Issued: 7:36 AM PST Wednesday, February 14, 2018
by Robert Hahn

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

Weather Synopsis for Wednesday & Friday

On Wednesday morning, a shortwave trough embedded in Northwest flow aloft is sliding over the Pacific Northwest and has replaced a tongue of Tuesday's offshore high pressure ridge which had kept us under warm and generally fair weather. The relatively stationary Pacific High pressure dominates all but the peripheries of the North Pacific Ocean.

A surface cold front passed to our east on Tuesday night, brought a significant decrease in temperatures (now most stations are in the 20's and 10's) with decreasing post-frontal westerly flow and generally decreasing light to moderate snow showers. A band of heavier convergence is currently moving south of Stevens pass toward Snoqualmie pass. Snow showers will be heaviest along the west slopes of the Cascades from the central Cascades to Mt. Hood. Any snow shower activity should be light by the afternoon and most areas will see snow showers ending by evening. 

Upper-level northwest flow will continue with a break between the systems generally Wednesday night through Thursday, with some very light snow shower activity continuing in the Mt. Hood area during this period.

Thursday night, another upper shortwave approaches from the northwest, spreading increasing light to occasional moderate snow into the region. The brunt of this system won't arrive until daylight hours on Friday.

Weather Forecast

Olympics
Wednesday Light snow showers ending early, leaving decreasing clouds with mostly sunny conditions by afternoon.
Wednesday Night Mostly clear with increasing high clouds toward morning.
Thursday High clouds.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Wednesday Decreasing light snow showers during the morning hours in the north, then becoming partly sunny. Decreasing light to moderate snow showers in the morning, central and south, with some convergence from Stevens to Snoqualmie. Very light snow showers decreasing in the afternoon with some sun breaks.
Wednesday Night Mostly cloudy with chance of a very light snow shower central and south. Mostly clear, north.
Thursday Increasing high clouds throughout, with scattered low clouds central and south. Light snow developing late in the central and south parts.
East Slopes of the Washington Cascades
Wednesday Becoming partly sunny in the north. Decreasing light snow showers in the morning, central and south.
Wednesday Night Mostly clear with some clouds near the crest, central and south.
Thursday Increasing high clouds
Mt. Hood
Wednesday Moderate snow showers decreasing late morning and becoming light during the afternoon.
Wednesday Night Mostly cloudy with isolated, light snow showers.
Thursday Mostly cloudy with light snow showers.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Wednesday Morning Snow Level 1000' 1000' 1500' ' ' 2000' ' 2000'
Wednesday Afternoon Snow Level 2500' 2000' 2000' ' ' 2000' ' 2500'
Wednesday Night Snow Level 1500' 1000' 500' ' ' 1000' ' 2000'
Thursday Morning Snow Level 1500' 1000' 1000' ' ' 2000' ' 2000'
Thursday Afternoon Snow Level 2000' 1500' 1500' ' ' 2000' ' 2500'
Hurricane Ridge Elevation
Wednesday Morning Snow Level
1000'
Wednesday Afternoon Snow Level
2500'
Wednesday Night Snow Level
1500'
Thursday Morning Snow Level
1500'
Thursday Afternoon Snow Level
2000'
Thursday Night Snow Level
1500'
Mt. Baker Elevation
Wednesday Morning Snow Level
1000'
Wednesday Afternoon Snow Level
2000'
Wednesday Night Snow Level
1000'
Thursday Morning Snow Level
1000'
Thursday Afternoon Snow Level
1500'
Thursday Night Snow Level
1500'
Washington Pass Elevation
Wednesday Morning Snow Level
1500'
Wednesday Afternoon Snow Level
2000'
Wednesday Night Snow Level
500'
Thursday Morning Snow Level
1000'
Thursday Afternoon Snow Level
1500'
Thursday Night Snow Level
1500'
Leavenworth Elevation
Wednesday Morning Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Thursday Morning Snow Level
'
Thursday Afternoon Snow Level
'
Thursday Night Snow Level
'
Stevens Pass Elevation
Wednesday Morning Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Thursday Morning Snow Level
'
Thursday Afternoon Snow Level
'
Thursday Night Snow Level
'
Snoqualmie Pass Elevation
Wednesday Morning Snow Level
2000'
Wednesday Afternoon Snow Level
2000'
Wednesday Night Snow Level
1000'
Thursday Morning Snow Level
2000'
Thursday Afternoon Snow Level
2000'
Thursday Night Snow Level
2000'
Mt. Rainier & Crystal Elevation
Wednesday Morning Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Thursday Morning Snow Level
'
Thursday Afternoon Snow Level
'
Thursday Night Snow Level
'
Mt. Hood Elevation
Wednesday Morning Snow Level
2000'
Wednesday Afternoon Snow Level
2500'
Wednesday Night Snow Level
2000'
Thursday Morning Snow Level
2000'
Thursday Afternoon Snow Level
2500'
Thursday Night Snow Level
2000'

* 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

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

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Wednesday Morning WNW 10 - 20 NE 5 - 15 WSW 10 - 20 --- - W 20 - 30
Wednesday Afternoon WNW 5 - 15 WNW 5 - 15 W 10 - 20 --- - W 20 - 30
Wednesday Night WNW 5 - 15 WNW 5 - 15 W 5 - 15 --- - W 20 - 30
Thursday Morning WSW 5 - 15 SSW 5 - 15 WNW 5 - 15 --- - W 15 - 25
Thursday Afternoon WSW 10 - 20 SSW 10 - 20 WSW 15 - 25 --- - WSW 20 - 30
Hurricane Ridge Elevation
Wednesday Morning WNW 10 - 20
Wednesday Afternoon WNW 5 - 15
Wednesday Night WNW 5 - 15
Thursday Morning WSW 5 - 15
Thursday Afternoon WSW 10 - 20
Thursday Night WSW 20 - 30
Mt. Baker Elevation
Wednesday Morning NE 5 - 15
Wednesday Afternoon WNW 5 - 15
Wednesday Night WNW 5 - 15
Thursday Morning SSW 5 - 15
Thursday Afternoon SSW 10 - 20
Thursday Night SW 15 - 25
Stevens and Snoqualmie Pass Elevation
Wednesday Morning WSW 10 - 20
Wednesday Afternoon W 10 - 20
Wednesday Night W 5 - 15
Thursday Morning WNW 5 - 15
Thursday Afternoon WSW 15 - 25
Thursday Night WSW 20 - 30
Mt. Rainier Elevation
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night --- -
Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night --- -
Mt. Hood Elevation
Wednesday Morning W 20 - 30
Wednesday Afternoon W 20 - 30
Wednesday Night W 20 - 30
Thursday Morning W 15 - 25
Thursday Afternoon WSW 20 - 30
Thursday Night WSW 25 - 35
Hurricane Ridge Direction - Speed
Wednesday Morning WNW 10 - 20
Wednesday Afternoon WNW 5 - 15
Wednesday Night WNW 5 - 15
Thursday Morning WSW 5 - 15
Thursday Afternoon WSW 10 - 20
Thursday Night WSW 20 - 30
Mt. Baker Direction - Speed
Wednesday Morning NE 5 - 15
Wednesday Afternoon WNW 5 - 15
Wednesday Night WNW 5 - 15
Thursday Morning SSW 5 - 15
Thursday Afternoon SSW 10 - 20
Thursday Night SW 15 - 25
Stevens and Snoqualmie Pass Direction - Speed
Wednesday Morning WSW 10 - 20
Wednesday Afternoon W 10 - 20
Wednesday Night W 5 - 15
Thursday Morning WNW 5 - 15
Thursday Afternoon WSW 15 - 25
Thursday Night WSW 20 - 30
Mt. Rainier Direction - Speed
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night --- -
Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night --- -
Mt. Hood Direction - Speed
Wednesday Morning W 20 - 30
Wednesday Afternoon W 20 - 30
Wednesday Night W 20 - 30
Thursday Morning W 15 - 25
Thursday Afternoon WSW 20 - 30
Thursday Night WSW 25 - 35

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
Wednesday Morning NE 5 - 15 N 15 - 25 WNW 15 - 25 --- - W 35 - 50
Wednesday Afternoon NW 10 - 20 NW 15 - 25 NW 20 - 30 --- - WNW 30 - 40
Wednesday Night NW 15 - 25 NW 15 - 25 NW 30 - 40 --- - NW 30 - 40
Thursday Morning W 10 - 20 W 10 - 20 WNW 15 - 25 --- - NW 20 - 30
Thursday Afternoon WSW 15 - 25 WSW 15 - 25 W 20 - 30 --- - W 25 - 35
Mt. Baker Direction - Speed
Wednesday Morning NE 5 - 15
Wednesday Afternoon NW 10 - 20
Wednesday Night NW 15 - 25
Thursday Morning W 10 - 20
Thursday Afternoon WSW 15 - 25
Thursday Night WSW 30 - 40
Washington Pass Direction - Speed
Wednesday Morning N 15 - 25
Wednesday Afternoon NW 15 - 25
Wednesday Night NW 15 - 25
Thursday Morning W 10 - 20
Thursday Afternoon WSW 15 - 25
Thursday Night WSW 35 - 50
Stevens and Snoqualmie Pass Direction - Speed
Wednesday Morning WNW 15 - 25
Wednesday Afternoon NW 20 - 30
Wednesday Night NW 30 - 40
Thursday Morning WNW 15 - 25
Thursday Afternoon W 20 - 30
Thursday Night W 40 - 60
Mt. Rainier Direction - Speed
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night --- -
Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night --- -
Mt. Hood Direction - Speed
Wednesday Morning W 35 - 50
Wednesday Afternoon WNW 30 - 40
Wednesday Night NW 30 - 40
Thursday Morning NW 20 - 30
Thursday Afternoon W 25 - 35
Thursday Night WNW 35 - 50

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 Feb 13, 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.