Issued: 7:44 AM PDT Thursday, April 5, 2018
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 & Wednesday

A deep low pressure system well off the B.C. coast is spinning a N-S oriented front into the Pacific Northwest today. Light rain and snow already gracing the area will only increase in the afternoon as the front slowly works across the Cascades through the early evening. Snow levels hanging around 4500 ft in the north and 6000 ft at Mt. Hood this morning will slightly rise through the day. More moderate precipitation will continue through the evening hours before tapering down overnight.  

Friday is a relative break day with a dirty ridge building over the inland Pacific Northwest and the main tap of moisture aimed into northern California. A few periods of light rain are likely Friday. The south and central Cascades will likely see a few sunbreaks Friday morning through mid-day, with cloudier conditions expected over the north Cascades and down at Mt. Hood. Milder air will continue to work into the region. 

An impressive and developing low pressure system offshore will track NE toward Vancouver Island Friday night. The approaching frontal band will likely bring stormy conditions to the Cascades by early Saturday morning with snow levels peaking Friday night. The highest snow levels are currently pegged for the Olympics, and Snoqualmie Pass and southward. Offshore gradients will increase Friday night, but the air mass is too warm for easterly flow to have any cooling effect in the Passes. 

Weather Forecast

Olympics
Thursday Light rain and snow becoming light to occasionally moderate rain and snow in the afternoon.
Thursday Night Light rain and snow becoming cloudy with periods of light rain and snow in the evening.
Friday Mostly cloudy. Periods of light rain and snow. Milder.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Thursday Light rain and snow becoming light to moderate rain and snow in the afternoon.
Thursday Night Light to moderate rain and snow becoming light after midnight.
Friday Mostly cloudy. Periods of light rain and snow. Milder.
East Slopes of the Washington Cascades
Thursday Light rain and snow becoming light to moderate rain and snow in the afternoon.
Thursday Night Light to moderate rain and snow becoming light after midnight.
Friday Mostly cloudy southeast and central-east, cloudy north. Periods of light rain and snow. Milder.
Mt. Hood
Thursday Light rain and snow becoming light to moderate rain and snow in the afternoon.
Thursday Night Light to moderate rain and snow becoming light after midnight.
Friday Cloudy. Periods of light rain and snow. Milder.

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 5500' 4500' 4000' ' ' 5000' ' 6000'
Thursday Afternoon Snow Level 6000' 5000' 5000' ' ' 5500' ' 6500'
Thursday Night Snow Level 6000' 6000' 5000' ' ' 6500' ' 7000'
Friday Morning Snow Level 5500' 5500' 5000' ' ' 6000' ' 7000'
Friday Afternoon Snow Level 6500' 6500' 6500' ' ' 7000' ' 8000'
Friday Night Snow Level 8500' 6500' 6000' ' ' 8500' ' 10000'
Hurricane Ridge Elevation
Thursday Morning Snow Level
5500'
Thursday Afternoon Snow Level
6000'
Thursday Night Snow Level
6000'
Friday Morning Snow Level
5500'
Friday Afternoon Snow Level
6500'
Friday Night Snow Level
8500'
Thursday Evening Snow Level
6500'
Mt. Baker Elevation
Thursday Morning Snow Level
4500'
Thursday Afternoon Snow Level
5000'
Thursday Night Snow Level
6000'
Friday Morning Snow Level
5500'
Friday Afternoon Snow Level
6500'
Friday Night Snow Level
6500'
Thursday Evening Snow Level
5500'
Washington Pass Elevation
Thursday Morning Snow Level
4000'
Thursday Afternoon Snow Level
5000'
Thursday Night Snow Level
5000'
Friday Morning Snow Level
5000'
Friday Afternoon Snow Level
6500'
Friday Night Snow Level
6000'
Thursday Evening Snow Level
5500'
Leavenworth Elevation
Thursday Morning Snow Level
'
Thursday Afternoon Snow Level
'
Thursday Night Snow Level
'
Friday Morning Snow Level
'
Friday Afternoon Snow Level
'
Friday Night Snow Level
'
Thursday Evening Snow Level
'
Stevens Pass Elevation
Thursday Morning Snow Level
'
Thursday Afternoon Snow Level
'
Thursday Night Snow Level
'
Friday Morning Snow Level
'
Friday Afternoon Snow Level
'
Friday Night Snow Level
'
Thursday Evening Snow Level
'
Snoqualmie Pass Elevation
Thursday Morning Snow Level
5000'
Thursday Afternoon Snow Level
5500'
Thursday Night Snow Level
6500'
Friday Morning Snow Level
6000'
Friday Afternoon Snow Level
7000'
Friday Night Snow Level
8500'
Thursday Evening Snow Level
6000'
Mt. Rainier & Crystal Elevation
Thursday Morning Snow Level
'
Thursday Afternoon Snow Level
'
Thursday Night Snow Level
'
Friday Morning Snow Level
'
Friday Afternoon Snow Level
'
Friday Night Snow Level
'
Thursday Evening Snow Level
'
Mt. Hood Elevation
Thursday Morning Snow Level
6000'
Thursday Afternoon Snow Level
6500'
Thursday Night Snow Level
7000'
Friday Morning Snow Level
7000'
Friday Afternoon Snow Level
8000'
Friday Night Snow Level
10000'
Thursday Evening Snow Level
7000'

* 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 LT 0.25 LT 0.25
Mt Baker Ski Area 0.75 - 1.00 0.25 - 0.50
Washington Pass 0 - 0.50 LT 0.25
Stevens Pass 0 - 0.75 0.25 - 0.50
Snoqualmie Pass 0 - 1.00 0 - 0.50
Mission Ridge 0.25 - 0.50 0.25 - 0.50
Crystal Mt 0 - 0.75 0 - 0.50
Paradise 1.00 - 1.50 0 - 0.75
White Pass 0 - 0.50 0.25 - 0.50
Mt Hood Meadows 0 - 1.00 0 - 1.00
1.00 - 1.50 0 - 1.00

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Thursday Morning S 10 - 20 S 15 - 30 SE 5 - 15 --- - SSW 5 - 15
Thursday Afternoon SSW 15 - 25 SSE 10 - 20 SSE 10 - 20 --- - SW 5 - 15
Thursday Night S 10 - 20 S 10 - 20 SW 15 - 25 --- - WSW 10 - 20
Friday Morning S 5 - 15 SSE 10 - 20 S 5 - 15 --- - SSE 0 - 10
Friday Afternoon SE 5 - 15 SE 5 - 15 SE 5 - 15 --- - SE 5 - 15
Hurricane Ridge Elevation
Thursday Morning S 10 - 20
Thursday Afternoon SSW 15 - 25
Thursday Night S 10 - 20
Friday Morning S 5 - 15
Friday Afternoon SE 5 - 15
Friday Night ESE 15 - 25
Mt. Baker Elevation
Thursday Morning S 15 - 30
Thursday Afternoon SSE 10 - 20
Thursday Night S 10 - 20
Friday Morning SSE 10 - 20
Friday Afternoon SE 5 - 15
Friday Night E 10 - 20
Stevens and Snoqualmie Pass Elevation
Thursday Morning SE 5 - 15
Thursday Afternoon SSE 10 - 20
Thursday Night SW 15 - 25
Friday Morning S 5 - 15
Friday Afternoon SE 5 - 15
Friday Night E 15 - 25
Mt. Rainier Elevation
Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night --- -
Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Mt. Hood Elevation
Thursday Morning SSW 5 - 15
Thursday Afternoon SW 5 - 15
Thursday Night WSW 10 - 20
Friday Morning SSE 0 - 10
Friday Afternoon SE 5 - 15
Friday Night E 10 - 20
Hurricane Ridge Direction - Speed
Thursday Morning S 10 - 20
Thursday Afternoon SSW 15 - 25
Thursday Night S 10 - 20
Friday Morning S 5 - 15
Friday Afternoon SE 5 - 15
Friday Night ESE 15 - 25
Mt. Baker Direction - Speed
Thursday Morning S 15 - 30
Thursday Afternoon SSE 10 - 20
Thursday Night S 10 - 20
Friday Morning SSE 10 - 20
Friday Afternoon SE 5 - 15
Friday Night E 10 - 20
Stevens and Snoqualmie Pass Direction - Speed
Thursday Morning SE 5 - 15
Thursday Afternoon SSE 10 - 20
Thursday Night SW 15 - 25
Friday Morning S 5 - 15
Friday Afternoon SE 5 - 15
Friday Night E 15 - 25
Mt. Rainier Direction - Speed
Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night --- -
Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Mt. Hood Direction - Speed
Thursday Morning SSW 5 - 15
Thursday Afternoon SW 5 - 15
Thursday Night WSW 10 - 20
Friday Morning SSE 0 - 10
Friday Afternoon SE 5 - 15
Friday Night E 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 SSW 20 - 30 SW 15 - 25 SW 25 - 35 --- - SW 25 - 35
Thursday Afternoon SSW 15 - 30 SW 10 - 20 SW 25 - 35 --- - SW 25 - 35
Thursday Night SW 15 - 25 SW 10 - 20 WSW 20 - 30 --- - SW 20 - 30
Friday Morning SW 10 - 20 SW 10 - 20 SW 10 - 20 --- - SW 10 - 20
Friday Afternoon S 10 - 20 SW 5 - 15 SW 10 - 20 --- - S 10 - 20
Mt. Baker Direction - Speed
Thursday Morning SSW 20 - 30
Thursday Afternoon SSW 15 - 30
Thursday Night SW 15 - 25
Friday Morning SW 10 - 20
Friday Afternoon S 10 - 20
Friday Night SSE 15 - 25
Washington Pass Direction - Speed
Thursday Morning SW 15 - 25
Thursday Afternoon SW 10 - 20
Thursday Night SW 10 - 20
Friday Morning SW 10 - 20
Friday Afternoon SW 5 - 15
Friday Night SSE 10 - 20
Stevens and Snoqualmie Pass Direction - Speed
Thursday Morning SW 25 - 35
Thursday Afternoon SW 25 - 35
Thursday Night WSW 20 - 30
Friday Morning SW 10 - 20
Friday Afternoon SW 10 - 20
Friday Night S 25 - 40
Mt. Rainier Direction - Speed
Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night --- -
Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Mt. Hood Direction - Speed
Thursday Morning SW 25 - 35
Thursday Afternoon SW 25 - 35
Thursday Night SW 20 - 30
Friday Morning SW 10 - 20
Friday Afternoon S 10 - 20
Friday Night SW 30 - 40

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 1, 2018

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.