menu

Mountain Weather Forecast

Issued: 2:34 PM PST Monday, January 1, 2018
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 Monday & Tuesday

Happy New Year!  We have a quiet weather pattern to ring in 2018 with upper ridging offshore and light to moderate offshore flow at the surface. Freezing levels will be mild over the short term period with cooler temperatures seen along the east slopes of the Cascades and in the Cascades Passes. A strong inversion Monday afternoon has temperatures in the teens at the base of Stevens Pass while temperatures at the top of the ski area are near 40.  

A weak front dissipating over Vancouver Island should bring some periods of high clouds today. Low clouds should hang tough along the east slopes of the Cascades and lower slopes of the Cascade Passes throughout the short term. A weak upper level disturbance cutting through the upper level ridge on Tuesday will not bring any precipitation but will produce some high/mid level cloudiness over the region. 

Weather forecast for Monday & Tuesday

Olympics
Date Weather
Monday Mostly sunny and mild with periods of high clouds.
Monday Night Partly cloudy and mild with periods of high clouds.
Tuesday Mostly cloudy. Mild.
Mostly cloudy. Mild.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Date Weather
Monday Mostly sunny with periods of high clouds west of the crest. Lower clouds and cooler temperatures Cascade Passes.
Monday Night Partly cloudy with periods of high clouds west of the crest. Lower clouds and cooler temperatures Cascade Passes.
Tuesday Mostly cloudy. Cooler and cloudier Cascade Passes.
Mostly cloudy. Cooler and cloudier Cascade Passes.
East Slopes of the Washington Cascades
Date Weather
Monday Partly sunny with periods of high clouds, low clouds lower slopes.
Monday Night Partly cloudy with periods of high clouds, low clouds lower slopes.
Tuesday Mostly cloudy. Cooler and cloudier lower slopes.
Mostly cloudy. Cooler and cloudier lower slopes.
Mt. Hood
Date Weather
Monday Partly sunny with periods of high clouds.
Monday Night Partly cloudy with periods of high clouds. Cooler and cloudier lower elevations exposed to easterly flow.
Tuesday Mostly cloudy. Cooler and cloudier lower elevations exposed to easterly flow.
Mostly cloudy.

Snow Level/Freezing Level in feet

Date Olympics Northwest Cascades Northeast Cascades Central Cascades South Cascades Easterly Flow in Passes
Monday Afternoon Freezing Level 9000' 8000' 5000' 8000' 10000' *
Monday Night Freezing Level 9500' 8000' 3000' 8500' 10000' *
Tuesday Freezing Level 9500' 8500' 7500' 9000' 10500' *
Olympics
Date Elevation
Monday Afternoon Freezing Level
9000'
Easterly Flow*
Monday Night Freezing Level
9500'
Easterly Flow*
Tuesday Freezing Level
9500'
Easterly Flow*
Tuesday Night Freezing Level
9500'
Easterly Flow*
Northwest Cascades
Date Elevation
Monday Afternoon Freezing Level
8000'
Easterly Flow*
Monday Night Freezing Level
8000'
Easterly Flow*
Tuesday Freezing Level
8500'
Easterly Flow*
Tuesday Night Freezing Level
8500'
Easterly Flow*
Northeast Cascades
Date Elevation
Monday Afternoon Freezing Level
5000'
Easterly Flow*
Monday Night Freezing Level
3000'
Easterly Flow*
Tuesday Freezing Level
7500'
Easterly Flow*
Tuesday Night Freezing Level
7500'
Easterly Flow*
Central Cascades
Date Elevation
Monday Afternoon Freezing Level
8000'
Easterly Flow*
Monday Night Freezing Level
8500'
Easterly Flow*
Tuesday Freezing Level
9000'
Easterly Flow*
Tuesday Night Freezing Level
9000'
Easterly Flow*
South Cascades
Date Elevation
Monday Afternoon Freezing Level
10000'
Easterly Flow*
Monday Night Freezing Level
10000'
Easterly Flow*
Tuesday Freezing Level
10500'
Easterly Flow*
Tuesday Night Freezing Level
10500'
Easterly Flow*

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 Tue Wed
Hurricane Ridge 0 0
Mt Baker Ski Area 0 0
Washington Pass 0 0
Stevens Pass 0 0
Snoqualmie Pass 0 0
Mission Ridge 0 0
Crystal Mt 0 0
Paradise 0 0
White Pass 0 0
Mt Hood Meadows 0 0

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

Date Direction - Speed
Monday E 15 - 25
Monday Night E 15 - 25
Tuesday E 20 - 30

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
Monday Afternoon VAR 0 - 10 VAR 0 - 10 VAR 0 - 10 E 0 - 10
Monday Night SE 0 - 10 ESE 0 - 10 E 0 - 10 ESE 0 - 10
Tuesday S 0 - 10 ENE 0 - 10 ESE 10 - 20 ESE 10 - 20
Olympics
Date Elevation
Monday Afternoon VAR 0 - 10
Monday Night SE 0 - 10
Tuesday S 0 - 10
Tuesday Night SE 0 - 10
Northwest Cascades
Date Elevation
Monday Afternoon VAR 0 - 10
Monday Night ESE 0 - 10
Tuesday ENE 0 - 10
Tuesday Night VAR 0 - 10
Central Cascades
Date Elevation
Monday Afternoon VAR 0 - 10
Monday Night E 0 - 10
Tuesday ESE 10 - 20
Tuesday Night E 0 - 10
South Cascades
Date Elevation
Monday Afternoon E 0 - 10
Monday Night ESE 0 - 10
Tuesday ESE 10 - 20
Tuesday Night ESE 0 - 10
Olympics
Date Direction - Speed
Monday Afternoon VAR 0 - 10
Monday Night SE 0 - 10
Tuesday S 0 - 10
Tuesday Night SE 0 - 10
Northwest Cascades
Date Direction - Speed
Monday Afternoon VAR 0 - 10
Monday Night ESE 0 - 10
Tuesday ENE 0 - 10
Tuesday Night VAR 0 - 10
Central Cascades
Date Direction - Speed
Monday Afternoon VAR 0 - 10
Monday Night E 0 - 10
Tuesday ESE 10 - 20
Tuesday Night E 0 - 10
South Cascades
Date Direction - Speed
Monday Afternoon E 0 - 10
Monday Night ESE 0 - 10
Tuesday ESE 10 - 20
Tuesday Night ESE 0 - 10

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
Monday Afternoon NW 10 - 20 NW 5 - 15 NW 10 - 20 NW 5 - 15
Monday Night SW 0 - 10 SW 0 - 10 SW 0 - 10 SW 5 - 15
Tuesday Morning SW 0 - 10 S 5 - 15 S 0 - 10 S 10 - 20
Tuesday Afternoon SW 5 - 15 SW 5 - 15 SW 10 - 20 SW 10 - 20
Northwest Cascades
Date Direction - Speed
Monday Afternoon NW 10 - 20
Monday Night SW 0 - 10
Tuesday Morning SW 0 - 10
Tuesday Afternoon SW 5 - 15
Tuesday Night W 0 - 10
Northeast Cascades
Date Direction - Speed
Monday Afternoon NW 5 - 15
Monday Night SW 0 - 10
Tuesday Morning S 5 - 15
Tuesday Afternoon SW 5 - 15
Tuesday Night W 0 - 10
Central Cascades
Date Direction - Speed
Monday Afternoon NW 10 - 20
Monday Night SW 0 - 10
Tuesday Morning S 0 - 10
Tuesday Afternoon SW 10 - 20
Tuesday Night WSW 10 - 20
South Cascades
Date Direction - Speed
Monday Afternoon NW 5 - 15
Monday Night SW 5 - 15
Tuesday Morning S 10 - 20
Tuesday Afternoon SW 10 - 20
Tuesday Night SW 10 - 20

Extended Weather Synopsis for Wednesday through Friday

The upper level ridge will shift inland on Wednesday. Freezing levels will continue to be on the mild side but a fair amount of cloud cover will once again sneak under the ridge from a cut-off low off the California coast.  That upper low will weaken and eject northward over our area on Thursday. There's a slight chance of showers reaching the Olympics or Mt. Hood by the afternoon, but most areas will likely just see an increase in cloud cover as the day progresses.  An upper low complex will meander closer to the Washington/Oregon coast on Friday, increasing the likelihood of showers. Forecast models are not in good agreement on timing or intensity for Friday's system.  Snow levels will lower slightly toward the end of the work week. 

Extended Weather Forecast for Wednesday through Friday

Olympics, Washington Cascades and Mt. Hood Area
Date Weather
Wednesday Fair with partly to mostly cloudy skies.
Thursday Mostly cloudy with a slight chance of rain or snow showers late in the day. Cloudy with a chance of rain or snow showers overnight.

Snow/Freezing Levels

Date Olympics Northwest Cascades Northeast Cascades Central Cascades South Cascades Easterly Flow in Passes
Wednesday Freezing Level 8500' - 9500' 8000' - 9000' 7500' - 8500' 8500' - 9500' 9500' - 10500' *
Wednesday Night Freezing Level 8500' - 9500' 8000' - 9000' 8000' - 9000' 8500' - 9500' 8500' - 9500' *
Thursday Freezing Level 7500' - 8500' 7500' - 8500' 8000' - 9000' 7500' - 8500' 7500' - 8500' *
Thursday Night Snow Level 6000' - 7000' 6000' - 7000' 4000' - 5000' 5500' - 6500' 6500' - 7500' *
Olympics
Date Elevation
Wednesday Freezing Level
8500' - 9500'
Easterly Flow*
Wednesday Night Freezing Level
8500' - 9500'
Easterly Flow*
Thursday Freezing Level
7500' - 8500'
Easterly Flow*
Thursday Night Snow Level
6000' - 7000'
Easterly Flow*
Friday Snow Level
5000' - 6000'
Northwest Cascades
Date Elevation
Wednesday Freezing Level
8000' - 9000'
Easterly Flow*
Wednesday Night Freezing Level
8000' - 9000'
Easterly Flow*
Thursday Freezing Level
7500' - 8500'
Easterly Flow*
Thursday Night Snow Level
6000' - 7000'
Easterly Flow*
Friday Snow Level
4000' - 5000'
Northeast Cascades
Date Elevation
Wednesday Freezing Level
7500' - 8500'
Easterly Flow*
Wednesday Night Freezing Level
8000' - 9000'
Easterly Flow*
Thursday Freezing Level
8000' - 9000'
Easterly Flow*
Thursday Night Snow Level
4000' - 5000'
Easterly Flow*
Friday Snow Level
4000' - 5000'
Central Cascades
Date Elevation
Wednesday Freezing Level
8500' - 9500'
Easterly Flow*
Wednesday Night Freezing Level
8500' - 9500'
Easterly Flow*
Thursday Freezing Level
7500' - 8500'
Easterly Flow*
Thursday Night Snow Level
5500' - 6500'
Easterly Flow*
Friday Snow Level
4500' - 5500'
South Cascades
Date Elevation
Wednesday Freezing Level
9500' - 10500'
Easterly Flow*
Wednesday Night Freezing Level
8500' - 9500'
Easterly Flow*
Thursday Freezing Level
7500' - 8500'
Easterly Flow*
Thursday Night Snow Level
6500' - 7500'
Easterly Flow*
Friday Snow Level
4500' - 5500'

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.