Issued: 4:57 PM PST Sunday, January 31, 2021
by Dennis D'Amico

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

Weather Synopsis

1655: Updated several precipitation forecasts for tonight and Monday. 

A quasi-stationary frontal boundary has slowly drifted past the Olympics and into the Puget sound today with heavy precipitation for the Olympics and Mt Baker area and much lighter amounts just about everywhere else. New disturbances forming along this frontal boundary or baroclinic zone will cause it to shift back and forth over the next 24 hours. The frontal boundary extends from a low pressure complex positioned well off of northern Vancouver Island. 

The current frontal boundary should stay in its current position through this evening. A warm frontal feature will begin lifting north overnight, shifting the precipitation axis back to the west and increasing ridgeline winds. The trailing occluded front will slowly side inland tomorrow with a similar breakdown for precipitation distribution regionally as what we've seen today. Snow levels will be a moving target but suffice to say this is not a cold storm with snow levels generally near or above 4000'. 

A shortwave trough will finally kick the frontal boundary through Monday night with more widespread precipitation across the area and a shift from S-SE winds to W-SW. Post frontal showers will ensue late Monday night through Tuesday with a return to a familiar precipitation pattern favoring the west slopes of the Cascades and Mt Hood.  Snow levels will start to lower behind the front later Monday night as well. 

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 to occasionally moderate rain and snow.
Monday Light to occasionally moderate rain and snow. Strong ridgeline winds.
Sunday Night Moderate to heavy rain and snow. Strong ridgeline winds.
Monday Moderate to heavy rain and snow. Strong ridgeline winds decreasing in the afternoon.
Sunday Night Light to moderate rain and snow. Strong ridgeline winds.
Monday Light to moderate rain and snow. Strong ridgeline winds decreasing in the afternoon.
Sunday Night Light to occasionally moderate rain and snow. Lighter White Pass area. Strong ridgeline winds.
Monday Light to occasionally moderate rain and snow. Lighter White Pass area. Strong ridgeline winds decreasing in the afternoon.
Sunday Night Cloudy with periods of light rain and snow. Light east winds at Pass level.
Monday Cloudy with periods of light rain and snow. Light east winds at Pass level.
Sunday Night Cloudy with periods of light rain and snow. Light east winds at Pass level.
Monday Cloudy with periods of light rain and snow. Light east winds at Pass level.
Sunday Night Light to occasionally moderate rain and snow.
Monday Light to occasionally moderate rain and snow.
Sunday Night Light to occasionally moderate rain and snow.
Monday Light to occasionally moderate rain and snow.
Sunday Night Light to occasionally moderate rain and snow.
Monday Light to occasionally moderate rain and snow.
Sunday Night Light to occasionally moderate rain and snow.
Monday Light to moderate rain and snow.

Issued: 4:57 PM PST Sunday, January 31, 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 0.50 - 0.75 0.50 - 0.75 0.25 LT 0.25
Mt Baker Ski Area 1.00 - 1.50 1.00 - 1.50 0.75 -1.00 0.25 - 0.50
Mt. Loop - Barlow Pass 0.50 0.50 0.50 - 0.75 0.25
Stevens Pass LT 0.25 LT 0.25 0.25 LT 0.25
Snoqualmie Pass LT 0.25 LT 0.25 0.25 - 0.50 LT 0.25
Crystal Mt 0.50 0.25 - 0.50 0.25 - 0.50 LT 0.25
Paradise 0.25 - 0.50 0.25 - 0.50 0.50 0.25 - 0.50
White Pass 0.25 0.25 0.25 - 0.50 0.25
Washington Pass 0.25 0.25 0.25 LT 0.10
Mission Ridge 0.25 - 0.50 0.25 0.25 LT 0.10
Salmon la Sac - Gallagher Head 0.25 0.25 0.25 LT 0.25
Tieton River - Darland Mt. 0.25 0.25 0.25 LT 0.10
Mt Hood Meadows 0.25 - 0.50 0.50 LT 0.25 0.25
Timberline 0.25 - 0.50 0.50 - 0.75 0.25 0.25 - 0.50
Hurricane Ridge Precipitation (in)
Sunday Night 0.50 - 0.75
Monday 0.50 - 0.75
Monday Night 0.25
Tuesday LT 0.25
Mt Baker Ski Area Precipitation (in)
Sunday Night 1.00 - 1.50
Monday 1.00 - 1.50
Monday Night 0.75 -1.00
Tuesday 0.25 - 0.50
Mt. Loop - Barlow Pass Precipitation (in)
Sunday Night 0.50
Monday 0.50
Monday Night 0.50 - 0.75
Tuesday 0.25
Stevens Pass Precipitation (in)
Sunday Night LT 0.25
Monday LT 0.25
Monday Night 0.25
Tuesday LT 0.25
Snoqualmie Pass Precipitation (in)
Sunday Night LT 0.25
Monday LT 0.25
Monday Night 0.25 - 0.50
Tuesday LT 0.25
Crystal Mt Precipitation (in)
Sunday Night 0.50
Monday 0.25 - 0.50
Monday Night 0.25 - 0.50
Tuesday LT 0.25
Paradise Precipitation (in)
Sunday Night 0.25 - 0.50
Monday 0.25 - 0.50
Monday Night 0.50
Tuesday 0.25 - 0.50
White Pass Precipitation (in)
Sunday Night 0.25
Monday 0.25
Monday Night 0.25 - 0.50
Tuesday 0.25
Washington Pass Precipitation (in)
Sunday Night 0.25
Monday 0.25
Monday Night 0.25
Tuesday LT 0.10
Mission Ridge Precipitation (in)
Sunday Night 0.25 - 0.50
Monday 0.25
Monday Night 0.25
Tuesday LT 0.10
Salmon la Sac - Gallagher Head Precipitation (in)
Sunday Night 0.25
Monday 0.25
Monday Night 0.25
Tuesday LT 0.25
Tieton River - Darland Mt. Precipitation (in)
Sunday Night 0.25
Monday 0.25
Monday Night 0.25
Tuesday LT 0.10
Mt Hood Meadows Precipitation (in)
Sunday Night 0.25 - 0.50
Monday 0.50
Monday Night LT 0.25
Tuesday 0.25
Timberline Precipitation (in)
Sunday Night 0.25 - 0.50
Monday 0.50 - 0.75
Monday Night 0.25
Tuesday 0.25 - 0.50

Issued: 4:57 PM PST Sunday, January 31, 2021

Snow Level (ft)

Sunday Evening* Sunday Night* Monday Morning* Monday Afternoon* Monday Evening Monday Night Tuesday Morning Tuesday Afternoon
Olympics 3000' 3500' 4500' 5000' 3500' 2000' 2000' 2500'
West North 4000' 4000' 3500' 4000' 3500' 2000' 2000' 2500'
West Central 4000' 4500' 4500' 4500' 3500' 2000' 2000' 2500'
West South 5000' 5500' 5500' 5000' 4500' 2000' 2000' 2500'
Stevens Pass 4000' 4500' 4500' 4500' 4000' 2000' 2000' 2500'
Snoqualmie Pass 4000' 5000' 5000' 5000' 4500' 2000' 2000' 2500'
East North 3500' 3500' 4000' 4000' 3500' 2000' 2000' 2500'
East Central 3500' 4000' 4500' 4000' 4000' 2500' 2500' 2500'
East South 4500' 4500' 4500' 4500' 4000' 2500' 2500' 2500'
Mt. Hood 6000' 6000' 6000' 5500' 5000' 3500' 3000' 3000'
Olympics Elevation
Sunday Evening* 3000'
Sunday Night* 3500'
Monday Morning* 4500'
Monday Afternoon* 5000'
Monday Evening 3500'
Monday Night 2000'
Tuesday Morning 2000'
Tuesday Afternoon 2500'
West North Elevation
Sunday Evening* 4000'
Sunday Night* 4000'
Monday Morning* 3500'
Monday Afternoon* 4000'
Monday Evening 3500'
Monday Night 2000'
Tuesday Morning 2000'
Tuesday Afternoon 2500'
West Central Elevation
Sunday Evening* 4000'
Sunday Night* 4500'
Monday Morning* 4500'
Monday Afternoon* 4500'
Monday Evening 3500'
Monday Night 2000'
Tuesday Morning 2000'
Tuesday Afternoon 2500'
West South Elevation
Sunday Evening* 5000'
Sunday Night* 5500'
Monday Morning* 5500'
Monday Afternoon* 5000'
Monday Evening 4500'
Monday Night 2000'
Tuesday Morning 2000'
Tuesday Afternoon 2500'
Stevens Pass Elevation
Sunday Evening* 4000'
Sunday Night* 4500'
Monday Morning* 4500'
Monday Afternoon* 4500'
Monday Evening 4000'
Monday Night 2000'
Tuesday Morning 2000'
Tuesday Afternoon 2500'
Snoqualmie Pass Elevation
Sunday Evening* 4000'
Sunday Night* 5000'
Monday Morning* 5000'
Monday Afternoon* 5000'
Monday Evening 4500'
Monday Night 2000'
Tuesday Morning 2000'
Tuesday Afternoon 2500'
East North Elevation
Sunday Evening* 3500'
Sunday Night* 3500'
Monday Morning* 4000'
Monday Afternoon* 4000'
Monday Evening 3500'
Monday Night 2000'
Tuesday Morning 2000'
Tuesday Afternoon 2500'
East Central Elevation
Sunday Evening* 3500'
Sunday Night* 4000'
Monday Morning* 4500'
Monday Afternoon* 4000'
Monday Evening 4000'
Monday Night 2500'
Tuesday Morning 2500'
Tuesday Afternoon 2500'
East South Elevation
Sunday Evening* 4500'
Sunday Night* 4500'
Monday Morning* 4500'
Monday Afternoon* 4500'
Monday Evening 4000'
Monday Night 2500'
Tuesday Morning 2500'
Tuesday Afternoon 2500'
Mt. Hood Elevation
Sunday Evening* 6000'
Sunday Night* 6000'
Monday Morning* 6000'
Monday Afternoon* 5500'
Monday Evening 5000'
Monday Night 3500'
Tuesday Morning 3000'
Tuesday Afternoon 3000'

Issued: 4:57 PM PST Sunday, January 31, 2021

5000' Temperatures (°F)

Sunday Night Monday
Max / Min Max / Min
Olympics 29 / 24 32 / 28
West North 30 / 27 32 / 29
West Central 31 / 30 32 / 30
West South 33 / 32 34 / 32
Stevens Pass 31 / 30 33 / 30
Snoqualmie Pass 31 / 30 31 / 30
East North 29 / 28 32 / 29
East Central 31 / 30 32 / 31
East South 32 / 30 33 / 30
Mt. Hood 34 / 33 34 / 32
Olympics 5000' Temperature Forecast
(Max / Min)
Sunday Night 29 / 24
Monday 32 / 28
West North 5000' Temperature Forecast
(Max / Min)
Sunday Night 30 / 27
Monday 32 / 29
West Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 30
Monday 32 / 30
West South 5000' Temperature Forecast
(Max / Min)
Sunday Night 33 / 32
Monday 34 / 32
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 30
Monday 33 / 30
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 30
Monday 31 / 30
East North 5000' Temperature Forecast
(Max / Min)
Sunday Night 29 / 28
Monday 32 / 29
East Central 5000' Temperature Forecast
(Max / Min)
Sunday Night 31 / 30
Monday 32 / 31
East South 5000' Temperature Forecast
(Max / Min)
Sunday Night 32 / 30
Monday 33 / 30
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Sunday Night 34 / 33
Monday 34 / 32

Issued: 4:57 PM PST Sunday, January 31, 2021

Ridgeline Winds (mph)

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

Issued: 4:57 PM PST Sunday, January 31, 2021

Extended Weather Synopsis

A couple of fast-moving systems will move through the area Wednesday and again Thursday in NW flow aloft. The Wednesday system looks colder but drier, similar to the pattern of last week with a weak low pressure system off the Washington/Oregon coast. The system for Thursday may bring a more moderate shot of snow and wind. 

Extended Snow Level (ft)

Tuesday Night Wednesday Wednesday Night Thursday
West North 1500' 2000' 1000' 2000'
Snoqualmie Pass 1500' 2500' 1000' 2000'
Mt. Hood 2000' 3000' 1500' 2500'
West North Elevation
Tuesday Night 1500'
Wednesday 2000'
Wednesday Night 1000'
Thursday 2000'
Snoqualmie Pass Elevation
Tuesday Night 1500'
Wednesday 2500'
Wednesday Night 1000'
Thursday 2000'
Mt. Hood Elevation
Tuesday Night 2000'
Wednesday 3000'
Wednesday Night 1500'
Thursday 2500'

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

Previous forecast from Jan 31, 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’.