menu

Mountain Weather Forecast

Issued: 7:24 AM PST Sunday, February 26, 2017
by Dennis D'Amico

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.

Weather synopsis for Sunday & Monday

A low pressure system sliding down along the Washington Coast today will rotate showers through mainly the Mt. Hood, south and central Washington Cascades today. As the low slides south, a partial drying and clearing trend will ensue for the northwest Cascades with a mix of sun and clouds likely by the afternoon. While 5-9 inches of low density snow accumulating at Stevens and Snoqualmie Passes respectively overnight, the highest accumulations of new snow forecast during the daylight hours should fall in the southwest Cascades affecting White Pass, Crystal, and Paradise. A light upslope component along the east slopes will allow light snow showers to increase for the southeast and central-east Cascades in the afternoon while the northeast Cascades also partially dry out. There should be a slight rise in snow levels today but overall the air mass will be seasonally cool. As the flow turns light E-NE this afternoon for areas north of the low pressure system, light upslope snow showers should develop and produce a few inches of new snow along the north slopes of the Olympics. 

Showers should taper off overnight as the low fills and the longwave trough axis shifts to the inland NW by early Monday morning. A weaker weather disturbance sliding down in similar fashion along the Washington Coast on Monday in NW flow aloft should increase shower activity for the southwest/central-west Cascades including Mt. Hood in the afternoon. A weak convergence zone oriented may also form in the Snoqualmie Pass area Monday afternoon and evening. With the low snow levels continuing, the lower density snowfall should continue to make the most of out of rather light water amounts. Showers should once again taper off Monday night. 

Weather forecast for Sunday & Monday

Olympics
Date Weather
Sunday

Cloudy with light to occasionally moderate snow showers especially north slopes of the Olympics. 

Sunday Night - Monday Morning

Mostly cloudy with isolated snow showers. 

Monday Afternoon - Monday Evening

Mostly cloudy with scattered light snow showers. 

Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
Date Weather
Sunday Morning

Cloudy with light snow showers north Cascades.  Light to occasionally moderate snow showers south and central Cascades.

Sunday Afternoon - Sunday Evening

Partly sunny north Cascades. Partly to mostly cloudy central Cascades with scattered light snow showers. Cloudy with light to occasionally moderate snow showers south Cascades. 

Sunday Night - Monday Morning

Partly cloudy north Cascades. Mostly cloudy with isolated snow showers south and central Cascades. 

Monday Afternoon - Monday Evening

Mostly cloudy with scattered light snow showers north Cascades. Cloudy with light snow showers central and south Cascades. 

East slopes of the Washington Cascades
Date Weather
Sunday Morning

Cloudy with scattered light snow showers.

Sunday Afternoon - Sunday Evening

Partly sunny northeast Cascades. Cloudy central-east and southeast Cascades with light snow showers. 

Sunday Night - Monday Morning

Partly cloudy northeast Cascades. Mostly cloudy with isolated snow showers southeast and central-east Cascades. 

Monday Afternoon - Monday Evening

Mostly cloudy with scattered light snow showers northeast Cascades. Cloudy with light snow showers central-east and southeast Cascades. 

Mt. Hood Area
Date Weather
Sunday - Sunday Evening

Light to occasionally moderate snow showers.

Sunday Night - Monday Morning

Mostly cloudy with scattered snow showers. 

Monday Afternoon - Monday Evening

Cloudy with light to occasionally moderate snow showers. 

Snow Level/Freezing Level in feet

Date Olympics Northwest Cascades Northeast Cascades Central Cascades South Cascades Easterly Flow in Passes
Sunday Morning Snow Level 1000' 0' 0' 500' 1000' *
Sunday Afternoon Snow Level 1000' 1000' 1000' 1500' 2000' *
Sunday Night - Monday Morning Snow Level 0' 0' 0' 0' 0'
Monday Afternoon Snow Level 500' 0' 500' 1000' 2000'
Olympics
Date Elevation
Sunday Morning Snow Level
1000'
Easterly Flow*
Sunday Afternoon Snow Level
1000'
Easterly Flow*
Sunday Night - Monday Morning Snow Level
0'
Monday Afternoon Snow Level
500'
Monday Night Snow Level
0'
Northwest Cascades
Date Elevation
Sunday Morning Snow Level
0'
Easterly Flow*
Sunday Afternoon Snow Level
1000'
Easterly Flow*
Sunday Night - Monday Morning Snow Level
0'
Monday Afternoon Snow Level
0'
Monday Night Snow Level
0'
Northeast Cascades
Date Elevation
Sunday Morning Snow Level
0'
Easterly Flow*
Sunday Afternoon Snow Level
1000'
Easterly Flow*
Sunday Night - Monday Morning Snow Level
0'
Monday Afternoon Snow Level
500'
Monday Night Snow Level
0'
Central Cascades
Date Elevation
Sunday Morning Snow Level
500'
Easterly Flow*
Sunday Afternoon Snow Level
1500'
Easterly Flow*
Sunday Night - Monday Morning Snow Level
0'
Monday Afternoon Snow Level
1000'
Monday Night Snow Level
0'
South Cascades
Date Elevation
Sunday Morning Snow Level
1000'
Easterly Flow*
Sunday Afternoon Snow Level
2000'
Easterly Flow*
Sunday Night - Monday Morning Snow Level
0'
Monday Afternoon Snow Level
2000'
Monday Night Snow Level
1500'

Cascade Snow / Freezing Levels noted above refer to the north (approximately Mt Baker and Washington Pass), central (approximately Stevens to White Pass) and south (near Mt Hood). Freezing Level is when no precipitation is forecast.
* Note that surface snow levels are common near the passes during easterly pass flow and may result in multiple snow / freezing levels.

24 Hour Quantitative Precipitation ending at 4 am

Location Mon Tue
Hurricane Ridge .25 - .50 lt .10
Mt Baker Ski Area lt .25 lt .10
Washington Pass lt .25 lt .10
Stevens Pass .25 lt .10
Snoqualmie Pass .25 - .50 lt .25
Mission Ridge lt .25 lt .10
Crystal Mt .50 lt .25
Paradise .75 lt .25
White Pass .50 lt .25
Mt Hood Meadows .50 - .75 .50 - .75

Winds in Miles per Hour (MPH) "Cascade Pass Level Winds"

Date Direction - Speed
Sunday E 10 - 20
Sunday Night - Monday Morning E 5 - 15

Directions above indicate the direction the wind blows from on the 16-point cardinal scale. Winds near the passes tend to be highly channeled by the topography and normally blow either easterly or westerly depending on the surface pressure gradients that drive such winds.

Free Winds at 5000' (in Miles per Hour (MPH))

Date Olympics Northwest Cascades Central Cascades South Cascades
Sunday Morning SE 0 - 10 SE 0 - 10 SW 10 - 20 SW 10 - 20
Sunday Afternoon ENE 10 - 20 NE 5 - 15 E 5 - 15 SW 5 - 15
Sunday Night - Monday Morning W 0 - 10 E 0 - 10 W 0 - 10 WSW 0 - 10
Monday Afternoon VAR 0 - 10 W 0 - 10 WSW 5 - 15 W 10 - 20
Olympics
Date Elevation
Sunday Morning SE 0 - 10
Sunday Afternoon ENE 10 - 20
Sunday Night - Monday Morning W 0 - 10
Monday Afternoon VAR 0 - 10
Monday Night W 5 - 15
Northwest Cascades
Date Elevation
Sunday Morning SE 0 - 10
Sunday Afternoon NE 5 - 15
Sunday Night - Monday Morning E 0 - 10
Monday Afternoon W 0 - 10
Monday Night W 0 - 10
Central Cascades
Date Elevation
Sunday Morning SW 10 - 20
Sunday Afternoon E 5 - 15
Sunday Night - Monday Morning W 0 - 10
Monday Afternoon WSW 5 - 15
Monday Night WSW 5 - 15
South Cascades
Date Elevation
Sunday Morning SW 10 - 20
Sunday Afternoon SW 5 - 15
Sunday Night - Monday Morning WSW 0 - 10
Monday Afternoon W 10 - 20
Monday Night W 15 - 30
Olympics
Date Direction - Speed
Sunday Morning SE 0 - 10
Sunday Afternoon ENE 10 - 20
Sunday Night - Monday Morning W 0 - 10
Monday Afternoon VAR 0 - 10
Monday Night W 5 - 15
Northwest Cascades
Date Direction - Speed
Sunday Morning SE 0 - 10
Sunday Afternoon NE 5 - 15
Sunday Night - Monday Morning E 0 - 10
Monday Afternoon W 0 - 10
Monday Night W 0 - 10
Central Cascades
Date Direction - Speed
Sunday Morning SW 10 - 20
Sunday Afternoon E 5 - 15
Sunday Night - Monday Morning W 0 - 10
Monday Afternoon WSW 5 - 15
Monday Night WSW 5 - 15
South Cascades
Date Direction - Speed
Sunday Morning SW 10 - 20
Sunday Afternoon SW 5 - 15
Sunday Night - Monday Morning WSW 0 - 10
Monday Afternoon W 10 - 20
Monday Night W 15 - 30

Directions above indicate the direction the wind blows from on the 16-point cardinal scale. These winds and the 9000 ft winds below also 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' (in Miles per Hour (MPH))

Date Northwest Cascades Northeast Cascades Central Cascades South Cascades
Sunday Morning SW 5 - 15 WSW 0 - 10 WSW 15 - 25 W 25 - 40
Sunday Afternoon E 5 - 15 NE 5 - 15 SE 5 - 15 W 15 - 25
Sunday Night - Monday Morning W 10 - 20 W 10 - 20 WNW 10 - 20 W 10 - 20
Northwest Cascades
Date Direction - Speed
Sunday Morning SW 5 - 15
Sunday Afternoon E 5 - 15
Sunday Night - Monday Morning W 10 - 20
Monday Afternoon - Monday Night W 10 - 20
Northeast Cascades
Date Direction - Speed
Sunday Morning WSW 0 - 10
Sunday Afternoon NE 5 - 15
Sunday Night - Monday Morning W 10 - 20
Monday Afternoon - Monday Night W 5 - 15
Central Cascades
Date Direction - Speed
Sunday Morning WSW 15 - 25
Sunday Afternoon SE 5 - 15
Sunday Night - Monday Morning WNW 10 - 20
Monday Afternoon - Monday Night W 15 - 25
South Cascades
Date Direction - Speed
Sunday Morning W 25 - 40
Sunday Afternoon W 15 - 25
Sunday Night - Monday Morning W 10 - 20
Monday Afternoon - Monday Night W 20 - 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.

The Extended Mountain Weather Forecast (Days 3-5) will be included with the afternoon forecast issuance around 1:30 PM.