Issued: 7:21 AM PDT Tuesday, March 27, 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 Tuesday & Friday

Disorganized warm frontal moisture continues to stream over a flattened upper level ridge in NW flow aloft and into Washington State. A secondary and final slug of moisture will arrive later this morning and spread more moderate precipitation into the southwest Cascades. In this pattern, significant rain-shadowing or downslope drying will occur on the leeward side of the Cascade and Olympic ranges.

Snow levels will slowly rise until an ill-defined frontal boundary passes through the Cascades later this afternoon. Snow levels should peak in the 4500-5000 ft range in the north Cascades and 5500-6000 in the south Washington Cascades and Mt. Hood. Mt. Hood will escape the bulk of the precipitation but not the strong westerly winds with this event.  Winds near Cascades crest level will stay elevated during the short term period. 

The upper level ridge will rebuild around 135 W on Wednesday but moisture from a weak system upstream off the northern British Columbia coast will slip clouds and perhaps even a little light rain and snow into the northwest Cascades during the day. The chance for light precipitation increases Wednesday night for the Olympics and central/south Washington Cascades as the frontal boundary slowly sags south and collapses the upper level ridge. 

Weather Forecast

Olympics
Tuesday Light to moderate rain and snow, heaviest west slopes of the Olympics. Slow warming trend. Breezy.
Tuesday Night Cloudy with scattered light rain and snow showers quickly tapering down in the evening. Becoming mostly cloudy after midnight. Cooling trend.
Wednesday Cloudy.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Tuesday Light to moderate rain and snow, heaviest Snoqualmie Pass and Paradise. Slow warming trend. Windy.
Tuesday Night Cloudy with light to occasionally moderate rain and snow showers quickly tapering down in the evening. Becoming mostly cloudy after midnight. Cooling trend. Moderate to strong alpine winds.
Wednesday Periods of very light rain and snow Mt. Baker area. Cloudy elsewhere. Moderate alpine winds.
East Slopes of the Washington Cascades
Tuesday Periods of light rain and snow, occasionally becoming moderate near the Cascade crest. Slow warming trend. Windy.
Tuesday Night Mostly cloudy with light rain and snow showers quickly tapering down in the evening. Cooling trend. Moderate to strong alpine winds.
Wednesday Partly to mostly cloudy. Moderate alpine winds.
Mt. Hood
Tuesday Cloudy with periods of light rain and snow. Slow warming trend. Windy.
Tuesday Night Cloudy with light rain and snow showers quickly tapering down in the evening. Becoming mostly cloudy after midnight. Cooling trend. Moderate alpine winds.
Wednesday Partly to mostly cloudy. Moderate alpine winds.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Tuesday Morning Snow Level 5000' 3500' 3500' ' ' 4000' ' 4000'
Tuesday Afternoon Snow Level 6000' 4500' 4500' ' ' 5000' ' 6000'
Tuesday Night Snow Level 3500' 2500' 2500' ' ' 3500' ' 4500'
Wednesday Morning Snow Level 2000' 2000' 2000' ' ' 2500' ' 4000'
Wednesday Afternoon Snow Level 4000' 3000' 3000' ' ' 3500' ' 5500'
Hurricane Ridge Elevation
Tuesday Morning Snow Level
5000'
Tuesday Afternoon Snow Level
6000'
Tuesday Night Snow Level
3500'
Wednesday Morning Snow Level
2000'
Wednesday Afternoon Snow Level
4000'
Wednesday Night Snow Level
4000'
Mt. Baker Elevation
Tuesday Morning Snow Level
3500'
Tuesday Afternoon Snow Level
4500'
Tuesday Night Snow Level
2500'
Wednesday Morning Snow Level
2000'
Wednesday Afternoon Snow Level
3000'
Wednesday Night Snow Level
2500'
Washington Pass Elevation
Tuesday Morning Snow Level
3500'
Tuesday Afternoon Snow Level
4500'
Tuesday Night Snow Level
2500'
Wednesday Morning Snow Level
2000'
Wednesday Afternoon Snow Level
3000'
Wednesday Night Snow Level
2500'
Leavenworth Elevation
Tuesday Morning Snow Level
'
Tuesday Afternoon Snow Level
'
Tuesday Night Snow Level
'
Wednesday Morning Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Stevens Pass Elevation
Tuesday Morning Snow Level
'
Tuesday Afternoon Snow Level
'
Tuesday Night Snow Level
'
Wednesday Morning Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Snoqualmie Pass Elevation
Tuesday Morning Snow Level
4000'
Tuesday Afternoon Snow Level
5000'
Tuesday Night Snow Level
3500'
Wednesday Morning Snow Level
2500'
Wednesday Afternoon Snow Level
3500'
Wednesday Night Snow Level
3000'
Mt. Rainier & Crystal Elevation
Tuesday Morning Snow Level
'
Tuesday Afternoon Snow Level
'
Tuesday Night Snow Level
'
Wednesday Morning Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Mt. Hood Elevation
Tuesday Morning Snow Level
4000'
Tuesday Afternoon Snow Level
6000'
Tuesday Night Snow Level
4500'
Wednesday Morning Snow Level
4000'
Wednesday Afternoon Snow Level
5500'
Wednesday Night Snow Level
5500'

* 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 0.25 LT 0.10
Mt Baker Ski Area 0.50 - 0.75 LT 0.25
Washington Pass LT 0.25 LT 0.10
Stevens Pass 0 - 0.75 LT 0.10
Snoqualmie Pass 1.00 - 1.50 LT 0.10
Mission Ridge LT 0.10 LT 0.10
Crystal Mt LT 0.25 LT 0.10
Paradise 0 - 1.00 LT 0.10
White Pass LT 0.25 LT 0.10
Mt Hood Meadows LT 0.10 LT 0.10
LT 0.25 LT 0.10

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Tuesday Morning S 15 - 25 S 20 - 30 SW 20 - 30 --- - WSW 15 - 25
Tuesday Afternoon WSW 20 - 30 SW 20 - 30 WSW 20 - 40 --- - W 25 - 35
Tuesday Night W 10 - 20 SW 10 - 20 WSW 15 - 25 --- - W 25 - 35
Wednesday Morning W 10 - 20 SW 5 - 15 W 10 - 20 --- - W 20 - 30
Wednesday Afternoon W 10 - 20 SW 5 - 15 W 10 - 20 --- - W 15 - 25
Hurricane Ridge Elevation
Tuesday Morning S 15 - 25
Tuesday Afternoon WSW 20 - 30
Tuesday Night W 10 - 20
Wednesday Morning W 10 - 20
Wednesday Afternoon W 10 - 20
Wednesday Night W 5 - 15
Mt. Baker Elevation
Tuesday Morning S 20 - 30
Tuesday Afternoon SW 20 - 30
Tuesday Night SW 10 - 20
Wednesday Morning SW 5 - 15
Wednesday Afternoon SW 5 - 15
Wednesday Night SW 5 - 15
Stevens and Snoqualmie Pass Elevation
Tuesday Morning SW 20 - 30
Tuesday Afternoon WSW 20 - 40
Tuesday Night WSW 15 - 25
Wednesday Morning W 10 - 20
Wednesday Afternoon W 10 - 20
Wednesday Night W 5 - 15
Mt. Rainier Elevation
Tuesday Morning --- -
Tuesday Afternoon --- -
Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night --- -
Mt. Hood Elevation
Tuesday Morning WSW 15 - 25
Tuesday Afternoon W 25 - 35
Tuesday Night W 25 - 35
Wednesday Morning W 20 - 30
Wednesday Afternoon W 15 - 25
Wednesday Night WNW 10 - 20
Hurricane Ridge Direction - Speed
Tuesday Morning S 15 - 25
Tuesday Afternoon WSW 20 - 30
Tuesday Night W 10 - 20
Wednesday Morning W 10 - 20
Wednesday Afternoon W 10 - 20
Wednesday Night W 5 - 15
Mt. Baker Direction - Speed
Tuesday Morning S 20 - 30
Tuesday Afternoon SW 20 - 30
Tuesday Night SW 10 - 20
Wednesday Morning SW 5 - 15
Wednesday Afternoon SW 5 - 15
Wednesday Night SW 5 - 15
Stevens and Snoqualmie Pass Direction - Speed
Tuesday Morning SW 20 - 30
Tuesday Afternoon WSW 20 - 40
Tuesday Night WSW 15 - 25
Wednesday Morning W 10 - 20
Wednesday Afternoon W 10 - 20
Wednesday Night W 5 - 15
Mt. Rainier Direction - Speed
Tuesday Morning --- -
Tuesday Afternoon --- -
Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night --- -
Mt. Hood Direction - Speed
Tuesday Morning WSW 15 - 25
Tuesday Afternoon W 25 - 35
Tuesday Night W 25 - 35
Wednesday Morning W 20 - 30
Wednesday Afternoon W 15 - 25
Wednesday Night WNW 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
Tuesday Morning WSW 35 - 45 WSW 45 - 55 W 35 - 50 --- - NW 30 - 40
Tuesday Afternoon W 30 - 40 W 50 - 60 WNW 45 - 55 --- - NW 45 - 55
Tuesday Night WNW 35 - 45 W 35 - 45 NW 50 - 60 --- - NW 45 - 55
Wednesday Morning WNW 35 - 45 NW 25 - 35 NW 45 - 55 --- - NW 35 - 45
Wednesday Afternoon NW 35 - 45 NW 25 - 35 NW 40 - 50 --- - NW 40 - 50
Mt. Baker Direction - Speed
Tuesday Morning WSW 35 - 45
Tuesday Afternoon W 30 - 40
Tuesday Night WNW 35 - 45
Wednesday Morning WNW 35 - 45
Wednesday Afternoon NW 35 - 45
Wednesday Night NW 25 - 35
Washington Pass Direction - Speed
Tuesday Morning WSW 45 - 55
Tuesday Afternoon W 50 - 60
Tuesday Night W 35 - 45
Wednesday Morning NW 25 - 35
Wednesday Afternoon NW 25 - 35
Wednesday Night NW 20 - 30
Stevens and Snoqualmie Pass Direction - Speed
Tuesday Morning W 35 - 50
Tuesday Afternoon WNW 45 - 55
Tuesday Night NW 50 - 60
Wednesday Morning NW 45 - 55
Wednesday Afternoon NW 40 - 50
Wednesday Night NW 35 - 45
Mt. Rainier Direction - Speed
Tuesday Morning --- -
Tuesday Afternoon --- -
Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night --- -
Mt. Hood Direction - Speed
Tuesday Morning NW 30 - 40
Tuesday Afternoon NW 45 - 55
Tuesday Night NW 45 - 55
Wednesday Morning NW 35 - 45
Wednesday Afternoon NW 40 - 50
Wednesday Night NW 35 - 45

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 Mar 26, 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.