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Mountain Weather Forecast

Issued: 9:11 AM PST Saturday, April 22, 2017
by Kenny Kramer

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 Saturday & Sunday

The upper level ridge of high pressure that allowed for a warm, beautiful day Friday has moved east across Idaho by early Saturday. Temperatures remained very mild overnight and early Saturday with many NWAC stations in the lower 40's. A return to an active weather pattern in the PNW for this coming week is underway. 

An upper trough has developed well offshore and extends from about Astoria, OR northwestward well off the WA coast early Saturday. A band of precipitation is rotating northward across the northern OR coast Saturday morning and should lift northward across the forecast area through the afternoon and evening.

The upper trough will be more east to west oriented as it brings the moisture band across the area later Saturday and that will mean it will not be particularly strong, lacking upper level support.

A period of generally light to briefly moderate precipitation will change to light showers by Saturday afternoon and evening, before tapering or ending overnight.

A brief break in precipitation is expected later Saturday night through early Sunday before the next wave arrives midday and through Sunday afternoon. The upper level trough will remain offshore, maintaining unsettled and cooler conditions with periods of showers or steady precipitation at times heading into next week.

Weather forecast for Saturday & Sunday

Olympics
Date Weather
Saturday

Light to occasionally moderate rain and snow developing late-morning and becoming light rain and snow showers in the afternoon. 

Saturday Night - Sunday Morning

Mostly cloudy with light rain and snow showers tapering or ending overnight through early Sunday. 

Renewed light to occasionally moderate rain and snow showers. Showers diminishing overnight.

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

Light rain and snow developing late morning and becoming light to occasionally moderate in the afternoon. A few sunbreaks possible in the southwest Cascades in the afternoon. 

Saturday Night - Sunday Morning

Mostly cloudy with light rain and snow showers tapering or ending overnight through early Sunday, except occasionally light to moderate showers persisting in the Mt. Baker area. 

Renewed light to occasionally moderate rain and snow showers. Showers diminishing overnight.

East slopes of the Washington Cascades
Date Weather
Saturday - Saturday Evening

Cloudy with light rain and snow developing late morning, then becoming mostly cloudy with scattered light rain and snow showers in the late afternoon and evening.

 

Saturday Night - Sunday Morning

Partly to mostly cloudy with isolated light rain and snow showers ending in the evening through early Sunday.  

Renewed light rain and snow showers. Showers diminishing overnight.

Mt. Hood Area
Date Weather
Saturday

Very light rain and snow developing in the morning and becoming mostly cloudy with scattered light rain and snow showers in the afternoon. 

Saturday Night

Mostly cloudy with isolated light rain and snow showers in the evening ending overnight and becoming partly cloudy. 

Renewed light to moderate rain and snow showers Sunday morning through Sunday afternoon. Showers diminishing overnight.

Snow Level/Freezing Level in feet

Date Olympics Northwest Cascades Northeast Cascades Central Cascades South Cascades Easterly Flow in Passes
Saturday Snow Level 5500' 5500' 5500' 5500' 6000' *
Saturday Night Snow Level 4000' 4000' 4000' 4000' 4500'
Sunday Snow Level 4000' 4500' 4500' 4500' 5000'
Olympics
Date Elevation
Saturday Snow Level
5500'
Easterly Flow*
Saturday Night Snow Level
4000'
Sunday Snow Level
4000'
Sunday Night Snow Level
3500'
Northwest Cascades
Date Elevation
Saturday Snow Level
5500'
Easterly Flow*
Saturday Night Snow Level
4000'
Sunday Snow Level
4500'
Sunday Night Snow Level
3000'
Northeast Cascades
Date Elevation
Saturday Snow Level
5500'
Easterly Flow*
Saturday Night Snow Level
4000'
Sunday Snow Level
4500'
Sunday Night Snow Level
3000'
Central Cascades
Date Elevation
Saturday Snow Level
5500'
Easterly Flow*
Saturday Night Snow Level
4000'
Sunday Snow Level
4500'
Sunday Night Snow Level
3500'
South Cascades
Date Elevation
Saturday Snow Level
6000'
Easterly Flow*
Saturday Night Snow Level
4500'
Sunday Snow Level
5000'
Sunday Night Snow Level
4000'

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 Sun Mon
Hurricane Ridge .25 .25
Mt Baker Ski Area .50 .75
Washington Pass lt .25 lt .25
Stevens Pass .25 .25 - .50
Snoqualmie Pass .25 .50
Mission Ridge lt .10 lt .25
Crystal Mt .25 .25 - .50
Paradise .25 .75 - 1.00
White Pass lt .25 .25 - .50
Mt Hood Meadows lt .25 .75

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

Date Direction - Speed
Saturday Morning E 15 - 30
Saturday Afternoon W 10 - 15
Saturday Night - Sunday W 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
Saturday Morning SE 10 - 20 E 5 - 15 ESE 20 - 35 SSE 15 - 30
Saturday Afternoon SSW 15 - 25 S 15 - 25 SW 15 - 25 SW 15 - 25
Saturday Night - Sunday Morning SW 0 - 10 S 5 - 15 SW 0 - 10 WSW 5 - 15
Olympics
Date Elevation
Saturday Morning SE 10 - 20
Saturday Afternoon SSW 15 - 25
Saturday Night - Sunday Morning SW 0 - 10
Sunday Afternoon - Sunday Night SW 5 - 15
Northwest Cascades
Date Elevation
Saturday Morning E 5 - 15
Saturday Afternoon S 15 - 25
Saturday Night - Sunday Morning S 5 - 15
Sunday Afternoon - Sunday Night SW 5 - 15
Central Cascades
Date Elevation
Saturday Morning ESE 20 - 35
Saturday Afternoon SW 15 - 25
Saturday Night - Sunday Morning SW 0 - 10
Sunday Afternoon - Sunday Night SW 10 - 20
South Cascades
Date Elevation
Saturday Morning SSE 15 - 30
Saturday Afternoon SW 15 - 25
Saturday Night - Sunday Morning WSW 5 - 15
Sunday Afternoon - Sunday Night SW 10 - 20
Olympics
Date Direction - Speed
Saturday Morning SE 10 - 20
Saturday Afternoon SSW 15 - 25
Saturday Night - Sunday Morning SW 0 - 10
Sunday Afternoon - Sunday Night SW 5 - 15
Northwest Cascades
Date Direction - Speed
Saturday Morning E 5 - 15
Saturday Afternoon S 15 - 25
Saturday Night - Sunday Morning S 5 - 15
Sunday Afternoon - Sunday Night SW 5 - 15
Central Cascades
Date Direction - Speed
Saturday Morning ESE 20 - 35
Saturday Afternoon SW 15 - 25
Saturday Night - Sunday Morning SW 0 - 10
Sunday Afternoon - Sunday Night SW 10 - 20
South Cascades
Date Direction - Speed
Saturday Morning SSE 15 - 30
Saturday Afternoon SW 15 - 25
Saturday Night - Sunday Morning WSW 5 - 15
Sunday Afternoon - Sunday Night SW 10 - 20

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
Saturday Morning S 10 - 20 S 15 - 25 S 20 - 30 SSW 20 - 30
Saturday Afternoon SW 25 - 35 SW 15 - 25 SW 20 - 30 SW 25 - 35
Saturday Night - Sunday Morning SW 5 - 15 WSW 5 - 15 WSW 10 - 20 SW 20 - 30
Northwest Cascades
Date Direction - Speed
Saturday Morning S 10 - 20
Saturday Afternoon SW 25 - 35
Saturday Night - Sunday Morning SW 5 - 15
Sunday Afternoon - Sunday Night SW 10 - 20
Northeast Cascades
Date Direction - Speed
Saturday Morning S 15 - 25
Saturday Afternoon SW 15 - 25
Saturday Night - Sunday Morning WSW 5 - 15
Sunday Afternoon - Sunday Night SW 10 - 20
Central Cascades
Date Direction - Speed
Saturday Morning S 20 - 30
Saturday Afternoon SW 20 - 30
Saturday Night - Sunday Morning WSW 10 - 20
Sunday Afternoon - Sunday Night SW 20 - 30
South Cascades
Date Direction - Speed
Saturday Morning SSW 20 - 30
Saturday Afternoon SW 25 - 35
Saturday Night - Sunday Morning SW 20 - 30
Sunday Afternoon - Sunday Night SW 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.

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