these should die down before swinging to the W and ramping back up in the afternoon. Moderate to strong and gusty winds will continue to build into the evening. 

An approaching trough shoves the front eastward this evening. With plenty of low-level moisture, onshore (west) flow, and a relatively unstable atmosphere, this should produce significant snow showers along the west slopes of the Cascades, with markedly less precipitation venturing further east. The heaviest precipitation occurs under a well defined Puget Sound Convergence Zone. The narrow band of rain and snow will focus on the southern Mountain Loop and Hwy 2 areas but could swing towards I-90. 

As the open trough shifts overhead on Monday, showers should continue in the Olympics, western forecast zones, and passes. Gradual cooling should help add a few more inches of light fluffy snow to the weekend's snow totals. Eventually, a transient high pressure ridge should bring shower activity to an end Monday night into Tuesday.

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 Snow in the morning becoming showers with possible sun breaks in the afternoon. Winds becoming W light to moderate.
Sunday Night Showers mainly in the southern and western Olympics. Moderate and gusty W winds decreasing slightly.
Sunday Cloudy in the morning with a few isolated showers. Snow developing in the afternoon.
Sunday Night Snow mainly in the evening, becoming showers. Light to moderate WSW winds decreasing.
Sunday Cloudy in the morning with snow increasing through the day.
Sunday Night Snow in the evening, becoming showers. A Puget Sound Convergence Zone will bring locally heavy precipitation to the Mountain Loop Hwy and Hwy 2 corridors. Moderate W winds decreasing.
Sunday Stormy with moderate to occasionally heavy snow in the morning, decreasing slightly in the afternoon. Moderate and gusty SE ridgeline winds strongest near the crest, turning W and decreasing.
Sunday Night Snow in the evening then becoming showers. Moderate and gusty W winds decreasing.
Sunday Snow could be moderate at times. Light E flow at pass level turning W in the morning. Ridgeline winds turning W.
Sunday Night Snow in the evening could be heavy at times with a Puget Sound Convergence Zone. Becoming snow showers. W flow at pass level. Light to moderate W winds decreasing.
Sunday Rain and snow could be moderate at times. Light E flow at pass level turning W in the morning. Mixed precipitation road level, likely becoming rain in the afternoon. Ridgeline winds turning W and becoming light to moderate.
Sunday Night Stormy in the evening. Snow could be moderate to heavy with a Puget Sound Convergence Zone. W flow at pass level. Moderate W winds decreasing slightly.
Sunday Cloudy in the morning with light snow showers in the afternoon. Winds becoming W and increasing slightly.
Sunday Night Cloudy with snow mainly in the evening. Light to moderate W winds.
Sunday Cloudy with periods of rain and snow. Light to moderate E winds turning W and increasing during the morning.
Sunday Night Cloudy with snow showers. Moderate to strong and gusty WNW winds decreasing slightly.
Sunday Cloudy with rain and snow, heaviest in the morning, becoming more showery in the afternoon. Moderate SE winds turning W.
Sunday Night Cloudy with light snow showers. Strong and gusty W winds decreasing.
Sunday Stormy. Periods of heavy precipitation and strong and gusty winds. Winds increasing in the afternoon.
Sunday Night Stormy. Periods of heavy precipitation with strong and gusty winds peaking in the evening then decreasing slightly overnight.

Issued: 7:03 AM PST Sunday, December 29, 2024

Precipitation (in)

Sunday Sunday Night Monday
4 am - 4 pm 4 pm - 4 am 4 am - 4 pm
Hurricane Ridge 0.25 LT 0.25 LT 0.10
Mt Baker Ski Area LT 0.25 0.25 LT 0.25
Mt. Loop - Barlow Pass 0.25 0.50 - 0.75 0.25
Stevens Pass 0.25 0.50 - 0.75 LT 0.25
Snoqualmie Pass 0.50 0.50 - 0.75 0.25
Crystal Mt 0.50 0.25 LT 0.10
Paradise 0.75 -1.00 0.50 - 0.75 0.25
White Pass 0.50 - 0.75 0.50 LT 0.25
Washington Pass LT 0.25 LT 0.25 LT 0.10
Mission Ridge 0.25 LT 0.25 0
Salmon la Sac - Gallagher Head 0.25 - 0.50 0.25 LT 0.25
Tieton River - Darland Mt. 0.25 - 0.50 LT 0.25 LT 0.10
Mt Hood Meadows 1.00 0.75 -1.00 0.25
Timberline 1.00 0.75 -1.00 0.25
Hurricane Ridge Precipitation (in)
Sunday 0.25
Sunday Night LT 0.25
Monday LT 0.10
Mt Baker Ski Area Precipitation (in)
Sunday LT 0.25
Sunday Night 0.25
Monday LT 0.25
Mt. Loop - Barlow Pass Precipitation (in)
Sunday 0.25
Sunday Night 0.50 - 0.75
Monday 0.25
Stevens Pass Precipitation (in)
Sunday 0.25
Sunday Night 0.50 - 0.75
Monday LT 0.25
Snoqualmie Pass Precipitation (in)
Sunday 0.50
Sunday Night 0.50 - 0.75
Monday 0.25
Crystal Mt Precipitation (in)
Sunday 0.50
Sunday Night 0.25
Monday LT 0.10
Paradise Precipitation (in)
Sunday 0.75 -1.00
Sunday Night 0.50 - 0.75
Monday 0.25
White Pass Precipitation (in)
Sunday 0.50 - 0.75
Sunday Night 0.50
Monday LT 0.25
Washington Pass Precipitation (in)
Sunday LT 0.25
Sunday Night LT 0.25
Monday LT 0.10
Mission Ridge Precipitation (in)
Sunday 0.25
Sunday Night LT 0.25
Monday 0
Salmon la Sac - Gallagher Head Precipitation (in)
Sunday 0.25 - 0.50
Sunday Night 0.25
Monday LT 0.25
Tieton River - Darland Mt. Precipitation (in)
Sunday 0.25 - 0.50
Sunday Night LT 0.25
Monday LT 0.10
Mt Hood Meadows Precipitation (in)
Sunday 1.00
Sunday Night 0.75 -1.00
Monday 0.25
Timberline Precipitation (in)
Sunday 1.00
Sunday Night 0.75 -1.00
Monday 0.25

Issued: 7:03 AM PST Sunday, December 29, 2024

Snow Level (ft)

Sunday Morning* Sunday Afternoon Sunday Evening Sunday Night Monday Morning Monday Afternoon
Olympics 3000' 3000' 2500' 2000' 2000' 2500'
West North 2500' 3000' 2500' 2000' 2000' 2500'
West Central 3000' 3000' 2500' 2000' 2000' 2500'
West South 3000' 3500' 2500' 2000' 2000' 2500'
Stevens Pass 3000' 3500' 2500' 2000' 2000' 2000'
Snoqualmie Pass 3000' 3500' 2500' 2000' 2000' 2500'
East North 2000' 3000' 2500' 2000' 1500' 2000'
East Central 2500' 3000' 2500' 2000' 2000' 2000'
East South 3000' 3500' 2500' 2000' 2000' 2500'
Mt. Hood 3000' 3500' 2500' 2500' 2500' 3000'
Olympics Elevation
Sunday Morning* 3000'
Sunday Afternoon 3000'
Sunday Evening 2500'
Sunday Night 2000'
Monday Morning 2000'
Monday Afternoon 2500'
West North Elevation
Sunday Morning* 2500'
Sunday Afternoon 3000'
Sunday Evening 2500'
Sunday Night 2000'
Monday Morning 2000'
Monday Afternoon 2500'
West Central Elevation
Sunday Morning* 3000'
Sunday Afternoon 3000'
Sunday Evening 2500'
Sunday Night 2000'
Monday Morning 2000'
Monday Afternoon 2500'
West South Elevation
Sunday Morning* 3000'
Sunday Afternoon 3500'
Sunday Evening 2500'
Sunday Night 2000'
Monday Morning 2000'
Monday Afternoon 2500'
Stevens Pass Elevation
Sunday Morning* 3000'
Sunday Afternoon 3500'
Sunday Evening 2500'
Sunday Night 2000'
Monday Morning 2000'
Monday Afternoon 2000'
Snoqualmie Pass Elevation
Sunday Morning* 3000'
Sunday Afternoon 3500'
Sunday Evening 2500'
Sunday Night 2000'
Monday Morning 2000'
Monday Afternoon 2500'
East North Elevation
Sunday Morning* 2000'
Sunday Afternoon 3000'
Sunday Evening 2500'
Sunday Night 2000'
Monday Morning 1500'
Monday Afternoon 2000'
East Central Elevation
Sunday Morning* 2500'
Sunday Afternoon 3000'
Sunday Evening 2500'
Sunday Night 2000'
Monday Morning 2000'
Monday Afternoon 2000'
East South Elevation
Sunday Morning* 3000'
Sunday Afternoon 3500'
Sunday Evening 2500'
Sunday Night 2000'
Monday Morning 2000'
Monday Afternoon 2500'
Mt. Hood Elevation
Sunday Morning* 3000'
Sunday Afternoon 3500'
Sunday Evening 2500'
Sunday Night 2500'
Monday Morning 2500'
Monday Afternoon 3000'

Issued: 7:03 AM PST Sunday, December 29, 2024

5000' Temperatures (°F)

Sunday Sunday Night
Max / Min Max / Min
Olympics 30 / 27 29 / 26
West North 30 / 27 29 / 25
West Central 30 / 27 29 / 26
West South 29 / 26 28 / 23
Stevens Pass 30 / 28 30 / 26
Snoqualmie Pass 29 / 27 29 / 26
East North 25 / 21 24 / 20
East Central 30 / 26 30 / 23
East South 30 / 27 28 / 26
Mt. Hood 30 / 28 28 / 26
Olympics 5000' Temperature Forecast
(Max / Min)
Sunday 30 / 27
Sunday Night 29 / 26
West North 5000' Temperature Forecast
(Max / Min)
Sunday 30 / 27
Sunday Night 29 / 25
West Central 5000' Temperature Forecast
(Max / Min)
Sunday 30 / 27
Sunday Night 29 / 26
West South 5000' Temperature Forecast
(Max / Min)
Sunday 29 / 26
Sunday Night 28 / 23
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Sunday 30 / 28
Sunday Night 30 / 26
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Sunday 29 / 27
Sunday Night 29 / 26
East North 5000' Temperature Forecast
(Max / Min)
Sunday 25 / 21
Sunday Night 24 / 20
East Central 5000' Temperature Forecast
(Max / Min)
Sunday 30 / 26
Sunday Night 30 / 23
East South 5000' Temperature Forecast
(Max / Min)
Sunday 30 / 27
Sunday Night 28 / 26
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Sunday 30 / 28
Sunday Night 28 / 26

Issued: 7:03 AM PST Sunday, December 29, 2024

Ridgeline Winds (mph)

Sunday Morning Sunday Afternoon Sunday Evening Sunday Night
Olympics VAR 0-10 W 10-20 W 15-25 W 10-20
West North VAR 0-10 SW 5-15 WSW 10-20 WSW 5-15
West Central VAR 0-10 WSW 5-15 W 15-25 W 5-15
West South SE 15-25 W 10-20 W 15-25 W 10-20
Stevens Pass SE 5-15 W 5-15 W 10-20 W 5-15
Snoqualmie Pass SE 5-15 W 10-20 W 15-25 W 10-20
East North VAR 0-10 W 5-15 W 10-20 W 10-20
East Central E 10-20 W 15-25 WNW 20-30 WNW 15-25
East South SE 15-25 W 15-25 W 25-35 W 15-25
Mt. Hood W 20-30 W 25-35 W 30-40 W 20-30
Olympics Ridgeline Winds (mph)
Sunday Morning VAR 0-10
Sunday Afternoon W 10-20
Sunday Evening W 15-25
Sunday Night W 10-20
West North Ridgeline Winds (mph)
Sunday Morning VAR 0-10
Sunday Afternoon SW 5-15
Sunday Evening WSW 10-20
Sunday Night WSW 5-15
West Central Ridgeline Winds (mph)
Sunday Morning VAR 0-10
Sunday Afternoon WSW 5-15
Sunday Evening W 15-25
Sunday Night W 5-15
West South Ridgeline Winds (mph)
Sunday Morning SE 15-25
Sunday Afternoon W 10-20
Sunday Evening W 15-25
Sunday Night W 10-20
Stevens Pass Ridgeline Winds (mph)
Sunday Morning SE 5-15
Sunday Afternoon W 5-15
Sunday Evening W 10-20
Sunday Night W 5-15
Snoqualmie Pass Ridgeline Winds (mph)
Sunday Morning SE 5-15
Sunday Afternoon W 10-20
Sunday Evening W 15-25
Sunday Night W 10-20
East North Ridgeline Winds (mph)
Sunday Morning VAR 0-10
Sunday Afternoon W 5-15
Sunday Evening W 10-20
Sunday Night W 10-20
East Central Ridgeline Winds (mph)
Sunday Morning E 10-20
Sunday Afternoon W 15-25
Sunday Evening WNW 20-30
Sunday Night WNW 15-25
East South Ridgeline Winds (mph)
Sunday Morning SE 15-25
Sunday Afternoon W 15-25
Sunday Evening W 25-35
Sunday Night W 15-25
Mt. Hood Ridgeline Winds (mph)
Sunday Morning W 20-30
Sunday Afternoon W 25-35
Sunday Evening W 30-40
Sunday Night W 20-30

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

Previous forecast from Dec 28, 2024

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’.