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Mountain Weather Forecast

Issued: 1:28 PM Thursday, March 5, 2015
by Kenny Kramer

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.

Weather synopsis for Thursday & Friday

No significant changes to the afternoon update, status quo.

The persistent upper ridge remains centered offshore along 130W with a frontal system riding over the ridge across central B.C. and spilling high level clouds across mainly the Olympics and north WA Cascades Thursday afternoon. Some thin high clouds are reaching the remainder of the WA Cascades and Mt Hood area Thursday afternoon. This will be the main theme over the next day until the ridge gains strength later Friday and skies again clear. 

Freezing levels are moderately high and will rise later Friday to the 9-10,000 ft range. Surface pressure gradients should remain relatively flat Thursday and Friday with pass level winds either light easterly overnight and morning hours shifting to light westerly in the afternoons. Winds at crest levels should remain mostly light as well.

Weather forecast for Thursday & Friday

Olympics
Date Weather
Thursday Afternoon - Friday Mid-day

Mostly cloudy with mainly high level clouds.

Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
Date Weather
Thursday Afternoon - Friday Mid-day

Partly to mostly cloudy with mainly high level clouds, especially north part.

East slopes of the Washington Cascades
Date Weather
Thursday Afternoon - Friday Mid-day

Partly to mostly cloudy with mainly high level clouds, especially north part.

Mt. Hood Area
Date Weather
Thursday Afternoon - Friday Night

Partly cloudy with filtered sun and high clouds Thursday afternoon and evening.

High clouds Thursday night. 

Mostly sunny on Friday and clear Friday night.

Snow Level/Freezing Level in feet

Date Olympics Northwest Cascades Northeast Cascades Central Cascades South Cascades Easterly Flow in Passes
Thursday Afternoon Freezing Level 7500' 6500' 6000' 7000' 9000'
Thursday Night Freezing Level 7500' 7000' 8000' 7500' 9500' *
Olympics
Date Elevation
Thursday Afternoon Freezing Level
7500'
Thursday Night Freezing Level
7500'
Easterly Flow*
Friday - Friday Night Freezing Level
8500'
Northwest Cascades
Date Elevation
Thursday Afternoon Freezing Level
6500'
Thursday Night Freezing Level
7000'
Easterly Flow*
Friday - Friday Night Freezing Level
8000'
Northeast Cascades
Date Elevation
Thursday Afternoon Freezing Level
6000'
Thursday Night Freezing Level
8000'
Easterly Flow*
Friday - Friday Night Freezing Level
9000'
Central Cascades
Date Elevation
Thursday Afternoon Freezing Level
7000'
Thursday Night Freezing Level
7500'
Easterly Flow*
Friday - Friday Night Freezing Level
9500'
South Cascades
Date Elevation
Thursday Afternoon Freezing Level
9000'
Thursday Night Freezing Level
9500'
Easterly Flow*
Friday - Friday Night Freezing Level
10000'

Cascade Snow / Freezing Levels noted above refer to the north (approximately Mt Baker and Washington Pass), central (approximately Stevens to White Pass) and south (near Mt Hood). Freezing Level is when no precipitation is forecast.
* Note that surface snow levels are common near the passes during easterly pass flow and may result in multiple snow / freezing levels.

24 Hour Quantitative Precipitation ending at 4 am

Location Fri Sat
Hurricane Ridge 0 0
Mt Baker Ski Area 0 0
Washington Pass 0 0
Stevens Pass 0 0
Snoqualmie Pass 0 0
Mission Ridge 0 0
Crystal Mt 0 0
Paradise 0 0
White Pass 0 0
Mt Hood Meadows 0 0

Winds in Miles per Hour (MPH) "Cascade Pass Level Winds"

Date Direction - Speed
Thursday Afternoon W 5 - 15
Thursday Night - Friday Morning VAR 0 - 10

Directions above indicate the direction the wind blows from on the 16-point cardinal scale. Winds near the passes tend to be highly channeled by the topography and normally blow either easterly or westerly depending on the surface pressure gradients that drive such winds.

Free Winds at 5000' (in Miles per Hour (MPH))

Date Olympics Northwest Cascades Central Cascades South Cascades
Olympics
Date Elevation
Thursday Afternoon - Friday Night W 0 - 10
Northwest Cascades
Date Elevation
Thursday Afternoon - Friday Night W 0 - 10
Central Cascades
Date Elevation
Thursday Afternoon - Friday Night W 0 - 10
South Cascades
Date Elevation
Thursday Afternoon - Friday Night W 0 - 10
Olympics
Date Direction - Speed
Thursday Afternoon - Friday Night W 0 - 10
Northwest Cascades
Date Direction - Speed
Thursday Afternoon - Friday Night W 0 - 10
Central Cascades
Date Direction - Speed
Thursday Afternoon - Friday Night W 0 - 10
South Cascades
Date Direction - Speed
Thursday Afternoon - Friday Night W 0 - 10

Directions above indicate the direction the wind blows from on the 16-point cardinal scale. These winds and the 9000 ft winds below also 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' (in Miles per Hour (MPH))

Date Northwest Cascades Northeast Cascades Central Cascades South Cascades
Thursday Afternoon WNW 15 - 25 WNW 10 - 20 WNW 10 - 20 WNW 10 - 20
Thursday Night - Friday Morning NW 20 - 30 NW 20 - 30 NW 10 - 20 NW 5 - 15
Northwest Cascades
Date Direction - Speed
Thursday Afternoon WNW 15 - 25
Thursday Night - Friday Morning NW 20 - 30
Friday Afternoon - Friday Night W 10 - 20
Northeast Cascades
Date Direction - Speed
Thursday Afternoon WNW 10 - 20
Thursday Night - Friday Morning NW 20 - 30
Friday Afternoon - Friday Night WNW 10 - 20
Central Cascades
Date Direction - Speed
Thursday Afternoon WNW 10 - 20
Thursday Night - Friday Morning NW 10 - 20
Friday Afternoon - Friday Night W 5 - 15
South Cascades
Date Direction - Speed
Thursday Afternoon WNW 10 - 20
Thursday Night - Friday Morning NW 5 - 15
Friday Afternoon - Friday Night W 5 - 15

Extended Weather Synopsis for Saturday through Monday

The upper ridge should dominate the weather pattern over the PNW through the weekend, maintaining clear skies and high freezing levels with light winds.

A weak frontal system may begin to spread high clouds across the area Monday with a little light precipitation reaching the area Monday night, however amounts, if any, are expected to be light.

Extended Weather Forecast for Saturday through Monday

Olympics, Washington Cascades, Mt Hood
Date Weather
Saturday - Sunday

Mostly fair with a few high clouds, mainly Olympics and north Washington Cascades. Mostly fair central WA Cascdes to Mt Hood.

Monday

Increasing mid and high clouds.

Snow/Freezing Levels

Date Olympics Northwest Cascades Northeast Cascades Central Cascades South Cascades Easterly Flow in Passes
Saturday - Sunday Night Freezing Level 9000' - 10000' 7500' - 9000' 7500' - 9000' 9000' - 10000' 10000' - 11000'
Monday Freezing Level 7500' - 8500' 6500' - 7500' 8000' - 9000' 8500' - 9500' 9000' - 10000'
Olympics
Date Elevation
Saturday - Sunday Night Freezing Level
9000' - 10000'
Monday Freezing Level
7500' - 8500'
Monday Night Snow Level
5500' - 6500'
Northwest Cascades
Date Elevation
Saturday - Sunday Night Freezing Level
7500' - 9000'
Monday Freezing Level
6500' - 7500'
Monday Night Snow Level
5000' - 6000'
Northeast Cascades
Date Elevation
Saturday - Sunday Night Freezing Level
7500' - 9000'
Monday Freezing Level
8000' - 9000'
Monday Night Snow Level
5000' - 6000'
Central Cascades
Date Elevation
Saturday - Sunday Night Freezing Level
9000' - 10000'
Monday Freezing Level
8500' - 9500'
Monday Night Snow Level
6000' - 7000'
South Cascades
Date Elevation
Saturday - Sunday Night Freezing Level
10000' - 11000'
Monday Freezing Level
9000' - 10000'
Monday Night Snow Level
7000' - 8000'

Freezing Level is when no precipitation is forecast.
* Note that surface snow levels are common near the passes during easterly pass flow and may result in multiple snow / freezing levels.