Issued: 7:13 AM PST Sunday, February 18, 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 Sunday & Tuesday

The Pacific Northwest will be in cold northerly flow aloft as the Pacific upper level ridge stays parked near 145W and the longwave upper level trough associated with Saturday's storm system begins to dig south and east over the next 48 hours. 

Weak surface low pressure SE of the Olympics and off the Washington Coast will continue to stream snow showers into the SW Cascades and Mt. Hood through this afternoon, with the heaviest accumulations likely from Mt. Rainier and south, and especially at Mt. Hood. Northerly winds from Fraser Outflow is picking up moisture across the Strait of Juan de Fuca and delivering some light upslope snow to the north slopes of the Olympics. Upslope snow showers seen against the northeast Cascades should shift south during the day and deliver some light snowfall particularly to the Mission Ridge area.  Drier and much colder air moving in from the north should allow some clearing for the north Cascades in the afternoon. High pressure over the interior of British Columbia will help drive down the coldest air mass seen this season over our area. 

The weather will be fair Monday and Monday night, with some clouds likely trapped below ridgecrest specific to the west slopes of the Cascades and Mt. Hood, and clearer skies expected elsewhere. 

Weather Forecast

Olympics
Sunday Light to occasionally moderate snow showers becoming mostly cloudy with scattered light snow showers in the afternoon. Colder.
Sunday Night Partly cloudy. Cold.
Monday Mostly sunny. Cold.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Sunday Light snow showers this morning, occasionally moderate Mt. Rainier to White Pass. Light showers becoming scattered in the afternoon with partial clearing in the north Cascades. Colder.
Sunday Night Partly to mostly cloudy with isolated light snow showers ending late tonight. Cold.
Monday Partly cloudy. Cold.
East Slopes of the Washington Cascades
Sunday Light snow showers NE Cascades becoming scattered in the afternoon with partial clearing. Light to occasionally moderate snow showers developing central-east and southeast Cascades late morning. Colder.
Sunday Night Partly to mostly cloudy with isolated light snow showers ending late tonight. Cold.
Monday Partly to mostly sunny. Cold.
Mt. Hood
Sunday Light to moderate snow showers, tapering slightly in the afternoon. Winds decreasing in the afternoon. Colder.
Sunday Night Mostly cloudy with scattered light snow showers ending late tonight. Cold.
Monday Partly cloudy. Cold.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Sunday Snow Level 0' 0' 0' ' ' 0' ' 500'
Sunday Night Snow Level 0' 0' 0' ' ' 0' ' 0'
Monday Freezing Level 0' 0' 0' ' ' 0' ' 0'
Hurricane Ridge Elevation
Sunday Snow Level
0'
Sunday Night Snow Level
0'
Monday Freezing Level
0'
Monday Night Freezing Level
0'
Mt. Baker Elevation
Sunday Snow Level
0'
Sunday Night Snow Level
0'
Monday Freezing Level
0'
Monday Night Freezing Level
0'
Washington Pass Elevation
Sunday Snow Level
0'
Sunday Night Snow Level
0'
Monday Freezing Level
0'
Monday Night Freezing Level
0'
Leavenworth Elevation
Sunday Snow Level
'
Sunday Night Snow Level
'
Monday Freezing Level
'
Monday Night Freezing Level
'
Stevens Pass Elevation
Sunday Snow Level
'
Sunday Night Snow Level
'
Monday Freezing Level
'
Monday Night Freezing Level
'
Snoqualmie Pass Elevation
Sunday Snow Level
0'
Sunday Night Snow Level
0'
Monday Freezing Level
0'
Monday Night Freezing Level
0'
Mt. Rainier & Crystal Elevation
Sunday Snow Level
'
Sunday Night Snow Level
'
Monday Freezing Level
'
Monday Night Freezing Level
'
Mt. Hood Elevation
Sunday Snow Level
500'
Sunday Night Snow Level
0'
Monday Freezing Level
0'
Monday Night Freezing Level
0'

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

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Sunday Morning NNE 10 - 20 NE 10 - 20 WSW 5 - 15 --- - WSW 20 - 30
Sunday Afternoon NNE 15 - 25 NE 15 - 25 NW 5 - 15 --- - SW 10 - 20
Sunday Night NE 15 - 25 NE 10 - 20 NE 0 - 10 --- - NE 5 - 15
Monday Morning NE 5 - 15 NE 10 - 20 VAR 0 - 10 --- - E 5 - 15
Monday Afternoon N 0 - 10 NE 0 - 10 NW 0 - 10 --- - VAR 0 - 10
Hurricane Ridge Elevation
Sunday Morning NNE 10 - 20
Sunday Afternoon NNE 15 - 25
Sunday Night NE 15 - 25
Monday Morning NE 5 - 15
Monday Afternoon N 0 - 10
Monday Night W 0 - 10
Mt. Baker Elevation
Sunday Morning NE 10 - 20
Sunday Afternoon NE 15 - 25
Sunday Night NE 10 - 20
Monday Morning NE 10 - 20
Monday Afternoon NE 0 - 10
Monday Night W 0 - 10
Stevens and Snoqualmie Pass Elevation
Sunday Morning WSW 5 - 15
Sunday Afternoon NW 5 - 15
Sunday Night NE 0 - 10
Monday Morning VAR 0 - 10
Monday Afternoon NW 0 - 10
Monday Night W 0 - 10
Mt. Rainier Elevation
Sunday Morning --- -
Sunday Afternoon --- -
Sunday Night --- -
Monday Morning --- -
Monday Afternoon --- -
Monday Night --- -
Mt. Hood Elevation
Sunday Morning WSW 20 - 30
Sunday Afternoon SW 10 - 20
Sunday Night NE 5 - 15
Monday Morning E 5 - 15
Monday Afternoon VAR 0 - 10
Monday Night W 0 - 10
Hurricane Ridge Direction - Speed
Sunday Morning NNE 10 - 20
Sunday Afternoon NNE 15 - 25
Sunday Night NE 15 - 25
Monday Morning NE 5 - 15
Monday Afternoon N 0 - 10
Monday Night W 0 - 10
Mt. Baker Direction - Speed
Sunday Morning NE 10 - 20
Sunday Afternoon NE 15 - 25
Sunday Night NE 10 - 20
Monday Morning NE 10 - 20
Monday Afternoon NE 0 - 10
Monday Night W 0 - 10
Stevens and Snoqualmie Pass Direction - Speed
Sunday Morning WSW 5 - 15
Sunday Afternoon NW 5 - 15
Sunday Night NE 0 - 10
Monday Morning VAR 0 - 10
Monday Afternoon NW 0 - 10
Monday Night W 0 - 10
Mt. Rainier Direction - Speed
Sunday Morning --- -
Sunday Afternoon --- -
Sunday Night --- -
Monday Morning --- -
Monday Afternoon --- -
Monday Night --- -
Mt. Hood Direction - Speed
Sunday Morning WSW 20 - 30
Sunday Afternoon SW 10 - 20
Sunday Night NE 5 - 15
Monday Morning E 5 - 15
Monday Afternoon VAR 0 - 10
Monday Night W 0 - 10

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
Sunday Morning NE 10 - 20 N 10 - 20 WSW 10 - 20 --- - WSW 35 - 45
Sunday Afternoon NE 15 - 25 NE 15 - 25 NE 0 - 10 --- - WSW 25 - 35
Sunday Night ENE 15 - 25 N 10 - 20 NW 5 - 15 --- - NW 5 - 15
Monday Morning NE 20 - 30 N 15 - 25 NNW 10 - 20 --- - NW 5 - 15
Monday Afternoon N 15 - 25 N 15 - 25 NNW 15 - 25 --- - NW 10 - 20
Mt. Baker Direction - Speed
Sunday Morning NE 10 - 20
Sunday Afternoon NE 15 - 25
Sunday Night ENE 15 - 25
Monday Morning NE 20 - 30
Monday Afternoon N 15 - 25
Monday Night NW 10 - 20
Washington Pass Direction - Speed
Sunday Morning N 10 - 20
Sunday Afternoon NE 15 - 25
Sunday Night N 10 - 20
Monday Morning N 15 - 25
Monday Afternoon N 15 - 25
Monday Night NW 10 - 20
Stevens and Snoqualmie Pass Direction - Speed
Sunday Morning WSW 10 - 20
Sunday Afternoon NE 0 - 10
Sunday Night NW 5 - 15
Monday Morning NNW 10 - 20
Monday Afternoon NNW 15 - 25
Monday Night NW 15 - 25
Mt. Rainier Direction - Speed
Sunday Morning --- -
Sunday Afternoon --- -
Sunday Night --- -
Monday Morning --- -
Monday Afternoon --- -
Monday Night --- -
Mt. Hood Direction - Speed
Sunday Morning WSW 35 - 45
Sunday Afternoon WSW 25 - 35
Sunday Night NW 5 - 15
Monday Morning NW 5 - 15
Monday Afternoon NW 10 - 20
Monday Night NW 15 - 25

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 17, 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.