Issued: 2:07 PM PST Sunday, December 22, 2024
by Dennis D'Amico

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

Weather Synopsis

We're in a very active pattern over the next week with storm systems arriving roughly every 24 hours and increasingly strong and wet storms past Christmas and into the 2nd half of next week.  But before we get to the big ones, we'll have tonight's and Monday night's systems to contend with.  Warm frontal precipitation has spread over the area today and precipitation rates will intensify through Sunday afternoon and overnight.  Snow levels are highly location dependent, with warmer air worming its way into the Olympics, Mt Hood and west slopes of the Cascades and cooler air through the Cascade Passes and along the eastern slopes of the Cascades. Strong S-SE ridgeline winds will continue in many areas through this evening. Cool easterly flow will continue to drag snow levels down to Snoqualmie Pass level this afternoon through evening, but a rain/snow mix at 3000' will likely take hold sometime late evening even with easterly flow.

An upper trough passing through after midnight will turn the precipitation more showery early Monday morning and allow snow levels to settle into the 4000-4500' range (a bit cooler north of L. Chelan) and be accompanied blustery W-SW ridgeline winds. The heaviest post-frontal showers will likely be directed at the Mt Baker area late tonight. 

Upper level ridging will build over the inland NW on Monday and Monday morning showers will taper off. Freezing levels will bump up, especially for areas west of the Cascade crest and Mt Hood in the afternoon.  We should see some sunshine mid-day before high clouds from the next system approaches. 

SE winds from this next system will crank up rapidly Monday afternoon and the next round of precipitation will arrive Monday night. This frontal band will shear apart as it pushes inland, delivering moderate precipitation to most areas except higher precipitation totals for the south WA Cascades and Mt Hood.  Showers will follow on Tuesday with an upper level trough overhead.  

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 Stormy with moderate rain and snow becoming light to moderate showers around midnight. Strong ridgeline winds.
Monday Mostly cloudy in the morning with light isolated rain and snow showers, then partly sunny. Increasing high clouds in the afternoon. Ridgeline winds increasing and becoming moderate in the afternoon.
Sunday Night Stormy with moderate to occasionally heavy rain and snow becoming moderate showers after midnight. Strong ridgeline winds.
Monday Mostly cloudy in the morning with light scattered rain and snow showers, then partly sunny. Increasing high clouds in the afternoon. Ridgeline winds increasing and becoming moderate in the afternoon.
Sunday Night Stormy with moderate to occasionally heavy rain and snow becoming light to moderate showers after midnight. Strong ridgeline winds.
Monday Mostly cloudy in the morning with light isolated rain and snow showers, then partly sunny. Increasing high clouds in the afternoon. Ridgeline winds increasing and becoming moderate in the afternoon.
Sunday Night Stormy with moderate to occasionally heavy rain and snow becoming light to moderate showers after midnight. Strong ridgeline winds.
Monday Mostly cloudy in the morning with light isolated rain and snow showers, then partly sunny. Increasing high clouds in the early afternoon. Ridgeline winds increasing and becoming moderate in the afternoon.
Sunday Night Stormy with moderate rain and snow becoming light to moderate showers after midnight. Moderate E Pass level winds/SE winds at ridgeline becoming moderate to Strong W winds after midnight.
Monday Mostly cloudy in the morning with light isolated rain and snow showers, then partly sunny. Increasing high clouds in the early afternoon. Ridgeline winds increasing and becoming moderate in the afternoon. Light to moderate W Pass and ridgeline winds becoming moderate E-SE in the afternoon.
Sunday Night Stormy with moderate to occasionally heavy rain and snow becoming light to moderate showers after midnight. Moderate E Pass level winds/SE winds at ridgeline becoming moderate to Strong W winds after midnight.
Monday Mostly cloudy in the morning with light isolated rain and snow showers, then partly sunny. Increasing high clouds in the early afternoon. Light to moderate W Pass and ridgeline winds becoming moderate E-SE in the afternoon.
Sunday Night Stormy with moderate rain and snow becoming light to occasionally moderate showers after midnight. Strong ridgeline winds.
Monday Mostly cloudy in the morning with light isolated rain and snow showers, then partly sunny. Increasing high clouds in the early afternoon. Ridgeline winds increasing and becoming moderate in the afternoon.
Sunday Night Stormy with moderate rain and snow becoming light to occasionally moderate showers after midnight. Strong ridgeline winds.
Monday Mostly cloudy in the morning with light isolated rain and snow showers, then partly sunny. Increasing high clouds in the early afternoon. Ridgeline winds increasing and becoming moderate in the afternoon.
Sunday Night Stormy with moderate rain and snow becoming light to occasionally moderate showers after midnight. Strong ridgeline winds.
Monday Mostly cloudy in the morning with light isolated rain and snow showers, then partly to mostly cloudy with increasing high clouds late morning. Ridgeline winds increasing and becoming moderate in the afternoon.
Sunday Night Stormy with moderate to occasionally heavy rain and snow becoming light to moderate showers after midnight. Strong ridgeline winds.
Monday Mostly cloudy in the morning with light isolated rain and snow showers, then partly to mostly cloudy with increasing high clouds late morning. Ridgeline winds becoming strong in the afternoon.

Issued: 2:07 PM PST Sunday, December 22, 2024

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 0.25 - 0.50 LT 0.10 0.25 0.25
Mt Baker Ski Area 1.00 - 1.50 LT 0.10 0.50 0.50
Mt. Loop - Barlow Pass 1.00 LT 0.10 0.50 0.50
Stevens Pass 0.50 - 0.75 LT 0.10 0.25 0.25 - 0.50
Snoqualmie Pass 0.75 -1.00 LT 0.10 0.25 - 0.50 0.25 - 0.50
Crystal Mt 0.50 - 0.75 LT 0.10 0.50 - 0.75 0.25
Paradise 0.75 -1.00 LT 0.10 0.50 - 0.75 0.25 - 0.50
White Pass 0.50 LT 0.10 0.25 - 0.50 0.25
Washington Pass 0.50 LT 0.10 0.25 0.25
Mission Ridge 0.25 0 0.25 LT 0.25
Salmon la Sac - Gallagher Head 0.50 LT 0.10 0.25 - 0.50 0.25
Tieton River - Darland Mt. 0.50 LT 0.10 0.50 0.25
Mt Hood Meadows 1.00 - 1.50 LT 0.10 1.00 - 1.50 0.25 - 0.50
Timberline 1.00 - 1.50 LT 0.10 1.00 - 1.50 0.25 - 0.50
Hurricane Ridge Precipitation (in)
Sunday Night 0.25 - 0.50
Monday LT 0.10
Monday Night 0.25
Tuesday 0.25
Mt Baker Ski Area Precipitation (in)
Sunday Night 1.00 - 1.50
Monday LT 0.10
Monday Night 0.50
Tuesday 0.50
Mt. Loop - Barlow Pass Precipitation (in)
Sunday Night 1.00
Monday LT 0.10
Monday Night 0.50
Tuesday 0.50
Stevens Pass Precipitation (in)
Sunday Night 0.50 - 0.75
Monday LT 0.10
Monday Night 0.25
Tuesday 0.25 - 0.50
Snoqualmie Pass Precipitation (in)
Sunday Night 0.75 -1.00
Monday LT 0.10
Monday Night 0.25 - 0.50
Tuesday 0.25 - 0.50
Crystal Mt Precipitation (in)
Sunday Night 0.50 - 0.75
Monday LT 0.10
Monday Night 0.50 - 0.75
Tuesday 0.25
Paradise Precipitation (in)
Sunday Night 0.75 -1.00
Monday LT 0.10
Monday Night 0.50 - 0.75
Tuesday 0.25 - 0.50
White Pass Precipitation (in)
Sunday Night 0.50
Monday LT 0.10
Monday Night 0.25 - 0.50
Tuesday 0.25
Washington Pass Precipitation (in)
Sunday Night 0.50
Monday LT 0.10
Monday Night 0.25
Tuesday 0.25
Mission Ridge Precipitation (in)
Sunday Night 0.25
Monday 0
Monday Night 0.25
Tuesday LT 0.25
Salmon la Sac - Gallagher Head Precipitation (in)
Sunday Night 0.50
Monday LT 0.10
Monday Night 0.25 - 0.50
Tuesday 0.25
Tieton River - Darland Mt. Precipitation (in)
Sunday Night 0.50
Monday LT 0.10
Monday Night 0.50
Tuesday 0.25
Mt Hood Meadows Precipitation (in)
Sunday Night 1.00 - 1.50
Monday LT 0.10
Monday Night 1.00 - 1.50
Tuesday 0.25 - 0.50
Timberline Precipitation (in)
Sunday Night 1.00 - 1.50
Monday LT 0.10
Monday Night 1.00 - 1.50
Tuesday 0.25 - 0.50

Issued: 2:07 PM PST Sunday, December 22, 2024

Snow Level (ft)

Sunday Evening* Sunday Night Monday Morning Monday Afternoon* Monday Evening* Monday Night* Tuesday Morning Tuesday Afternoon
Olympics 6000' 4500' 4000' 7000' 7000' 4500' 3500' 3500'
West North 5000' 4000' 4000' 4500' 7000' 3500' 3500' 3500'
West Central 5000' 4500' 4000' 5000' 7000' 3500' 3500' 3500'
West South 5000' 4500' 4000' 6500' 7000' 3500' 3500' 3500'
Stevens Pass 3000' 4000' 4000' 4500' 4000' 3000' 3500' 3500'
Snoqualmie Pass 3500' 4500' 4000' 6000' 6000' 3500' 3500' 3500'
East North 2500' 3500' 3500' 4500' 3500' 3000' 3500' 4000'
East Central 3000' 4000' 4000' 4500' 3500' 3000' 3500' 4000'
East South 4000' 5000' 4000' 6500' 4000' 3500' 3500' 3500'
Mt. Hood 6500' 5000' 5000' 8000' 7500' 6000' 5000' 3500'
Olympics Elevation
Sunday Evening* 6000'
Sunday Night 4500'
Monday Morning 4000'
Monday Afternoon* 7000'
Monday Evening* 7000'
Monday Night* 4500'
Tuesday Morning 3500'
Tuesday Afternoon 3500'
West North Elevation
Sunday Evening* 5000'
Sunday Night 4000'
Monday Morning 4000'
Monday Afternoon* 4500'
Monday Evening* 7000'
Monday Night* 3500'
Tuesday Morning 3500'
Tuesday Afternoon 3500'
West Central Elevation
Sunday Evening* 5000'
Sunday Night 4500'
Monday Morning 4000'
Monday Afternoon* 5000'
Monday Evening* 7000'
Monday Night* 3500'
Tuesday Morning 3500'
Tuesday Afternoon 3500'
West South Elevation
Sunday Evening* 5000'
Sunday Night 4500'
Monday Morning 4000'
Monday Afternoon* 6500'
Monday Evening* 7000'
Monday Night* 3500'
Tuesday Morning 3500'
Tuesday Afternoon 3500'
Stevens Pass Elevation
Sunday Evening* 3000'
Sunday Night 4000'
Monday Morning 4000'
Monday Afternoon* 4500'
Monday Evening* 4000'
Monday Night* 3000'
Tuesday Morning 3500'
Tuesday Afternoon 3500'
Snoqualmie Pass Elevation
Sunday Evening* 3500'
Sunday Night 4500'
Monday Morning 4000'
Monday Afternoon* 6000'
Monday Evening* 6000'
Monday Night* 3500'
Tuesday Morning 3500'
Tuesday Afternoon 3500'
East North Elevation
Sunday Evening* 2500'
Sunday Night 3500'
Monday Morning 3500'
Monday Afternoon* 4500'
Monday Evening* 3500'
Monday Night* 3000'
Tuesday Morning 3500'
Tuesday Afternoon 4000'
East Central Elevation
Sunday Evening* 3000'
Sunday Night 4000'
Monday Morning 4000'
Monday Afternoon* 4500'
Monday Evening* 3500'
Monday Night* 3000'
Tuesday Morning 3500'
Tuesday Afternoon 4000'
East South Elevation
Sunday Evening* 4000'
Sunday Night 5000'
Monday Morning 4000'
Monday Afternoon* 6500'
Monday Evening* 4000'
Monday Night* 3500'
Tuesday Morning 3500'
Tuesday Afternoon 3500'
Mt. Hood Elevation
Sunday Evening* 6500'
Sunday Night 5000'
Monday Morning 5000'
Monday Afternoon* 8000'
Monday Evening* 7500'
Monday Night* 6000'
Tuesday Morning 5000'
Tuesday Afternoon 3500'

Issued: 2:07 PM PST Sunday, December 22, 2024

5000' Temperatures (°F)

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

Issued: 2:07 PM PST Sunday, December 22, 2024

Ridgeline Winds (mph)

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

Issued: 2:07 PM PST Sunday, December 22, 2024

Extended Weather Synopsis

We're in for a wet Christmas period through the weekend with a series of wet, powerful storms and a likely atmospheric river or two.  There will be heavy snow in the mountains, but snow levels are also likely to fluctuate so stay tuned for details as we get closer.  

Extended Snow Level (ft)

Tuesday Night Wednesday * Wednesday Night* Thursday *
West North 2000' 2500' 2500' 3000'
Snoqualmie Pass 2500' 3000' 2500' 3000'
Mt. Hood 2500' 3000' 4000' 4000'
West North Elevation
Tuesday Night 2000'
Wednesday * 2500'
Wednesday Night* 2500'
Thursday * 3000'
Snoqualmie Pass Elevation
Tuesday Night 2500'
Wednesday * 3000'
Wednesday Night* 2500'
Thursday * 3000'
Mt. Hood Elevation
Tuesday Night 2500'
Wednesday * 3000'
Wednesday Night* 4000'
Thursday * 4000'

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

Previous forecast from Dec 22, 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’.