Issued: 7:16 AM PST Monday, December 18, 2017
by Robert Hahn

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

Weather Synopsis for Monday & Saturday

On Monday, we will have strong westerly flow over the Pacific northwest with a strong N-S temperature gradient with an E-W oriented front lingering of the central and southern Cascades.

On Monday night, continued strong southwest flow lifts a front north to the Olympics and Washington Cascades.

Tuesday, a deepening surface low and front cross the Olympics in the late morning and the north Cascades early in the afternoon. Alpine winds will be strong and shifting over the course of the day.

Tuesday night, a deep, sharp upper trough swings across the Pafcific Northwest bringing decreasing and shifting winds with decreasing snow levels.

Weather Forecast

Olympics
Monday Decreasing light rain and snow in the morning; increasing light rain and snow in the afternoon.
Monday Night Increasing moderate to heavy rain and snow; shifting alpine winds.
Tuesday Increasing moderate to heavy rain and snow in the morning with light showers in the afternoon. Shifting alpine winds.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Monday Decreasing moderate to heavy rain and snow central part with light to moderate rain and snow north and south.
Monday Night Decreasing mostly light rain and snow, heaviest central and southern parts.
Tuesday Increasing moderate to heavy rain and snow. Strong , shifting alpine winds.
East Slopes of the Washington Cascades
Monday Decreasing light to moderate rain and snow, heaviest south and central parts.
Monday Night Decreasing light rain and snow, heaviest south and central parts.
Tuesday Increasing moderate rain and snow. Strong alpine winds shifting late in the day.
Mt. Hood
Monday Moderate rain and snow.
Monday Night Light, occasionally moderate rain and snow increasing an hour or two before sunrise. Strong alpine winds.
Tuesday Increasing moderate to heavy rain and snow especially in the afternoon. Strong to extreme alpine winds.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Monday Morning Snow Level 3500' 3000' 3500' ' ' 4000' ' 6000'
Monday Afternoon Snow Level 3000' 2500' 2500' ' ' 3000' ' 6000'
Monday Night Snow Level * 2000' 2000' 2000' ' ' 3000' ' 6000'
Tuesday Morning Snow Level * 3500' 2500' 2500' ' ' 4000' ' 5000'
Tuesday Afternoon Snow Level 1000' 2000' 3000' ' ' 2500' ' 3000'
Hurricane Ridge Elevation
Monday Morning Snow Level
3500'
Monday Afternoon Snow Level
3000'
Monday Night Snow Level
2000'
(Easterly Flow *)
Tuesday Morning Snow Level
3500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
1000'
Tuesday Night Snow Level
500'
Mt. Baker Elevation
Monday Morning Snow Level
3000'
Monday Afternoon Snow Level
2500'
Monday Night Snow Level
2000'
(Easterly Flow *)
Tuesday Morning Snow Level
2500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
2000'
Tuesday Night Snow Level
500'
Washington Pass Elevation
Monday Morning Snow Level
3500'
Monday Afternoon Snow Level
2500'
Monday Night Snow Level
2000'
(Easterly Flow *)
Tuesday Morning Snow Level
2500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
3000'
Tuesday Night Snow Level
500'
Leavenworth Elevation
Monday Morning Snow Level
'
Monday Afternoon Snow Level
'
Monday Night Snow Level
'
(Easterly Flow *)
Tuesday Morning Snow Level
'
(Easterly Flow *)
Tuesday Afternoon Snow Level
'
Tuesday Night Snow Level
'
Stevens Pass Elevation
Monday Morning Snow Level
'
Monday Afternoon Snow Level
'
Monday Night Snow Level
'
(Easterly Flow *)
Tuesday Morning Snow Level
'
(Easterly Flow *)
Tuesday Afternoon Snow Level
'
Tuesday Night Snow Level
'
Snoqualmie Pass Elevation
Monday Morning Snow Level
4000'
Monday Afternoon Snow Level
3000'
Monday Night Snow Level
3000'
(Easterly Flow *)
Tuesday Morning Snow Level
4000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
2500'
Tuesday Night Snow Level
1000'
Mt. Rainier & Crystal Elevation
Monday Morning Snow Level
'
Monday Afternoon Snow Level
'
Monday Night Snow Level
'
(Easterly Flow *)
Tuesday Morning Snow Level
'
(Easterly Flow *)
Tuesday Afternoon Snow Level
'
Tuesday Night Snow Level
'
Mt. Hood Elevation
Monday Morning Snow Level
6000'
Monday Afternoon Snow Level
6000'
Monday Night Snow Level
6000'
(Easterly Flow *)
Tuesday Morning Snow Level
5000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
3000'
Tuesday Night Snow Level
1500'

* 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

Saturday Saturday
Hurricane Ridge 0 - 1.00 0 - 1.00
Mt Baker Ski Area 0 - 0.75 2.00 - 2.50
Washington Pass 0 - 0.75 1.00 - 1.50
Stevens Pass 1.00 - 1.50 1.00 - 1.50
Snoqualmie Pass 1.50 - 2.00 1.00 - 1.50
Mission Ridge 0.25 - 0.50 0 - 0.50
Crystal Mt 0.75 - 1.00 1.00 - 1.50
Paradise 0 - 2.00 1.00 - 1.50
White Pass 0 - 1.00 0 - 1.00
Mt Hood Meadows 0.75 - 1.00 1.00 - 1.50
0 - 1.00 0 - 1.50

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Monday Morning WSW 10 - 20 WSW 10 - 20 WSW 20 - 30 --- - WSW 30 - 40
Monday Afternoon W 5 - 15 SW 5 - 15 W 10 - 20 --- - WSW 25 - 35
Monday Night SSE 10 - 20 SE 5 - 15 S 20 - 30 --- - SW 35 - 50
Tuesday Morning WSW 10 - 20 SSE 15 - 25 S 25 - 35 --- - SW 40 - 55
Tuesday Afternoon W 20 - 30 W 5 - 15 WSW 35 - 50 --- - W 30 - 45
Hurricane Ridge Elevation
Monday Morning WSW 10 - 20
Monday Afternoon W 5 - 15
Monday Night SSE 10 - 20
Tuesday Morning WSW 10 - 20
Tuesday Afternoon W 20 - 30
Tuesday Night N 5 - 15
Mt. Baker Elevation
Monday Morning WSW 10 - 20
Monday Afternoon SW 5 - 15
Monday Night SE 5 - 15
Tuesday Morning SSE 15 - 25
Tuesday Afternoon W 5 - 15
Tuesday Night N 5 - 15
Stevens and Snoqualmie Pass Elevation
Monday Morning WSW 20 - 30
Monday Afternoon W 10 - 20
Monday Night S 20 - 30
Tuesday Morning S 25 - 35
Tuesday Afternoon WSW 35 - 50
Tuesday Night W 15 - 25
Mt. Rainier Elevation
Monday Morning --- -
Monday Afternoon --- -
Monday Night --- -
Tuesday Morning --- -
Tuesday Afternoon --- -
Tuesday Night --- -
Mt. Hood Elevation
Monday Morning WSW 30 - 40
Monday Afternoon WSW 25 - 35
Monday Night SW 35 - 50
Tuesday Morning SW 40 - 55
Tuesday Afternoon W 30 - 45
Tuesday Night WSW 30 - 45
Hurricane Ridge Direction - Speed
Monday Morning WSW 10 - 20
Monday Afternoon W 5 - 15
Monday Night SSE 10 - 20
Tuesday Morning WSW 10 - 20
Tuesday Afternoon W 20 - 30
Tuesday Night N 5 - 15
Mt. Baker Direction - Speed
Monday Morning WSW 10 - 20
Monday Afternoon SW 5 - 15
Monday Night SE 5 - 15
Tuesday Morning SSE 15 - 25
Tuesday Afternoon W 5 - 15
Tuesday Night N 5 - 15
Stevens and Snoqualmie Pass Direction - Speed
Monday Morning WSW 20 - 30
Monday Afternoon W 10 - 20
Monday Night S 20 - 30
Tuesday Morning S 25 - 35
Tuesday Afternoon WSW 35 - 50
Tuesday Night W 15 - 25
Mt. Rainier Direction - Speed
Monday Morning --- -
Monday Afternoon --- -
Monday Night --- -
Tuesday Morning --- -
Tuesday Afternoon --- -
Tuesday Night --- -
Mt. Hood Direction - Speed
Monday Morning WSW 30 - 40
Monday Afternoon WSW 25 - 35
Monday Night SW 35 - 50
Tuesday Morning SW 40 - 55
Tuesday Afternoon W 30 - 45
Tuesday Night WSW 30 - 45

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
Monday Morning W 45 - 65 W 35 - 45 W 45 - 65 --- - W 40 - 60
Monday Afternoon WSW 40 - 60 WSW 25 - 35 WSW 45 - 65 --- - WSW 40 - 60
Monday Night SW 45 - 65 SSW 40 - 60 SW 50 - 70 --- - SW 50 - 80
Tuesday Morning SW 30 - 45 S 50 - 70 SW 60 - 80 --- - SW 65 - 85
Tuesday Afternoon W 25 - 35 WSW 15 - 25 WSW 45 - 65 --- - W 50 - 70
Mt. Baker Direction - Speed
Monday Morning W 45 - 65
Monday Afternoon WSW 40 - 60
Monday Night SW 45 - 65
Tuesday Morning SW 30 - 45
Tuesday Afternoon W 25 - 35
Tuesday Night W 10 - 20
Washington Pass Direction - Speed
Monday Morning W 35 - 45
Monday Afternoon WSW 25 - 35
Monday Night SSW 40 - 60
Tuesday Morning S 50 - 70
Tuesday Afternoon WSW 15 - 25
Tuesday Night NW 10 - 20
Stevens and Snoqualmie Pass Direction - Speed
Monday Morning W 45 - 65
Monday Afternoon WSW 45 - 65
Monday Night SW 50 - 70
Tuesday Morning SW 60 - 80
Tuesday Afternoon WSW 45 - 65
Tuesday Night W 35 - 45
Mt. Rainier Direction - Speed
Monday Morning --- -
Monday Afternoon --- -
Monday Night --- -
Tuesday Morning --- -
Tuesday Afternoon --- -
Tuesday Night --- -
Mt. Hood Direction - Speed
Monday Morning W 40 - 60
Monday Afternoon WSW 40 - 60
Monday Night SW 50 - 80
Tuesday Morning SW 65 - 85
Tuesday Afternoon W 50 - 70
Tuesday Night W 40 - 60

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 Dec 17, 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.