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Mountain Weather Forecast

Issued: 2:51 PM PST Friday, January 19, 2018
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 Friday & Saturday

A relatively slow moving and gradually weakening low pressure system is nearing the British Columbia coast Friday afternoon.  With the low pressure system reluctant to move, the resultant cool showery weather pattern over the PNW will persist through Saturday night.

Bands of active showers continue to rotate around the low, causing light to occasionally moderate showers at relatively low snow levels over most areas. The Mt Baker and Hurricane Ridge areas in the Olympics have received the greatest recent snowfall in this pattern.

Crest level winds continue to be moderate and generally from the SW.

The associated upper trough axis will move across the area overnight Friday to cause a period of enhanced moderate snow showers over most areas. The favored areas remain the volcanic peaks and especially the Mt Baker area. 

Showers should diminish on Saturday as a shallow high pressure ridge passes the area. Though scattered light showers will persist. 

A stronger frontal system should approach the coast Saturday night bringing renewed light to moderate precipitation and increasing winds, initially to the Olympics and Mt Baker area late Saturday night.

Weather forecast for Friday & Saturday

Olympics
Date Weather
Friday Afternoon Scattered light snow showers.
Friday Night Increasing light to moderate snow showers.
Saturday Scattered light snow showers.
Light snow showers with steady light to moderate rain and snow developing late night.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Date Weather
Friday Afternoon Mostly light snow showers. Light to occasional moderate showers over the volcanoes.
Friday Night Increasing light to moderate snow showers all areas.
Saturday Mostly light snow showers.
Light snow showers. Increasing steady light to moderate snow vicinity of Mt Baker and north part late night and early Sunday..
East Slopes of the Washington Cascades
Date Weather
Friday Afternoon Partly to mostly cloudy with light snow showers.
Friday Night Increasing light to moderate snow showers.
Saturday Partly to mostly cloudy with scattered light snow showers.
Scattered light snow showers.
Mt. Hood
Date Weather
Friday Afternoon Light snow showers.
Friday Night Increasing light to moderate snow showers.
Saturday Light snow showers.
Scattered light snow showers.

Snow Level/Freezing Level in feet

Date Olympics Northwest Cascades Northeast Cascades Central Cascades South Cascades Easterly Flow in Passes
Friday Afternoon Snow Level 2500' 2500' 2000' 3000' 3000'
Friday Night Snow Level 2000' 2000' 1500' 2000' 2500'
Saturday Morning Snow Level 2000' 2000' 1500' 2000' 2000'
Saturday Afternoon Snow Level 2500' 2000' 2000' 2500' 2500'
Olympics
Date Elevation
Friday Afternoon Snow Level
2500'
Friday Night Snow Level
2000'
Saturday Morning Snow Level
2000'
Saturday Afternoon Snow Level
2500'
Saturday Night Snow Level
2500'
Easterly Flow*
Northwest Cascades
Date Elevation
Friday Afternoon Snow Level
2500'
Friday Night Snow Level
2000'
Saturday Morning Snow Level
2000'
Saturday Afternoon Snow Level
2000'
Saturday Night Snow Level
2500'
Easterly Flow*
Northeast Cascades
Date Elevation
Friday Afternoon Snow Level
2000'
Friday Night Snow Level
1500'
Saturday Morning Snow Level
1500'
Saturday Afternoon Snow Level
2000'
Saturday Night Snow Level
1500'
Easterly Flow*
Central Cascades
Date Elevation
Friday Afternoon Snow Level
3000'
Friday Night Snow Level
2000'
Saturday Morning Snow Level
2000'
Saturday Afternoon Snow Level
2500'
Saturday Night Snow Level
2500'
Easterly Flow*
South Cascades
Date Elevation
Friday Afternoon Snow Level
3000'
Friday Night Snow Level
2500'
Saturday Morning Snow Level
2000'
Saturday Afternoon Snow Level
2500'
Saturday Night Snow Level
3000'
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 Sat Sun
Hurricane Ridge .25 .25 - .50
Mt Baker Ski Area .75 .50
Washington Pass .25 lt .25
Stevens Pass .25 .25
Snoqualmie Pass .25 .25
Mission Ridge lt .10 lt .10
Crystal Mt lt .25 lt .25
Paradise .50 .25 - .50
White Pass .25 lt .25
Mt Hood Meadows .25 - .50 .25 - .50

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

Date Direction - Speed
Friday Afternoon W 5 - 15
Friday Night VAR 0 - 10
Saturday Morning VAR 0 - 10
Saturday Afternoon VAR 0 - 10

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
Friday Afternoon SSW 15 - 25 SSW 15 - 25 SSW 15 - 25 SW 10 - 20
Friday Night WSW 20 - 30 SW 15 - 25 WSW 15 - 25 SW 10 - 20
Saturday Morning WSW 20 - 30 SW 15 - 25 WSW 15 - 25 WSW 15 - 25
Saturday Afternoon SW 25 - 35 SSW 15 - 25 SW 20 - 30 WSW 20 - 30
Olympics
Date Elevation
Friday Afternoon SSW 15 - 25
Friday Night WSW 20 - 30
Saturday Morning WSW 20 - 30
Saturday Afternoon SW 25 - 35
Saturday Night SSW 40 - 60
Northwest Cascades
Date Elevation
Friday Afternoon SSW 15 - 25
Friday Night SW 15 - 25
Saturday Morning SW 15 - 25
Saturday Afternoon SSW 15 - 25
Saturday Night SSW 30 - 40
Central Cascades
Date Elevation
Friday Afternoon SSW 15 - 25
Friday Night WSW 15 - 25
Saturday Morning WSW 15 - 25
Saturday Afternoon SW 20 - 30
Saturday Night SSW 30 - 40
South Cascades
Date Elevation
Friday Afternoon SW 10 - 20
Friday Night SW 10 - 20
Saturday Morning WSW 15 - 25
Saturday Afternoon WSW 20 - 30
Saturday Night SSW 30 - 40
Olympics
Date Direction - Speed
Friday Afternoon SSW 15 - 25
Friday Night WSW 20 - 30
Saturday Morning WSW 20 - 30
Saturday Afternoon SW 25 - 35
Saturday Night SSW 40 - 60
Northwest Cascades
Date Direction - Speed
Friday Afternoon SSW 15 - 25
Friday Night SW 15 - 25
Saturday Morning SW 15 - 25
Saturday Afternoon SSW 15 - 25
Saturday Night SSW 30 - 40
Central Cascades
Date Direction - Speed
Friday Afternoon SSW 15 - 25
Friday Night WSW 15 - 25
Saturday Morning WSW 15 - 25
Saturday Afternoon SW 20 - 30
Saturday Night SSW 30 - 40
South Cascades
Date Direction - Speed
Friday Afternoon SW 10 - 20
Friday Night SW 10 - 20
Saturday Morning WSW 15 - 25
Saturday Afternoon WSW 20 - 30
Saturday Night SSW 30 - 40

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
Friday Afternoon SW 15 - 25 SW 20 - 30 SW 25 - 35 SW 20 - 30
Friday Night WSW 25 - 35 WSW 20 - 30 WSW 25 - 35 WSW 20 - 30
Saturday Morning WSW 20 - 30 WSW 25 - 35 WSW 25 - 35 WSW 20 - 30
Saturday Afternoon SW 20 - 30 WSW 25 - 35 WSW 25 - 35 WSW 20 - 30
Northwest Cascades
Date Direction - Speed
Friday Afternoon SW 15 - 25
Friday Night WSW 25 - 35
Saturday Morning WSW 20 - 30
Saturday Afternoon SW 20 - 30
Saturday Night SSW 40 - 60
Northeast Cascades
Date Direction - Speed
Friday Afternoon SW 20 - 30
Friday Night WSW 20 - 30
Saturday Morning WSW 25 - 35
Saturday Afternoon WSW 25 - 35
Saturday Night SSW 35 - 50
Central Cascades
Date Direction - Speed
Friday Afternoon SW 25 - 35
Friday Night WSW 25 - 35
Saturday Morning WSW 25 - 35
Saturday Afternoon WSW 25 - 35
Saturday Night SSW 35 - 50
South Cascades
Date Direction - Speed
Friday Afternoon SW 20 - 30
Friday Night WSW 20 - 30
Saturday Morning WSW 20 - 30
Saturday Afternoon WSW 20 - 30
Saturday Night SW 30 - 40

Extended Weather Synopsis for Sunday through Tuesday

A strong north to south oriented front should be moving inland across the region Sunday morning. This will cause increasing moderate to heavy precipitation and very strong crest level winds Sunday. The flow pattern will again favor the volcanoes.

Only a brief and shallow warming is anticipated Sunday before cooling occurs behind the frontal passage.

A cool showery pattern should follow the frontal passage Sunday night. 

Cool and moist westerly flow will maintain generally light showers Monday and Tuesday. This should favor the west slopes of the WA Cascades and volcanoes, however showers overall should remain light.  

Extended Weather Forecast for Sunday through Tuesday

Olympics, Washington Cascades and Mt. Hood Area
Date Weather
Sunday Increasing moderate to heavy rain and snow and becoming stormy midday. Rain and snow changing to showers late Sunday or Sunday night. Heaviest precipitation over the volcanoes.
Monday Light to occasional moderate showers. Showers, mainly west slopes WA Cascades and volcanoes.

Snow/Freezing Levels

Date Olympics Northwest Cascades Northeast Cascades Central Cascades South Cascades Easterly Flow in Passes
Sunday Snow Level 2500' - 3500' 2000' - 3000' 2000' - 3000' 2000' - 3500' 3000' - 4000'
Sunday Night Snow Level 2500' - 3500' 2000' - 3000' 1500' - 2500' 2000' - 3500' 3000' - 4000'
Monday Snow Level 2000' - 3000' 2000' - 3000' 2000' - 3000' 2000' - 3000' 2000' - 3000'
Monday Night Snow Level 2000' - 3000' 1500' - 2500' 1000' - 2000' 2000' - 3000' 2500' - 3500'
Olympics
Date Elevation
Sunday Snow Level
2500' - 3500'
Sunday Night Snow Level
2500' - 3500'
Monday Snow Level
2000' - 3000'
Monday Night Snow Level
2000' - 3000'
Tuesday Snow Level
2000' - 3000'
Northwest Cascades
Date Elevation
Sunday Snow Level
2000' - 3000'
Sunday Night Snow Level
2000' - 3000'
Monday Snow Level
2000' - 3000'
Monday Night Snow Level
1500' - 2500'
Tuesday Snow Level
1500' - 2500'
Northeast Cascades
Date Elevation
Sunday Snow Level
2000' - 3000'
Sunday Night Snow Level
1500' - 2500'
Monday Snow Level
2000' - 3000'
Monday Night Snow Level
1000' - 2000'
Tuesday Snow Level
1000' - 2000'
Central Cascades
Date Elevation
Sunday Snow Level
2000' - 3500'
Sunday Night Snow Level
2000' - 3500'
Monday Snow Level
2000' - 3000'
Monday Night Snow Level
2000' - 3000'
Tuesday Snow Level
2000' - 3000'
South Cascades
Date Elevation
Sunday Snow Level
3000' - 4000'
Sunday Night Snow Level
3000' - 4000'
Monday Snow Level
2000' - 3000'
Monday Night Snow Level
2500' - 3500'
Tuesday Snow Level
2500' - 3500'

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.