Issued: 7:15 AM PST Saturday, December 19, 2020
by Robert Hahn

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

Weather Synopsis

Saturday morning features a relative break from the very active weather and milder weather which will move in late Saturday. Light post-frontal very light rain and snow showers should linger Saturday morning with some relatively cooler air over the region on Saturday. Warm frontal precipitation moves into the region in the afternoon with increasing light to moderate rain and snow arriving in Washington State. While a warming trend begins, E flow out the outset of the system is likely to keep the passes as snow until 4-6 PM this evening. Precipitation intensifies in the evening as the cold front approaches, winds increase into the strong range and temperatures warm well above pass level across the region (4500 ft in the North; 6000 ft in the central Cascades; and 8000 ft in the Mt Hood region).

Expect 1-3.5" of water equivalent overnight with the cold decreasing moisture from north to south and focusing it on the Paradise and Mt Hood area. Some models maintain significant convergence in the post-frontal around the Stevens Pass area late Saturday night into early Sunday morning.

Sunday should be somewhat drier with light rain and snow showers, mild, but slightly cooler temperatures and heavier precipitation lingering with the front draped over Oregon. Mt. Hood could pick up another inch or so of water equivalent on Sunday.

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
Saturday Cloudy with light rain and snow developing and increasing in the afternoon. Warming trend late in the day.
Saturday Night Moderate rain and high elevation snow becoming light showers after midnight. Mild. Strong wind gusts.
Saturday Periods of light rain and snow in the morning, then moderate rain and snow in the afternoon. Cooler.
Saturday Night Heavy rain and snow. Warming trend. Strong winds.
Saturday Periods of light rain and snow in the morning, then increasing light to moderate rain and snow in the afternoon. Cooler.
Saturday Night Heavy rain and high elevation snow. Warming trend. Strong winds in the evening.
Saturday Mostly cloudy with very light rain and snow in the morning, then light rain and snow increasing in the afternoon.
Saturday Night Heavy rain and high elevation snow. Strong winds.
Saturday Periods of light rain and snow in the morning, then increasing light rain and snow in the afternoon. Cooler. Light W pass-level winds switching E late in the day.
Saturday Night Heavy rain and high elevation snow. Rapid warming trend in the evening. Strong ridgeline winds in the evening. Light to moderate E winds at pass level switching W in the evening.
Saturday Periods of light rain and snow in the morning, then increasing light rain and snow in the afternoon. Cooler. Light W pass-level winds switching E late in the day, with E flow likely to keep precipitation frozen.
Saturday Night Heavy rain and high elevation snow. Rapid warming trend in the evening. Strong ridgeline winds in the evening. Light to moderate E winds at pass level switching W in the evening.
Saturday Periods of light rain and snow increasing late in the day.
Saturday Night Heavy rain and snow. Warming trend.
Saturday Periods of light rain and snow increasing late in the day.
Saturday Night Heavy rain and high elevation snow. Warming trend.
Saturday Periods of light rain and snow increasing late in the day.
Saturday Night Heavy rain and high elevation snow. Warming trend.
Saturday Periods of light rain and snow increasing late in the day.
Saturday Night Heavy rain and high elevation snow. Warming trend. Strong winds.

Precipitation (in)

Saturday Saturday Night Sunday
4 am - 4 pm 4 pm - 4 am 4 am - 4 pm
Hurricane Ridge 0.25 0.50 - 0.75 0
Mt Baker Ski Area 0.50 1.00 - 1.50 LT 0.25
Mt. Loop - Barlow Pass 0.25 1.50 0.25
Stevens Pass LT 0.25 1.00 0.25
Snoqualmie Pass LT 0.25 1.00 - 1.50 LT 0.25
Crystal Mt LT 0.25 0.75 -1.00 LT 0.10
Paradise 0.25 2.50 LT 0.25
White Pass 0.25 1.50 - 2.00 LT 0.25
Washington Pass LT 0.25 1.00 LT 0.10
Mission Ridge LT 0.10 0.75 LT 0.10
Salmon la Sac - Gallagher Head LT 0.25 1.00 LT 0.25
Tieton River - Darland Mt. LT 0.25 1.00 - 1.50 0.25
Mt Hood Meadows LT 0.25 3.00 - 4.00 1.00
Timberline LT 0.25 3.00 - 4.00 1.00 - 1.50
Hurricane Ridge Precipitation (in)
Saturday 0.25
Saturday Night 0.50 - 0.75
Sunday 0
Mt Baker Ski Area Precipitation (in)
Saturday 0.50
Saturday Night 1.00 - 1.50
Sunday LT 0.25
Mt. Loop - Barlow Pass Precipitation (in)
Saturday 0.25
Saturday Night 1.50
Sunday 0.25
Stevens Pass Precipitation (in)
Saturday LT 0.25
Saturday Night 1.00
Sunday 0.25
Snoqualmie Pass Precipitation (in)
Saturday LT 0.25
Saturday Night 1.00 - 1.50
Sunday LT 0.25
Crystal Mt Precipitation (in)
Saturday LT 0.25
Saturday Night 0.75 -1.00
Sunday LT 0.10
Paradise Precipitation (in)
Saturday 0.25
Saturday Night 2.50
Sunday LT 0.25
White Pass Precipitation (in)
Saturday 0.25
Saturday Night 1.50 - 2.00
Sunday LT 0.25
Washington Pass Precipitation (in)
Saturday LT 0.25
Saturday Night 1.00
Sunday LT 0.10
Mission Ridge Precipitation (in)
Saturday LT 0.10
Saturday Night 0.75
Sunday LT 0.10
Salmon la Sac - Gallagher Head Precipitation (in)
Saturday LT 0.25
Saturday Night 1.00
Sunday LT 0.25
Tieton River - Darland Mt. Precipitation (in)
Saturday LT 0.25
Saturday Night 1.00 - 1.50
Sunday 0.25
Mt Hood Meadows Precipitation (in)
Saturday LT 0.25
Saturday Night 3.00 - 4.00
Sunday 1.00
Timberline Precipitation (in)
Saturday LT 0.25
Saturday Night 3.00 - 4.00
Sunday 1.00 - 1.50

Snow Level (ft)

Saturday Morning Saturday Afternoon Saturday Evening Saturday Night Sunday Morning Sunday Afternoon
Olympics 3500' 4000' 5500' 5500' 5500' 4000'
West North 2500' 2500' 3500' 4500' 4500' 3500'
West Central 3000' 3000' 4000' 5500' 5500' 4500'
West South 3000' 3500' 4500' 6500' 6500' 5000'
Stevens Pass 3000' 3000' 4000' 5500' 5500' 4500'
Snoqualmie Pass 3000' 3000' 4500' 6000' 6000' 4500'
East North 2500' 3000' 3500' 4500' 4500' 4000'
East Central 3000' 3000' 4000' 5500' 5500' 5000'
East South 4000' 4000' 5000' 6500' 6500' 5500'
Mt. Hood 5000' 5000' 6000' 8000' 8000' 7000'
Olympics Elevation
Saturday Morning 3500'
Saturday Afternoon 4000'
Saturday Evening 5500'
Saturday Night 5500'
Sunday Morning 5500'
Sunday Afternoon 4000'
West North Elevation
Saturday Morning 2500'
Saturday Afternoon 2500'
Saturday Evening 3500'
Saturday Night 4500'
Sunday Morning 4500'
Sunday Afternoon 3500'
West Central Elevation
Saturday Morning 3000'
Saturday Afternoon 3000'
Saturday Evening 4000'
Saturday Night 5500'
Sunday Morning 5500'
Sunday Afternoon 4500'
West South Elevation
Saturday Morning 3000'
Saturday Afternoon 3500'
Saturday Evening 4500'
Saturday Night 6500'
Sunday Morning 6500'
Sunday Afternoon 5000'
Stevens Pass Elevation
Saturday Morning 3000'
Saturday Afternoon 3000'
Saturday Evening 4000'
Saturday Night 5500'
Sunday Morning 5500'
Sunday Afternoon 4500'
Snoqualmie Pass Elevation
Saturday Morning 3000'
Saturday Afternoon 3000'
Saturday Evening 4500'
Saturday Night 6000'
Sunday Morning 6000'
Sunday Afternoon 4500'
East North Elevation
Saturday Morning 2500'
Saturday Afternoon 3000'
Saturday Evening 3500'
Saturday Night 4500'
Sunday Morning 4500'
Sunday Afternoon 4000'
East Central Elevation
Saturday Morning 3000'
Saturday Afternoon 3000'
Saturday Evening 4000'
Saturday Night 5500'
Sunday Morning 5500'
Sunday Afternoon 5000'
East South Elevation
Saturday Morning 4000'
Saturday Afternoon 4000'
Saturday Evening 5000'
Saturday Night 6500'
Sunday Morning 6500'
Sunday Afternoon 5500'
Mt. Hood Elevation
Saturday Morning 5000'
Saturday Afternoon 5000'
Saturday Evening 6000'
Saturday Night 8000'
Sunday Morning 8000'
Sunday Afternoon 7000'

5000' Temperatures (°F)

Saturday Saturday Night
Max / Min Max / Min
Olympics 31 / 24 37 / 28
West North 28 / 24 34 / 28
West Central 28 / 25 35 / 29
West South 32 / 27 36 / 32
Stevens Pass 30 / 26 36 / 30
Snoqualmie Pass 30 / 26 35 / 29
East North 28 / 24 35 / 27
East Central 30 / 25 35 / 29
East South 33 / 26 35 / 30
Mt. Hood 33 / 32 37 / 32
Olympics 5000' Temperature Forecast
(Max / Min)
Saturday 31 / 24
Saturday Night 37 / 28
West North 5000' Temperature Forecast
(Max / Min)
Saturday 28 / 24
Saturday Night 34 / 28
West Central 5000' Temperature Forecast
(Max / Min)
Saturday 28 / 25
Saturday Night 35 / 29
West South 5000' Temperature Forecast
(Max / Min)
Saturday 32 / 27
Saturday Night 36 / 32
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Saturday 30 / 26
Saturday Night 36 / 30
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Saturday 30 / 26
Saturday Night 35 / 29
East North 5000' Temperature Forecast
(Max / Min)
Saturday 28 / 24
Saturday Night 35 / 27
East Central 5000' Temperature Forecast
(Max / Min)
Saturday 30 / 25
Saturday Night 35 / 29
East South 5000' Temperature Forecast
(Max / Min)
Saturday 33 / 26
Saturday Night 35 / 30
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Saturday 33 / 32
Saturday Night 37 / 32

Ridgeline Winds (mph)

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

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

Previous forecast from Dec 18, 2020

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’.