Issued: 2:51 PM PST Sunday, January 3, 2021
by Robert Hahn

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

Weather Synopsis

Sunday evening, another storm develops off the Oregon coast, lifting a warm front over our region Sunday night with rising snow levels, ESE flow, and increasing moderate to heavy rain and snow starting in the Mt. Hood area in the evening and spreading to other areas overnight. E flow at low-levels will help snow totals along the E slopes and should keep Snoqualmie Pass as all snow until at least 10 AM on Monday morning. Late morning as the cold pool east of the Cascades gets scoured by southerly winds and weakens we're forecasting a rain/snow mix at pass level until the cold front passes E to W through the Cascades around noon. Precipitation should become showery with WSW flow and a shortwave trough moving into the region. Models indicate some strong convergence may develop in the mountain loop area Monday afternoon and is expected to slide southward toward the central Cascade Passes in the evening. Precipitation doesn't shut fully shut off as weak ridging moves in late Monday night. The storm should bring 6-20" of snow to many locations across the Cascades with the most expected at Mt. Baker and Paradise, but with E flow for much of the storm, many locations on the east slopes of the Cascades may pick up around 1 ft of snow.

The next system approaches the area on Tuesday, bringing the region a cloudy day with increasing rain and snow arriving late in the day. Expect E low-level flow increasing and keeping the passes cool.

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 Cloudy in the evening with moderate rain and snow developing overnight.
Monday Moderate rain and snow early, then light showers activity increasing in the afternoon.
Sunday Night Cloudy in the evening with moderate then heavy rain and snow developing in the early morning hours.
Monday Heavy rain and snow becoming light to moderate showers in the afternoon.
Sunday Night Cloudy in the evening with moderate then heavy rain and snow developing after midnight.
Monday Heavy rain and snow becoming light to moderate showers and convergence in the afternoon.
Sunday Night Cloudy in the evening with moderate then heavy rain and snow developing overnight.
Monday Heavy rain and snow becoming light to moderate showers in the afternoon.
Sunday Night Cloudy in the evening with moderate rain and snow developing after midnight. Light E winds at pass level.
Monday Moderate snow changing to light rain/snow showers and convergence possible in the afternoon. Light E flow switching W in the afternoon.
Sunday Night Cloudy in the evening with moderate rain and snow developing after midnight. Light E winds at pass level becoming moderate overnight.
Monday Moderate snow changing mixing with rain in the late morning, then light rain/snow showers possible in the afternoon. Moderate E flow at low-levels in the morning switching W at noon and becoming light.
Sunday Night Cloudy in the evening with light to moderate snow developing after midnight.
Monday Light to moderate snow decreasing late in the day.
Sunday Night Cloudy in the evening with moderate snow developing after midnight.
Monday Moderate snow in the morning, then light to moderate rain and snow showers in the afternoon.
Sunday Night Cloudy in the evening with moderate rain and snow developing overnight.
Monday Moderate rain and snow in the morning, then light to moderate rain and snow showers in the afternoon.
Sunday Night Moderate to heavy rain and snow. Strong wind gusts in the alpine.
Monday Moderate to heavy rain and snow in the morning becoming light showers in the afternoon.

Issued: 2:51 PM PST Sunday, January 3, 2021

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

Issued: 2:51 PM PST Sunday, January 3, 2021

Snow Level (ft)

Sunday Evening* Sunday Night* Monday Morning* Monday Afternoon Monday Evening Monday Night Tuesday Morning* Tuesday Afternoon*
Olympics 2500' 4500' 4000' 3000' 2500' 1500' 2000' 3000'
West North 2500' 1500' 2000' 2500' 2500' 1500' 1000' 2000'
West Central 2500' 2000' 2500' 2500' 2000' 2000' 1500' 2500'
West South 2500' 3500' 4000' 4000' 2500' 2000' 1000' 2500'
Stevens Pass 2500' 1500' 2000' 3000' 2500' 2000' 1500' 2500'
Snoqualmie Pass 3000' 2500' 3000' 3500' 2500' 2000' 1500' 2500'
East North 1500' 1000' 1500' 3000' 3000' 1500' 0 2000'
East Central 2500' 2000' 3000' 3500' 2500' 1500' 1000' 2000'
East South 2500' 3500' 4000' 4000' 3000' 2000' 1000' 2500'
Mt. Hood 5000' 5000' 5500' 4000' 3000' 2500' 1500' 3500'
Olympics Elevation
Sunday Evening* 2500'
Sunday Night* 4500'
Monday Morning* 4000'
Monday Afternoon 3000'
Monday Evening 2500'
Monday Night 1500'
Tuesday Morning* 2000'
Tuesday Afternoon* 3000'
West North Elevation
Sunday Evening* 2500'
Sunday Night* 1500'
Monday Morning* 2000'
Monday Afternoon 2500'
Monday Evening 2500'
Monday Night 1500'
Tuesday Morning* 1000'
Tuesday Afternoon* 2000'
West Central Elevation
Sunday Evening* 2500'
Sunday Night* 2000'
Monday Morning* 2500'
Monday Afternoon 2500'
Monday Evening 2000'
Monday Night 2000'
Tuesday Morning* 1500'
Tuesday Afternoon* 2500'
West South Elevation
Sunday Evening* 2500'
Sunday Night* 3500'
Monday Morning* 4000'
Monday Afternoon 4000'
Monday Evening 2500'
Monday Night 2000'
Tuesday Morning* 1000'
Tuesday Afternoon* 2500'
Stevens Pass Elevation
Sunday Evening* 2500'
Sunday Night* 1500'
Monday Morning* 2000'
Monday Afternoon 3000'
Monday Evening 2500'
Monday Night 2000'
Tuesday Morning* 1500'
Tuesday Afternoon* 2500'
Snoqualmie Pass Elevation
Sunday Evening* 3000'
Sunday Night* 2500'
Monday Morning* 3000'
Monday Afternoon 3500'
Monday Evening 2500'
Monday Night 2000'
Tuesday Morning* 1500'
Tuesday Afternoon* 2500'
East North Elevation
Sunday Evening* 1500'
Sunday Night* 1000'
Monday Morning* 1500'
Monday Afternoon 3000'
Monday Evening 3000'
Monday Night 1500'
Tuesday Morning* 0'
Tuesday Afternoon* 2000'
East Central Elevation
Sunday Evening* 2500'
Sunday Night* 2000'
Monday Morning* 3000'
Monday Afternoon 3500'
Monday Evening 2500'
Monday Night 1500'
Tuesday Morning* 1000'
Tuesday Afternoon* 2000'
East South Elevation
Sunday Evening* 2500'
Sunday Night* 3500'
Monday Morning* 4000'
Monday Afternoon 4000'
Monday Evening 3000'
Monday Night 2000'
Tuesday Morning* 1000'
Tuesday Afternoon* 2500'
Mt. Hood Elevation
Sunday Evening* 5000'
Sunday Night* 5000'
Monday Morning* 5500'
Monday Afternoon 4000'
Monday Evening 3000'
Monday Night 2500'
Tuesday Morning* 1500'
Tuesday Afternoon* 3500'

Issued: 2:51 PM PST Sunday, January 3, 2021

5000' Temperatures (°F)

Sunday Night Monday
Max / Min Max / Min
Olympics 31 / 28 32 / 27
West North 28 / 26 29 / 27
West Central 29 / 27 30 / 27
West South 31 / 28 31 / 28
Stevens Pass 28 / 27 30 / 27
Snoqualmie Pass 30 / 28 31 / 28
East North 26 / 21 30 / 24
East Central 29 / 26 31 / 27
East South 31 / 27 31 / 28
Mt. Hood 32 / 31 33 / 29
Olympics 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 28
Monday 32 / 27
West North 5000' Temperature Forecast
(Max / Min)
Sunday Night 28 / 26
Monday 29 / 27
West Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 29 / 27
Monday 30 / 27
West South 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 28
Monday 31 / 28
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 28 / 27
Monday 30 / 27
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 30 / 28
Monday 31 / 28
East North 5000' Temperature Forecast
(Max / Min)
Sunday Night 26 / 21
Monday 30 / 24
East Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 29 / 26
Monday 31 / 27
East South 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 27
Monday 31 / 28
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Sunday Night 32 / 31
Monday 33 / 29

Issued: 2:51 PM PST Sunday, January 3, 2021

Ridgeline Winds (mph)

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

Issued: 2:51 PM PST Sunday, January 3, 2021

Extended Weather Synopsis

Another low in the Gulf of Alaska pushes a moderately strong cold front through the region Tuesday night into Wednesday morning. Moisture likely lingers into the afternoon for the Mt. Hood area as a shortwave trough moves into the region. Some moisture may try to work northward Wednesday evening before a shortwave ridge brings clearing skies Wednesday night and a rare mostly sunny day on Thursday. Models diverge Thursday night into Friday. The European model brings a frontal system into the region. The GFS keeps a trough and associated front further offshore, with clear skies and a period of strong low-level E flow into Friday.

Extended Snow Level (ft)

Tuesday Night* Wednesday * Wednesday Night Thursday *
West North 2000' 2500' 2500' 3500'
Snoqualmie Pass 2500' 2500' 3000' 3000'
Mt. Hood 5000' 3500' 3500' 5000'
West North Elevation
Tuesday Night* 2000'
Wednesday * 2500'
Wednesday Night 2500'
Thursday * 3500'
Snoqualmie Pass Elevation
Tuesday Night* 2500'
Wednesday * 2500'
Wednesday Night 3000'
Thursday * 3000'
Mt. Hood Elevation
Tuesday Night* 5000'
Wednesday * 3500'
Wednesday Night 3500'
Thursday * 5000'

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

Previous forecast from Jan 3, 2021

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’.