Issued: 2:45 PM PST Sunday, December 10, 2023
by Robert Hahn

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

Weather Synopsis

2:45 PM update: fixed extended snow levels.

On Sunday afternoon, an atmospheric river event draws toward a close as a front pushes south of Mt Hood. Light post-frontal rain and snow shower activity gradually eased across the region in its wake on Sunday, but there's not much instability or energy to the showers. The cold front also brought in very modest cooling to the west slopes of the Cascades, but the east slopes can expect little change in temperature. A weak upper-level disturbance and associated shortwave trough arriving from the NW will maintain the very light shower and some weak convergence over Skagit or Snohomish counties on Sunday evening. The shower activity should taper overnight.

By Monday, we enter a milder and drier-than-average weather pattern. A developing ridge of high pressure just offshore brings gradual clearing on Monday. Skies start mostly cloudy, but most areas should be partly cloudy to mostly clear by the afternoon.

With the help of light and variable winds aloft, a cold pool begins to re-develop east of the Cascades on Monday with light E flow through the mountain gaps. By Tuesday, these winds should be in the moderate range with an increasingly significant temperature difference across the Cascades (10-20F warmer west of the Cascade Crest). As a result. Areas west of the Cascade Crest could have freezing levels in the 6,000-10,000 ft range by late 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 Night Mostly cloudy in the evening with partial clearing overnight. A slight chance of a rain or snow shower.
Monday Partly cloudy.
Sunday Night Mostly cloudy with isolated rain and snow showers.
Monday Mostly cloudy in the morning with more sun than clouds in the afternoon.
Sunday Night Mostly cloudy with isolated rain and snow showers.
Monday Mostly cloudy in the morning with partial cloud cover in the afternoon.
Sunday Night Mostly cloudy with isolated rain and snow showers.
Monday Mostly cloudy in the morning with partial cloud cover in the afternoon.
Sunday Night Mostly cloudy with isolated rain and snow showers. Light ridgeline and light W or variable winds at the Pass.
Monday Mostly cloudy in the morning, then becoming partly cloudy. Light ridgeline with light E winds developing at the Pass.
Sunday Night Mostly cloudy with isolated rain and snow showers. Light ridgeline and light W or variable winds at the Pass.
Monday Mostly cloudy in the morning, then becoming partly cloudy. Light ridgeline with light E winds developing at the Pass.
Sunday Night Partly cloudy with a chance of isolated rain or snow showers near the Cascade Crest.
Monday Partly cloudy in the morning, then becoming mostly sunny.
Sunday Night Partly cloudy with a chance of isolated rain or snow showers near the Cascade Crest.
Monday Partly cloudy in the morning, then becoming mostly sunny.
Sunday Night Partly cloudy with isolated rain and snow showers.
Monday Partly cloudy in the morning, then becoming mostly sunny.
Sunday Night Decreasing light rain and snow showers. Light to moderate ridgeline winds decreasing.
Monday Mostly cloudy with a chance of an isolated rain or snow shower.

Issued: 2:45 PM PST Sunday, December 10, 2023

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

Issued: 2:45 PM PST Sunday, December 10, 2023

Snow Level (ft)

Sunday Evening Sunday Night Monday Morning Monday Afternoon* Monday Evening* Monday Night* Tuesday Morning* Tuesday Afternoon*
Olympics 6000' 4500' 4500' 4500' 4500' 4500' 5500' 9000'
West North 5000' 5000' 4500' 5000' 4000' 3000' 3000' 7000'
West Central 5000' 5500' 5000' 5000' 4500' 3000' 3000' 6500'
West South 5500' 5500' 5000' 5000' 4500' 3500' 3500' 7000'
Stevens Pass 5000' 5500' 5000' 5000' 4000' 2500' 2500' 4500'
Snoqualmie Pass 5500' 5500' 5000' 5000' 4500' 3500' 3500' 6500'
East North 4500' 5500' 5000' 5000' 3000' 1500' 1500' 4000'
East Central 5500' 5500' 5000' 5000' 4500' 3000' 3500' 4000'
East South 5500' 6000' 5000' 5000' 5000' 4000' 4000' 5000'
Mt. Hood 6500' 7000' 5500' 6000' 5500' 5000' 5000' 6500'
Olympics Elevation
Sunday Evening 6000'
Sunday Night 4500'
Monday Morning 4500'
Monday Afternoon* 4500'
Monday Evening* 4500'
Monday Night* 4500'
Tuesday Morning* 5500'
Tuesday Afternoon* 9000'
West North Elevation
Sunday Evening 5000'
Sunday Night 5000'
Monday Morning 4500'
Monday Afternoon* 5000'
Monday Evening* 4000'
Monday Night* 3000'
Tuesday Morning* 3000'
Tuesday Afternoon* 7000'
West Central Elevation
Sunday Evening 5000'
Sunday Night 5500'
Monday Morning 5000'
Monday Afternoon* 5000'
Monday Evening* 4500'
Monday Night* 3000'
Tuesday Morning* 3000'
Tuesday Afternoon* 6500'
West South Elevation
Sunday Evening 5500'
Sunday Night 5500'
Monday Morning 5000'
Monday Afternoon* 5000'
Monday Evening* 4500'
Monday Night* 3500'
Tuesday Morning* 3500'
Tuesday Afternoon* 7000'
Stevens Pass Elevation
Sunday Evening 5000'
Sunday Night 5500'
Monday Morning 5000'
Monday Afternoon* 5000'
Monday Evening* 4000'
Monday Night* 2500'
Tuesday Morning* 2500'
Tuesday Afternoon* 4500'
Snoqualmie Pass Elevation
Sunday Evening 5500'
Sunday Night 5500'
Monday Morning 5000'
Monday Afternoon* 5000'
Monday Evening* 4500'
Monday Night* 3500'
Tuesday Morning* 3500'
Tuesday Afternoon* 6500'
East North Elevation
Sunday Evening 4500'
Sunday Night 5500'
Monday Morning 5000'
Monday Afternoon* 5000'
Monday Evening* 3000'
Monday Night* 1500'
Tuesday Morning* 1500'
Tuesday Afternoon* 4000'
East Central Elevation
Sunday Evening 5500'
Sunday Night 5500'
Monday Morning 5000'
Monday Afternoon* 5000'
Monday Evening* 4500'
Monday Night* 3000'
Tuesday Morning* 3500'
Tuesday Afternoon* 4000'
East South Elevation
Sunday Evening 5500'
Sunday Night 6000'
Monday Morning 5000'
Monday Afternoon* 5000'
Monday Evening* 5000'
Monday Night* 4000'
Tuesday Morning* 4000'
Tuesday Afternoon* 5000'
Mt. Hood Elevation
Sunday Evening 6500'
Sunday Night 7000'
Monday Morning 5500'
Monday Afternoon* 6000'
Monday Evening* 5500'
Monday Night* 5000'
Tuesday Morning* 5000'
Tuesday Afternoon* 6500'

Issued: 2:45 PM PST Sunday, December 10, 2023

5000' Temperatures (°F)

Sunday Night Monday
Max / Min Max / Min
Olympics 30 / 26 30 / 26
West North 34 / 30 33 / 28
West Central 34 / 29 31 / 28
West South 35 / 31 34 / 28
Stevens Pass 34 / 28 32 / 28
Snoqualmie Pass 35 / 29 32 / 28
East North 33 / 29 32 / 28
East Central 34 / 28 31 / 28
East South 34 / 29 34 / 29
Mt. Hood 37 / 35 35 / 31
Olympics 5000' Temperature Forecast
(Max / Min)
Sunday Night 30 / 26
Monday 30 / 26
West North 5000' Temperature Forecast
(Max / Min)
Sunday Night 34 / 30
Monday 33 / 28
West Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 34 / 29
Monday 31 / 28
West South 5000' Temperature Forecast
(Max / Min)
Sunday Night 35 / 31
Monday 34 / 28
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 34 / 28
Monday 32 / 28
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 35 / 29
Monday 32 / 28
East North 5000' Temperature Forecast
(Max / Min)
Sunday Night 33 / 29
Monday 32 / 28
East Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 34 / 28
Monday 31 / 28
East South 5000' Temperature Forecast
(Max / Min)
Sunday Night 34 / 29
Monday 34 / 29
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Sunday Night 37 / 35
Monday 35 / 31

Issued: 2:45 PM PST Sunday, December 10, 2023

Ridgeline Winds (mph)

Sunday Evening Sunday Night Monday Morning Monday Afternoon
Olympics WSW 0-10 E 0-10 E 0-10 ESE 0-10
West North WSW 5-15 SSW 0-10 ESE 0-10 SE 0-10
West Central WSW 5-15 SW 0-10 S 0-10 ESE 5-15
West South SW 0-10 WSW 0-10 S 0-10 SE 0-10
Stevens Pass W 5-15 W 0-10 E 0-10 ESE 5-15
Snoqualmie Pass W 5-15 W 0-10 SE 0-10 ESE 5-15
East North WSW 5-15 W 5-15 NE 0-10 SE 0-10
East Central W 10-20 W 5-15 E 0-10 ESE 5-15
East South W 5-15 W 5-15 SSE 0-10 ESE 0-10
Mt. Hood WSW 10-20 WSW 5-15 SW 0-10 SSE 0-10
Olympics Ridgeline Winds (mph)
Sunday Evening WSW 0-10
Sunday Night E 0-10
Monday Morning E 0-10
Monday Afternoon ESE 0-10
West North Ridgeline Winds (mph)
Sunday Evening WSW 5-15
Sunday Night SSW 0-10
Monday Morning ESE 0-10
Monday Afternoon SE 0-10
West Central Ridgeline Winds (mph)
Sunday Evening WSW 5-15
Sunday Night SW 0-10
Monday Morning S 0-10
Monday Afternoon ESE 5-15
West South Ridgeline Winds (mph)
Sunday Evening SW 0-10
Sunday Night WSW 0-10
Monday Morning S 0-10
Monday Afternoon SE 0-10
Stevens Pass Ridgeline Winds (mph)
Sunday Evening W 5-15
Sunday Night W 0-10
Monday Morning E 0-10
Monday Afternoon ESE 5-15
Snoqualmie Pass Ridgeline Winds (mph)
Sunday Evening W 5-15
Sunday Night W 0-10
Monday Morning SE 0-10
Monday Afternoon ESE 5-15
East North Ridgeline Winds (mph)
Sunday Evening WSW 5-15
Sunday Night W 5-15
Monday Morning NE 0-10
Monday Afternoon SE 0-10
East Central Ridgeline Winds (mph)
Sunday Evening W 10-20
Sunday Night W 5-15
Monday Morning E 0-10
Monday Afternoon ESE 5-15
East South Ridgeline Winds (mph)
Sunday Evening W 5-15
Sunday Night W 5-15
Monday Morning SSE 0-10
Monday Afternoon ESE 0-10
Mt. Hood Ridgeline Winds (mph)
Sunday Evening WSW 10-20
Sunday Night WSW 5-15
Monday Morning SW 0-10
Monday Afternoon SSE 0-10

Issued: 2:45 PM PST Sunday, December 10, 2023

Extended Weather Synopsis

A weakening frontal system shifts the ridge of high-pressure east of the region on Wednesday, allowing clouds to increase along with light SW winds. Light rain and snow arrive Wednesday night through Thursday morning. Weak ridging re-develops late in the day.

Extended Snow Level (ft)

Tuesday Night* Wednesday * Wednesday Night* Thursday *
West North 5000' 6500' 4000' 3000'
Snoqualmie Pass 4500' 5500' 4000' 3500'
Mt. Hood 6500' 8000' 8500' 7000'
West North Elevation
Tuesday Night* 5000'
Wednesday * 6500'
Wednesday Night* 4000'
Thursday * 3000'
Snoqualmie Pass Elevation
Tuesday Night* 4500'
Wednesday * 5500'
Wednesday Night* 4000'
Thursday * 3500'
Mt. Hood Elevation
Tuesday Night* 6500'
Wednesday * 8000'
Wednesday Night* 8500'
Thursday * 7000'

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

Previous forecast from Dec 10, 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’.