Issued: 2:01 PM PST Tuesday, December 27, 2022
by Dennis D'Amico

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

Weather Synopsis

A low pressure system will push inland this afternoon.  A period of heavy precipitation is on tap for the rest of Tuesday afternoon for the Mt Hood and south Washington Cascades and then the central Cascades this evening. As the low shifts to the east side of the Cascades, a switch from S-SW to westerly winds will follow.  Onshore flow plus a low-level jet south of the low will help hammer extreme westerly winds, currently occurring in the Mt Hood area this afternoon, into the south Washington Cascades in the evening. The strongest winds are expected to reach as far north as Stevens Pass and the Hwy 2 East corridor this evening.   

Heavy showers will continue in post-frontal westerly flow Tuesday night, aided by areas of convergence that eventually shift the heaviest showers over the Washington Cascades north into the Mountain Loop and Whatcom county.  Snow levels will slowly overnight, settling around 3000' before dawn across the region. Winds will peak early this evening but will stay strong all night. With the cooling trend, mid and upper elevations on both sides of the Cascades stand the best chance of picking up over a foot of snow through tomorrow morning. 

Showers will continue along the west slopes of the Cascades on Wednesday but should become more scattered and lighter by the afternoon. The same downward trend can be said for the westerly winds. 

An upper level ridge offshore will pass over the area Wednesday night and east of the Cascades on Thursday. We should see a mostly dry Wednesday night.  A weak N-S frontal system will approach on Thursday, bringing generally light precipitation for most areas. The Mt Hood area may see relatively heftier precipitation totals, as well as higher snow levels since they sit closer to the jet. 

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
Tuesday Night Moderate rain and snow becoming light rain and snow showers in the evening. Strong winds easing after midnight.
Wednesday Cloudy with scattered light rain and snow showers.
Tuesday Night Moderate to occasionally heavy rain and snow showers. Strong winds easing after midnight.
Wednesday Light to occasionally moderate rain and snow showers in the morning, then light and scattered showers in the afternoon.
Tuesday Night Stormy with moderate to occasionally heavy rain and snow showers. Strong winds.
Wednesday Light to occasionally moderate rain and snow showers in the morning, then lighter showers in the afternoon.
Tuesday Night Stormy with moderate to occasionally heavy rain and snow showers tapering off after midnight. Strong to extreme winds.
Wednesday Light to occasionally moderate rain and snow showers in the morning, then lighter showers in the afternoon. Strong winds decreasing during the day.
Tuesday Night Stormy with increasing moderate to occasionally heavy rain and snow showers in the evening. Strong W winds at Pass level and ridgeline.
Wednesday Light to occasionally moderate rain and snow showers in the morning, then lighter showers in the afternoon. Moderate to strong W winds at Pass and ridgeline slowly decreasing during the day.
Tuesday Night Stormy with increasing moderate to occasionally heavy rain and snow showers in the evening. Strong W winds at Pass level and ridgeline.
Wednesday Light to occasionally moderate rain and snow showers in the morning, then lighter showers in the afternoon. Strong W winds at Pass and ridgeline slowly decreasing during the day.
Tuesday Night Light to occasionally moderate rain and snow showers. Winds becoming moderate to strong.
Wednesday Light rain and snow showers, occasionally moderate near the Cascade crest in the morning, becoming scattered light showers in the afternoon.
Tuesday Night Stormy with moderate to occasionally heavy rain and snow showers, heaviest near the Cascade crest, tapering off late. Strong to extreme winds.
Wednesday Light rain and snow showers, occasionally moderate near the Cascade crest in the morning, becoming scattered light showers in the afternoon. Strong winds slowly decreasing during the day.
Tuesday Night Stormy with moderate to occasionally heavy rain and snow showers, heaviest near the Cascade crest, tapering off after midnight. Extreme winds.
Wednesday Light rain and snow showers, occasionally moderate near the Cascade crest in the morning, becoming scattered light showers in the afternoon. Strong winds slowly decreasing during the day.
Tuesday Night Stormy with moderate to heavy rain and snow showers. Extreme winds.
Wednesday Moderate rain and snow showers in the morning, becoming lighter in the afternoon. Strong winds slowly decreasing during the day.

Issued: 2:01 PM PST Tuesday, December 27, 2022

Precipitation (in)

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

Issued: 2:01 PM PST Tuesday, December 27, 2022

Snow Level (ft)

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

Issued: 2:01 PM PST Tuesday, December 27, 2022

5000' Temperatures (°F)

Tuesday Night Wednesday
Max / Min Max / Min
Olympics 31 / 21 27 / 22
West North 31 / 24 27 / 22
West Central 30 / 23 27 / 23
West South 29 / 22 27 / 23
Stevens Pass 30 / 22 27 / 23
Snoqualmie Pass 29 / 21 27 / 22
East North 29 / 23 27 / 20
East Central 29 / 22 27 / 22
East South 28 / 22 28 / 23
Mt. Hood 27 / 23 29 / 25
Olympics 5000' Temperature Forecast
(Max / Min)
Tuesday Night 31 / 21
Wednesday 27 / 22
West North 5000' Temperature Forecast
(Max / Min)
Tuesday Night 31 / 24
Wednesday 27 / 22
West Central 5000' Temperature Forecast
(Max / Min)
Tuesday Night 30 / 23
Wednesday 27 / 23
West South 5000' Temperature Forecast
(Max / Min)
Tuesday Night 29 / 22
Wednesday 27 / 23
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Tuesday Night 30 / 22
Wednesday 27 / 23
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Tuesday Night 29 / 21
Wednesday 27 / 22
East North 5000' Temperature Forecast
(Max / Min)
Tuesday Night 29 / 23
Wednesday 27 / 20
East Central 5000' Temperature Forecast
(Max / Min)
Tuesday Night 29 / 22
Wednesday 27 / 22
East South 5000' Temperature Forecast
(Max / Min)
Tuesday Night 28 / 22
Wednesday 28 / 23
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Tuesday Night 27 / 23
Wednesday 29 / 25

Issued: 2:01 PM PST Tuesday, December 27, 2022

Ridgeline Winds (mph)

Tuesday Evening Tuesday Night Wednesday Morning Wednesday Afternoon
Olympics W 25-35 WSW 20-30 WSW 15-25 WSW 5-15
West North SW 15-25 WSW 25-35 WSW 10-20 SW 5-15
West Central SW 15-25 W 20-30 W 10-20 W 5-15
West South WSW 40-55 W 30-40 W 25-35 W 15-25
Stevens Pass WSW 20-30 W 25-35 W 15-25 W 10-20
Snoqualmie Pass W 40-55 W 35-50 W 25-35 W 15-25
East North WSW 15-25 WSW 25-35 W 20-30 W 10-20
East Central W 40-55 W 40-55 W 35-50 W 15-25
East South W 45-65 W 35-50 W 30-40 W 15-25
Mt. Hood W 55-75 W 40-55 W 35-50 W 30-40
Olympics Ridgeline Winds (mph)
Tuesday Evening W 25-35
Tuesday Night WSW 20-30
Wednesday Morning WSW 15-25
Wednesday Afternoon WSW 5-15
West North Ridgeline Winds (mph)
Tuesday Evening SW 15-25
Tuesday Night WSW 25-35
Wednesday Morning WSW 10-20
Wednesday Afternoon SW 5-15
West Central Ridgeline Winds (mph)
Tuesday Evening SW 15-25
Tuesday Night W 20-30
Wednesday Morning W 10-20
Wednesday Afternoon W 5-15
West South Ridgeline Winds (mph)
Tuesday Evening WSW 40-55
Tuesday Night W 30-40
Wednesday Morning W 25-35
Wednesday Afternoon W 15-25
Stevens Pass Ridgeline Winds (mph)
Tuesday Evening WSW 20-30
Tuesday Night W 25-35
Wednesday Morning W 15-25
Wednesday Afternoon W 10-20
Snoqualmie Pass Ridgeline Winds (mph)
Tuesday Evening W 40-55
Tuesday Night W 35-50
Wednesday Morning W 25-35
Wednesday Afternoon W 15-25
East North Ridgeline Winds (mph)
Tuesday Evening WSW 15-25
Tuesday Night WSW 25-35
Wednesday Morning W 20-30
Wednesday Afternoon W 10-20
East Central Ridgeline Winds (mph)
Tuesday Evening W 40-55
Tuesday Night W 40-55
Wednesday Morning W 35-50
Wednesday Afternoon W 15-25
East South Ridgeline Winds (mph)
Tuesday Evening W 45-65
Tuesday Night W 35-50
Wednesday Morning W 30-40
Wednesday Afternoon W 15-25
Mt. Hood Ridgeline Winds (mph)
Tuesday Evening W 55-75
Tuesday Night W 40-55
Wednesday Morning W 35-50
Wednesday Afternoon W 30-40

Issued: 2:01 PM PST Tuesday, December 27, 2022

Extended Weather Synopsis

Another low pressure system will quickly develop Thursday night and reach our region early Friday morning. This system will bring higher precipitation totals than Thursday's frontal system, but nothing like what we've experienced over the last few days. Snow levels won't be too low or too high, so some lower-elevation trailheads will see rain.  Saturday is up in the air as the pattern begins to change and systems weaken as they approach the area.  We may squeeze out a dry day or have some light showers. 

Extended Snow Level (ft)

Thursday Night* Friday * Friday Night Saturday
West North 3000' 3500' 3000' 3000'
Snoqualmie Pass 2500' 3500' 3000' 3500'
Mt. Hood 4500' 4500' 4000' 4500'
West North Elevation
Thursday Night* 3000'
Friday * 3500'
Friday Night 3000'
Saturday 3000'
Snoqualmie Pass Elevation
Thursday Night* 2500'
Friday * 3500'
Friday Night 3000'
Saturday 3500'
Mt. Hood Elevation
Thursday Night* 4500'
Friday * 4500'
Friday Night 4000'
Saturday 4500'

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

Previous forecast from Dec 27, 2022

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’.