Issued: 8:27 AM PST Thursday, December 25, 2014
by Dennis D'Amico

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

Weather Synopsis for Thursday & Monday

Merry Christmas and Happy Holidays from the Northwest Avalanche Center!  

Scattered showers should continue today for the mountains with some light snow accumulations expected. A convergence zone downwind of Vancouver Island will continue to focus a steady stream of light snow showers in the Stevens Pass vicinity. Expect winds near crest level to be moderate out of the NW... and even strong down near Mt. Hood. 

A developing system in the Gulf of Alaska will begin to flatten the upper level ridge positioned offshore. The system will approach from the NW Friday night... with increasing clouds and light precipitation spreading over the north and central Cascades and Olympics by early Saturday morning. 

Weather Forecast

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

Partly to mostly cloudy. Scattered snow showers. 

Thursday Night - Friday Morning

Partly cloudy with isolated snow showers. 

Friday Afternoon - Friday Evening

Increasing mid and high level clouds.  Isolated snow showers. 

East slopes of the Washington Cascades
Thursday

Partly cloudy. Isolated snow showers. 

Thursday Night - Friday Morning

Mostly clear. 

Friday Afternoon - Friday Evening

Partly cloudy, then increasing mid and high level clouds. 

Mt. Hood Area
Thursday

Partly to mostly cloudy. Scattered snow showers.  Strong upper mountain winds. 

Thursday Night - Friday

Partly cloudy with isolated snow showers. 

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Thursday - Thursday Night Snow Level 2500' 2000' 1500' ' ' 2000' ' 2500'
Hurricane Ridge Elevation
Thursday - Thursday Night Snow Level
2500'
Friday - Friday Night Snow Level
3500'
Mt. Baker Elevation
Thursday - Thursday Night Snow Level
2000'
Friday - Friday Night Snow Level
2500'
Washington Pass Elevation
Thursday - Thursday Night Snow Level
1500'
Friday - Friday Night Snow Level
2000'
Leavenworth Elevation
Thursday - Thursday Night Snow Level
'
Friday - Friday Night Snow Level
'
Stevens Pass Elevation
Thursday - Thursday Night Snow Level
'
Friday - Friday Night Snow Level
'
Snoqualmie Pass Elevation
Thursday - Thursday Night Snow Level
2000'
Friday - Friday Night Snow Level
3000'
Mt. Rainier & Crystal Elevation
Thursday - Thursday Night Snow Level
'
Friday - Friday Night Snow Level
'
Mt. Hood Elevation
Thursday - Thursday Night Snow Level
2500'
Friday - Friday Night Snow Level
3500'

* 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

Monday Monday
Hurricane Ridge LT 0.10 LT 0.25
Mt Baker Ski Area LT 0.10 LT 0.25
Washington Pass LT 0.10 LT 0.10
Stevens Pass LT 0.25 LT 0.25
Snoqualmie Pass LT 0.25 LT 0.25
Mission Ridge LT 0.10 LT 0.10
Crystal Mt LT 0.10 LT 0.10
Paradise LT 0.10 LT 0.10
White Pass LT 0.10 LT 0.10
Mt Hood Meadows LT 0.10 LT 0.10
LT 0.10 LT 0.10

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Thursday - Thursday Night NW 5 - 15 W 5 - 15 NW 5 - 15 --- - NW 10 - 20
Friday - Friday Evening W 5 - 15 SW 0 - 10 W 0 - 10 --- - W 5 - 15
Hurricane Ridge Elevation
Thursday - Thursday Night NW 5 - 15
Friday - Friday Evening W 5 - 15
Friday Night W 15 - 25
Mt. Baker Elevation
Thursday - Thursday Night W 5 - 15
Friday - Friday Evening SW 0 - 10
Friday Night SW 15 - 25
Stevens and Snoqualmie Pass Elevation
Thursday - Thursday Night NW 5 - 15
Friday - Friday Evening W 0 - 10
Friday Night W 10 - 20
Mt. Rainier Elevation
Thursday - Thursday Night --- -
Friday - Friday Evening --- -
Friday Night --- -
Mt. Hood Elevation
Thursday - Thursday Night NW 10 - 20
Friday - Friday Evening W 5 - 15
Friday Night W 10 - 20
Hurricane Ridge Direction - Speed
Thursday - Thursday Night NW 5 - 15
Friday - Friday Evening W 5 - 15
Friday Night W 15 - 25
Mt. Baker Direction - Speed
Thursday - Thursday Night W 5 - 15
Friday - Friday Evening SW 0 - 10
Friday Night SW 15 - 25
Stevens and Snoqualmie Pass Direction - Speed
Thursday - Thursday Night NW 5 - 15
Friday - Friday Evening W 0 - 10
Friday Night W 10 - 20
Mt. Rainier Direction - Speed
Thursday - Thursday Night --- -
Friday - Friday Evening --- -
Friday Night --- -
Mt. Hood Direction - Speed
Thursday - Thursday Night NW 10 - 20
Friday - Friday Evening W 5 - 15
Friday Night W 10 - 20

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
Thursday NW 10 - 20 NW 5 - 15 NW 20 - 30 --- - NW 35 - 50
Thursday Night NW 10 - 20 NW 5 - 15 NW 15 - 25 --- - NW 25 - 35
Friday - Friday Evening NW 15 - 25 W 5 - 15 NW 20 - 30 --- - NW 15 - 25
Mt. Baker Direction - Speed
Thursday NW 10 - 20
Thursday Night NW 10 - 20
Friday - Friday Evening NW 15 - 25
Friday Night W 20 - 30
Washington Pass Direction - Speed
Thursday NW 5 - 15
Thursday Night NW 5 - 15
Friday - Friday Evening W 5 - 15
Friday Night WNW 25 - 35
Stevens and Snoqualmie Pass Direction - Speed
Thursday NW 20 - 30
Thursday Night NW 15 - 25
Friday - Friday Evening NW 20 - 30
Friday Night NW 40 - 50
Mt. Rainier Direction - Speed
Thursday --- -
Thursday Night --- -
Friday - Friday Evening --- -
Friday Night --- -
Mt. Hood Direction - Speed
Thursday NW 35 - 50
Thursday Night NW 25 - 35
Friday - Friday Evening NW 15 - 25
Friday Night NW 30 - 40

Extended Weather Synopsis for Monday night through Monday

The closed upper low will pass over the central-north Cascades Saturday and quickly traverse toward the ID/WA border Saturday night. This upper low should deliver a healthy shot of snow to PNW mountains Saturday and Saturday night in favorable W-NW flow. Snow levels should stay on the cool side... but a mid-day bump to near or above 3000 feet for Snoqualmie Pass area is still possible.   

Strong arctic high pressure will begin to slide south out of northern British Columbia Sunday. The upper level flow should quickly turn northerly on Sunday... with some clearing and decreasing showers during the day.  Light upslope showers should develop for the north slopes of the Olympics and along the east slopes of the Cascades. 

Monday looks mostly clear and cold.  Strong offshore gradients will develop as the arctic high pressure slides further south... and consistently moderate to strong easterly winds are expected in the passes and at crest level Monday. 

Extended Weather

Olympics, Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes and Mt. Hood area
Saturday

Moderate rain and snow. Windy. 

Saturday Night

Light to moderate snow showers. 

Sunday

Decreasing scattered snow showers with partial clearing. 

Sunday Night - Monday

Mostly clear and cold. Increasing east winds Monday.  

East slopes of the Washington Cascades
Saturday

Light to occasionally moderate rain and snow. Windy. 

Saturday Night

Light snow showers. 

Sunday

Partly to mostly cloudy with scattered snow showers. 

Sunday Night - Monday

Mostly clear and cold. Increasing east winds Monday.  

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Saturday Morning - Saturday Mid-day Snow Level 2000' - 3000' 3000' - 4000' 3000' - 4000'
Saturday Afternoon - Evening Snow Level 2000' - 3000' 2500' - 3500' 3000' - 4000'
Saturday Night - Sunday Snow Level 1500' - 2500' 1500' - 2500' 2000' - 3000'
Mt. Baker Elevation
Saturday Morning - Saturday Mid-day Snow Level
2000' - 3000'
Saturday Afternoon - Evening Snow Level
2000' - 3000'
Saturday Night - Sunday Snow Level
1500' - 2500'
Sunday Night - Monday Freezing Level
0' - 500'
Snoqualmie Pass Elevation
Saturday Morning - Saturday Mid-day Snow Level
3000' - 4000'
Saturday Afternoon - Evening Snow Level
2500' - 3500'
Saturday Night - Sunday Snow Level
1500' - 2500'
Sunday Night - Monday Freezing Level
0' - 500'
Mt. Hood Elevation
Saturday Morning - Saturday Mid-day Snow Level
3000' - 4000'
Saturday Afternoon - Evening Snow Level
3000' - 4000'
Saturday Night - Sunday Snow Level
2000' - 3000'
Sunday Night - Monday Freezing Level
0' - 1000'

* 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.

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

Previous forecast from Dec 24, 2014

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.