Issued: 7:54 AM PDT Thursday, April 13, 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 Thursday & Tuesday

A vertically stacked low pressure system off the Washington/British Columbia border will continue the unsettled weather pattern for the Pacific Northwest over the short term. An upper level shortwave lifted north over the area Wednesday night, resulting in modest amounts of precipitation and new snow above 4000 feet along both the east slopes and west slopes of the Cascades. A band of showers along the Washington/Oregon border this morning should mainly affect the Olympics and peter out as they push into the Cascades. With a cool unstable air mass overhead, look for increasing shower activity this afternoon over the Cascades. The air mass is marginally unstable such that an isolated thunderstorm can't be ruled out this afternoon. Shower activity should wane overnight with the loss of day-time heating. 

The story on Friday will be similar with the same low pressure system meandering north and west and further away from Vancouver Island. The air mass will be slightly cooler on Friday. An upper level shortwave swinging through in the late afternoon/early evening should cause for a period of more moderate showers especially for the west slopes of the Cascades including Mt. Hood.  A Puget Sound Convergence zone may form during this period causing locally higher accumulations in the Mountain Loop Region. Shower activity should once again ease Friday night. 

Weather Forecast

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

Cloudy northwest Cascades with light to occasionally moderate rain and showers. Mostly cloudy with scattered light rain and snow showers central-west and southwest Cascades. 

Thursday Afternoon - Thursday Evening

Mostly cloudy with light to occasionally moderate rain and snow showers. Afternoon sunbreaks possible. Slight chance of a thunderstorm. 

Thursday Night - Friday Morning

Mostly cloudy with scattered light rain and snow showers. 

Friday Afternoon - Friday Evening

Mostly cloudy with light rain to occasionally moderate rain and snow showers. Afternoon sunbreaks possible. Slight chance of a thunderstorm in the afternoon and evening. Locally heavier accumulations possible near a convergence zone Mountain Loop area. 

Olympics
Thursday Morning

Mostly cloudy with scattered light to occasionally moderate rain and snow showers. 

Thursday Afternoon - Thursday Evening

Mostly cloudy with light to occasionally moderate rain and snow showers. Afternoon sunbreaks possible. Slight chance of a thunderstorm. 

Thursday Night - Friday Morning

Mostly cloudy with scattered light rain and snow showers. 

Friday Afternoon - Friday Evening

Mostly cloudy with light rain to occasionally moderate rain and snow showers. Afternoon sunbreaks possible. Slight chance of a thunderstorm. 

East slopes of the Washington Cascades
Thursday Morning

Cloudy northeast Cascades with light to occasionally moderate rain and showers. Partly to mostly cloudy with scattered light rain and snow showers central-west and southwest Cascades. 

Thursday Mid-day - Thursday Evening

Mostly cloudy with light to occasionally moderate rain and snow showers, heaviest near the Cascade crest. Afternoon sunbreaks possible. Slight chance of a thunderstorm. 

Thursday Night - Friday Morning

Partly cloudy with isolated light rain and snow showers. 

Friday Afternoon - Friday Evening

Mostly cloudy with light rain to occasionally moderate rain and snow showers especially near the Cascade crest. Afternoon sunbreaks possible. Slight chance of a thunderstorm. 

Mt. Hood Area
Thursday Morning

Mostly cloudy with scattered light rain and snow showers. 

Thursday Afternoon - Thursday Evening

Mostly cloudy with light to occasionally moderate rain and snow showers. Afternoon sunbreaks possible. Slight chance of a thunderstorm. 

Thursday Night - Friday Morning

Mostly cloudy with scattered light rain and snow showers. 

Friday Afternoon - Friday Evening

Mostly cloudy with light rain to occasionally moderate rain and snow showers. Afternoon sunbreaks possible. Slight chance of a thunderstorm. 

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Thursday Morning Snow Level 3000' 3000' 3500' ' ' 3000' ' 3000'
Thursday Afternoon Snow Level 5000' 4500' 5000' ' ' 4500' ' 5000'
Thursday Night - Friday Morning Snow Level 2500' 2500' 2000' ' ' 2500' ' 2500'
Friday Afternoon Snow Level 3500' 3500' 4000' ' ' 3500' ' 4000'
Hurricane Ridge Elevation
Thursday Morning Snow Level
3000'
Thursday Afternoon Snow Level
5000'
Thursday Night - Friday Morning Snow Level
2500'
Friday Afternoon Snow Level
3500'
Friday Night Snow Level
2500'
Mt. Baker Elevation
Thursday Morning Snow Level
3000'
Thursday Afternoon Snow Level
4500'
Thursday Night - Friday Morning Snow Level
2500'
Friday Afternoon Snow Level
3500'
Friday Night Snow Level
2500'
Washington Pass Elevation
Thursday Morning Snow Level
3500'
Thursday Afternoon Snow Level
5000'
Thursday Night - Friday Morning Snow Level
2000'
Friday Afternoon Snow Level
4000'
Friday Night Snow Level
2000'
Leavenworth Elevation
Thursday Morning Snow Level
'
Thursday Afternoon Snow Level
'
Thursday Night - Friday Morning Snow Level
'
Friday Afternoon Snow Level
'
Friday Night Snow Level
'
Stevens Pass Elevation
Thursday Morning Snow Level
'
Thursday Afternoon Snow Level
'
Thursday Night - Friday Morning Snow Level
'
Friday Afternoon Snow Level
'
Friday Night Snow Level
'
Snoqualmie Pass Elevation
Thursday Morning Snow Level
3000'
Thursday Afternoon Snow Level
4500'
Thursday Night - Friday Morning Snow Level
2500'
Friday Afternoon Snow Level
3500'
Friday Night Snow Level
2500'
Mt. Rainier & Crystal Elevation
Thursday Morning Snow Level
'
Thursday Afternoon Snow Level
'
Thursday Night - Friday Morning Snow Level
'
Friday Afternoon Snow Level
'
Friday Night Snow Level
'
Mt. Hood Elevation
Thursday Morning Snow Level
3000'
Thursday Afternoon Snow Level
5000'
Thursday Night - Friday Morning Snow Level
2500'
Friday Afternoon Snow Level
4000'
Friday 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

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

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Thursday Morning S 15 - 25 SSW 15 - 25 SW 5 - 15 --- - SW 10 - 20
Thursday Afternoon SW 10 - 20 SW 15 - 25 WSW 10 - 20 --- - WSW 10 - 20
Thursday Night - Friday Morning SW 5 - 15 SW 5 - 15 WSW 10 - 20 --- - WSW 15 - 25
Friday Afternoon SW 5 - 15 SW 5 - 15 WSW 15 - 25 --- - WSW 15 - 25
Hurricane Ridge Elevation
Thursday Morning S 15 - 25
Thursday Afternoon SW 10 - 20
Thursday Night - Friday Morning SW 5 - 15
Friday Afternoon SW 5 - 15
Friday Night SW 0 - 10
Mt. Baker Elevation
Thursday Morning SSW 15 - 25
Thursday Afternoon SW 15 - 25
Thursday Night - Friday Morning SW 5 - 15
Friday Afternoon SW 5 - 15
Friday Night SW 0 - 10
Stevens and Snoqualmie Pass Elevation
Thursday Morning SW 5 - 15
Thursday Afternoon WSW 10 - 20
Thursday Night - Friday Morning WSW 10 - 20
Friday Afternoon WSW 15 - 25
Friday Night WSW 10 - 20
Mt. Rainier Elevation
Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night - Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Mt. Hood Elevation
Thursday Morning SW 10 - 20
Thursday Afternoon WSW 10 - 20
Thursday Night - Friday Morning WSW 15 - 25
Friday Afternoon WSW 15 - 25
Friday Night WSW 10 - 20
Hurricane Ridge Direction - Speed
Thursday Morning S 15 - 25
Thursday Afternoon SW 10 - 20
Thursday Night - Friday Morning SW 5 - 15
Friday Afternoon SW 5 - 15
Friday Night SW 0 - 10
Mt. Baker Direction - Speed
Thursday Morning SSW 15 - 25
Thursday Afternoon SW 15 - 25
Thursday Night - Friday Morning SW 5 - 15
Friday Afternoon SW 5 - 15
Friday Night SW 0 - 10
Stevens and Snoqualmie Pass Direction - Speed
Thursday Morning SW 5 - 15
Thursday Afternoon WSW 10 - 20
Thursday Night - Friday Morning WSW 10 - 20
Friday Afternoon WSW 15 - 25
Friday Night WSW 10 - 20
Mt. Rainier Direction - Speed
Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night - Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Mt. Hood Direction - Speed
Thursday Morning SW 10 - 20
Thursday Afternoon WSW 10 - 20
Thursday Night - Friday Morning WSW 15 - 25
Friday Afternoon WSW 15 - 25
Friday Night WSW 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 Morning SW 10 - 20 SSE 10 - 20 SW 10 - 20 --- - SW 25 - 35
Thursday Afternoon SW 20 - 30 SW 10 - 20 SW 20 - 30 --- - SW 25 - 35
Thursday Night - Friday Morning SW 10 - 20 W 5 - 15 W 20 - 30 --- - W 20 - 30
Friday Afternoon W 10 - 20 W 10 - 20 WSW 20 - 30 --- - WSW 25 - 35
Mt. Baker Direction - Speed
Thursday Morning SW 10 - 20
Thursday Afternoon SW 20 - 30
Thursday Night - Friday Morning SW 10 - 20
Friday Afternoon W 10 - 20
Friday Afternoon - Friday Night W 10 - 20
Washington Pass Direction - Speed
Thursday Morning SSE 10 - 20
Thursday Afternoon SW 10 - 20
Thursday Night - Friday Morning W 5 - 15
Friday Afternoon W 10 - 20
Friday Afternoon - Friday Night W 15 - 25
Stevens and Snoqualmie Pass Direction - Speed
Thursday Morning SW 10 - 20
Thursday Afternoon SW 20 - 30
Thursday Night - Friday Morning W 20 - 30
Friday Afternoon WSW 20 - 30
Friday Afternoon - Friday Night W 15 - 25
Mt. Rainier Direction - Speed
Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night - Friday Morning --- -
Friday Afternoon --- -
Friday Afternoon - Friday Night --- -
Mt. Hood Direction - Speed
Thursday Morning SW 25 - 35
Thursday Afternoon SW 25 - 35
Thursday Night - Friday Morning W 20 - 30
Friday Afternoon WSW 25 - 35
Friday Afternoon - Friday Night W 20 - 30

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 Apr 10, 2017

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