Issued: 7:24 AM PST Friday, December 1, 2017
by Dennis D'Amico

Jump to: Weather Forecast I Snow/Freezing Level I Precipitation I Free Winds 5k I Free Winds 9k

Weather Synopsis for Friday & Wednesday

A frontal system emanating from a broad upper level trough in the Gulf of Alaska will hang up over the Olympics and north Cascades today before weakening as it slides further south tonight.  This should result in light to moderate snow for the Olympics and north Cascades and not much in the way of precipitation for areas further south during the daylight hours. An increase in SW winds out ahead of the front and a gradual lowering of cloud bases for the south and central Washington Cascades should occur as well. 

Showers should taper down Friday night but the upper level trough will dig off the PNW coast later tonight into Saturday. A weak surface low should develop on Saturday off the WA/OR coast and begin to enhance showers in the afternoon.  This pattern favors orographic enhancement for the SW Cascades (Paradise, Crystal, White Pass) and along with the east slopes of the Cascades, while the northwest Cascades should begin to dry out with partial clearing in the afternoon. 

As local N-NE winds increase Saturday afternoon and night for the Olympics, a period of upslope snow showers for the north slopes of the Olympics may produce locally moderate amounts of snow. Mt. Hood will finally have some new snow to enjoy as snowfall increases Saturday afternoon through Saturday night. 

Weather Forecast

Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
Friday

Light to moderate rain and snow north Cascades.  Partly to mostly cloudy south and central Cascades with increasing clouds today. Light rain and snow developing central Cascades in the afternoon. 

Friday Night

Light rain and snow showers becoming scattered overnight. 

Saturday

Light rain and snow showers becoming locally moderate south and central Cascades. Partial clearing possible north Cascades in the afternoon. 

East slopes of the Washington Cascades
Friday

Light to occasionally moderate rain and snow developing northeast Cascades.  Partly to mostly cloudy southeast and central-east Cascades with increasing clouds today. Light rain and snow developing central-east Cascades late in the afternoon. 

Friday Night

Mostly cloudy with scattered rain and snow showers. 

Saturday

Cloudy with light rain and snow showers becoming locally moderate southeast and central-east Cascades.  

Olympics
Friday

Light to moderate rain and snow.  

Friday Night

Cloudy light rain and snow showers becoming mostly cloudy and scattered overnight. 

Saturday

Mostly cloudy with light rain and snow showers. 

Mt. Hood Area
Friday

Partly to mostly cloudy. 

Friday Night

Cloudy with periods of light rain and snow. 

Saturday

Light rain and snow showers becoming occasionally moderate in the late afternoon. 

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Friday Morning Snow Level 3500' 2500' 2500' ' ' 2500' ' 3500'
Friday Afternoon Snow Level 3500' 2500' 2500' ' ' 3500' ' 4500'
Friday Night Snow Level 2500' 2500' 2000' ' ' 3000' ' 4000'
Saturday Morning Snow Level 2500' 2000' 2000' ' ' 2500' ' 3500'
Saturday Afternoon Snow Level 2500' 2500' 2500' ' ' 3000' ' 3500'
Hurricane Ridge Elevation
Friday Morning Snow Level
3500'
Friday Afternoon Snow Level
3500'
Friday Night Snow Level
2500'
Saturday Morning Snow Level
2500'
Saturday Afternoon Snow Level
2500'
Saturday Night Snow Level
2000'
Mt. Baker Elevation
Friday Morning Snow Level
2500'
Friday Afternoon Snow Level
2500'
Friday Night Snow Level
2500'
Saturday Morning Snow Level
2000'
Saturday Afternoon Snow Level
2500'
Saturday Night Snow Level
1500'
Washington Pass Elevation
Friday Morning Snow Level
2500'
Friday Afternoon Snow Level
2500'
Friday Night Snow Level
2000'
Saturday Morning Snow Level
2000'
Saturday Afternoon Snow Level
2500'
Saturday Night Snow Level
1000'
Leavenworth Elevation
Friday Morning Snow Level
'
Friday Afternoon Snow Level
'
Friday Night Snow Level
'
Saturday Morning Snow Level
'
Saturday Afternoon Snow Level
'
Saturday Night Snow Level
'
Stevens Pass Elevation
Friday Morning Snow Level
'
Friday Afternoon Snow Level
'
Friday Night Snow Level
'
Saturday Morning Snow Level
'
Saturday Afternoon Snow Level
'
Saturday Night Snow Level
'
Snoqualmie Pass Elevation
Friday Morning Snow Level
2500'
Friday Afternoon Snow Level
3500'
Friday Night Snow Level
3000'
Saturday Morning Snow Level
2500'
Saturday Afternoon Snow Level
3000'
Saturday Night Snow Level
2500'
Mt. Rainier & Crystal Elevation
Friday Morning Snow Level
'
Friday Afternoon Snow Level
'
Friday Night Snow Level
'
Saturday Morning Snow Level
'
Saturday Afternoon Snow Level
'
Saturday Night Snow Level
'
Mt. Hood Elevation
Friday Morning Snow Level
3500'
Friday Afternoon Snow Level
4500'
Friday Night Snow Level
4000'
Saturday Morning Snow Level
3500'
Saturday Afternoon Snow Level
3500'
Saturday Night Snow Level
2500'

* Easterly flow in the Cascade Passes can cause locally lower Snow or Freezing levels than areas further west.
Freezing Level is when no precipitation is forecast.

Precipitation Forecast

Wednesday Wednesday
Hurricane Ridge 0 - 0.75 0.50 - 1.00
Mt Baker Ski Area 0 - 1.00 LT 0.25
Washington Pass 0 - 0.50 0.25 - 0.50
Stevens Pass 0 - 0.50 0.50 - 0.75
Snoqualmie Pass 0.50 - 0.75 0 - 0.50
Mission Ridge LT 0.10 0.25 - 0.50
Crystal Mt LT 0.25 0 - 0.50
Paradise 0 - 0.50 0 - 1.00
White Pass LT 0.25 0 - 0.50
Mt Hood Meadows LT 0.10 0.75 - 1.00
LT 0.10 0 - 1.00

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Friday Morning SW 15 - 25 S 15 - 25 SW 10 - 20 --- - SW 5 - 15
Friday Afternoon SW 15 - 25 S 10 - 20 SW 15 - 30 --- - SW 10 - 20
Friday Night SW 10 - 20 SSW 5 - 15 SW 15 - 30 --- - SW 15 - 25
Saturday Morning SW 5 - 15 SSW 5 - 15 SW 10 - 20 --- - SW 10 - 20
Saturday Afternoon ENE 5 - 15 NE 0 - 10 ESE 0 - 10 --- - SSW 10 - 20
Hurricane Ridge Elevation
Friday Morning SW 15 - 25
Friday Afternoon SW 15 - 25
Friday Night SW 10 - 20
Saturday Morning SW 5 - 15
Saturday Afternoon ENE 5 - 15
Saturday Night N 5 - 15
Mt. Baker Elevation
Friday Morning S 15 - 25
Friday Afternoon S 10 - 20
Friday Night SSW 5 - 15
Saturday Morning SSW 5 - 15
Saturday Afternoon NE 0 - 10
Saturday Night N 0 - 10
Stevens and Snoqualmie Pass Elevation
Friday Morning SW 10 - 20
Friday Afternoon SW 15 - 30
Friday Night SW 15 - 30
Saturday Morning SW 10 - 20
Saturday Afternoon ESE 0 - 10
Saturday Night NW 0 - 10
Mt. Rainier Elevation
Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Saturday Morning --- -
Saturday Afternoon --- -
Saturday Night --- -
Mt. Hood Elevation
Friday Morning SW 5 - 15
Friday Afternoon SW 10 - 20
Friday Night SW 15 - 25
Saturday Morning SW 10 - 20
Saturday Afternoon SSW 10 - 20
Saturday Night WSW 15 - 25
Hurricane Ridge Direction - Speed
Friday Morning SW 15 - 25
Friday Afternoon SW 15 - 25
Friday Night SW 10 - 20
Saturday Morning SW 5 - 15
Saturday Afternoon ENE 5 - 15
Saturday Night N 5 - 15
Mt. Baker Direction - Speed
Friday Morning S 15 - 25
Friday Afternoon S 10 - 20
Friday Night SSW 5 - 15
Saturday Morning SSW 5 - 15
Saturday Afternoon NE 0 - 10
Saturday Night N 0 - 10
Stevens and Snoqualmie Pass Direction - Speed
Friday Morning SW 10 - 20
Friday Afternoon SW 15 - 30
Friday Night SW 15 - 30
Saturday Morning SW 10 - 20
Saturday Afternoon ESE 0 - 10
Saturday Night NW 0 - 10
Mt. Rainier Direction - Speed
Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Saturday Morning --- -
Saturday Afternoon --- -
Saturday Night --- -
Mt. Hood Direction - Speed
Friday Morning SW 5 - 15
Friday Afternoon SW 10 - 20
Friday Night SW 15 - 25
Saturday Morning SW 10 - 20
Saturday Afternoon SSW 10 - 20
Saturday Night WSW 15 - 25

Directions above indicate the direction the wind blows from on the 16-point cardinal scale. These winds indicate "free" winds, or those winds in the atmosphere not influenced by terrain. Topographical effects may produce greater or lower wind speeds in certain locations as well as significant variations in direction.

Free Winds at 9000' (mph)

Mt. Baker Washington Pass Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Friday Morning SW 25 - 35 WSW 25 - 35 WSW 25 - 35 --- - W 20 - 30
Friday Afternoon SW 20 - 30 SW 20 - 30 SW 35 - 45 --- - SW 25 - 35
Friday Night SW 15 - 25 SW 25 - 35 SW 30 - 40 --- - SW 25 - 35
Saturday Morning SW 15 - 25 SW 20 - 30 SW 25 - 35 --- - SW 20 - 30
Saturday Afternoon SE 5 - 15 SE 0 - 10 S 10 - 20 --- - SW 20 - 30
Mt. Baker Direction - Speed
Friday Morning SW 25 - 35
Friday Afternoon SW 20 - 30
Friday Night SW 15 - 25
Saturday Morning SW 15 - 25
Saturday Afternoon SE 5 - 15
Saturday Night NE 5 - 15
Washington Pass Direction - Speed
Friday Morning WSW 25 - 35
Friday Afternoon SW 20 - 30
Friday Night SW 25 - 35
Saturday Morning SW 20 - 30
Saturday Afternoon SE 0 - 10
Saturday Night VAR 0 - 10
Stevens and Snoqualmie Pass Direction - Speed
Friday Morning WSW 25 - 35
Friday Afternoon SW 35 - 45
Friday Night SW 30 - 40
Saturday Morning SW 25 - 35
Saturday Afternoon S 10 - 20
Saturday Night W 10 - 20
Mt. Rainier Direction - Speed
Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Saturday Morning --- -
Saturday Afternoon --- -
Saturday Night --- -
Mt. Hood Direction - Speed
Friday Morning W 20 - 30
Friday Afternoon SW 25 - 35
Friday Night SW 25 - 35
Saturday Morning SW 20 - 30
Saturday Afternoon SW 20 - 30
Saturday Night W 25 - 35

Directions above indicate the direction the wind blows from on the 16-point cardinal scale. These winds indicate "free" winds, or those winds in the atmosphere not influenced by terrain. Topographical effects may produce greater or lower wind speeds in certain locations as well as significant variations in direction.

Jump to: Weather Forecast I Snow/Freezing Level I Precipitation I Free Winds 5k I Free Winds 9k

Previous forecast from Nov 30, 2017

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.