Issued: 7:34 AM PST Wednesday, December 16, 2015
by Dennis D'Amico

Jump to: Weather Forecast I Snow/Freezing Level I Precipitation I Free Winds 5k I Free Winds 9k I Extended Weather

Weather Synopsis for Wednesday & Saturday

A weak shortwave that passed through in NW flow aloft produced a few inches (up to 7 inches at Stevens Pass) of snow overnight and early Wednesday morning along the west slopes of the Cascades. Scattered showers will continue mainly along the west slopes, Mt. Hood and the north slopes of the Olympics through mid-day with sunnier skies along the east slopes. 

The next incoming Pacific frontal system will be more powerful. Mid and high clouds will spread over the PNW tonight with moderate snow developing for Mt. Hood early Friday morning.  The heaviest precipitation should be for the south Washington Cascades and Mt. Hood area. Warm air will work it's way into the Mt. Hood area and the Olympics, causing a switch to rain at lower and mid-elevations. The Crystal/Paradise area should briefly rise to around 5000 feet Thursday afternoon and evening, but areas further north should remain cooler. 

As a secondary wave pushes the frontal boundary through Thursday night, heavier precipitation should spread further north. 

Weather Forecast

Olympics, Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
Wednesday Morning

Mostly cloudy with scattered light showers along the west slopes of the Cascades and the north slopes of the Olympics. 

Wednesday Afternoon - Wednesday Night

Partly cloudy with isolated showers.  Increasing high clouds overnight with light snow developing late overnight Olympics and south Washington Cascades. 

Thursday

Light snow in the north Cascades and Olympics and moderate rain and snow in the central and south Washington Cascades. Warming trend Olympics and far south Washington Cascades. 

East slopes of the Washington Cascades
Wednesday Morning

Partly cloudy with scattered light showers near the Cascade crest.  

Wednesday Afternoon - Wednesday Night

Mostly clear.  

Thursday

Light snow in the northeast Cascades and light to moderate snow in the central and southeast Washington Cascades. 

Mt. Hood Area
Wednesday

Mostly cloudy with scattered light showers in the morning.  Partly cloudy with isolated showers in the afternoon. 

Wednesday Afternoon - Wednesday Night

Increasing high clouds Wednesday evening with moderate rain and snow developing overnight. 

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Wednesday - Wednesday Night Snow Level 2500' 1000' 0' ' ' 2000' ' 3000'
Thursday Morning Snow Level * 3500' 1500' 500' ' ' 1000' ' 3000'
Thursday Mid-day Snow Level * 4500' 2000' 1000' ' ' 1500' ' 4500'
Thursday Afternoon Snow Level * 6500' 2500' 1000' ' ' 2500' ' 7000'
Hurricane Ridge Elevation
Wednesday - Wednesday Night Snow Level
2500'
Thursday Morning Snow Level
3500'
(Easterly Flow *)
Thursday Mid-day Snow Level
4500'
(Easterly Flow *)
Thursday Afternoon Snow Level
6500'
(Easterly Flow *)
Thursday Night Snow Level
6500'
(Easterly Flow *)
Mt. Baker Elevation
Wednesday - Wednesday Night Snow Level
1000'
Thursday Morning Snow Level
1500'
(Easterly Flow *)
Thursday Mid-day Snow Level
2000'
(Easterly Flow *)
Thursday Afternoon Snow Level
2500'
(Easterly Flow *)
Thursday Night Snow Level
3000'
(Easterly Flow *)
Washington Pass Elevation
Wednesday - Wednesday Night Snow Level
0'
Thursday Morning Snow Level
500'
(Easterly Flow *)
Thursday Mid-day Snow Level
1000'
(Easterly Flow *)
Thursday Afternoon Snow Level
1000'
(Easterly Flow *)
Thursday Night Snow Level
1500'
(Easterly Flow *)
Leavenworth Elevation
Wednesday - Wednesday Night Snow Level
'
Thursday Morning Snow Level
'
(Easterly Flow *)
Thursday Mid-day Snow Level
'
(Easterly Flow *)
Thursday Afternoon Snow Level
'
(Easterly Flow *)
Thursday Night Snow Level
'
(Easterly Flow *)
Stevens Pass Elevation
Wednesday - Wednesday Night Snow Level
'
Thursday Morning Snow Level
'
(Easterly Flow *)
Thursday Mid-day Snow Level
'
(Easterly Flow *)
Thursday Afternoon Snow Level
'
(Easterly Flow *)
Thursday Night Snow Level
'
(Easterly Flow *)
Snoqualmie Pass Elevation
Wednesday - Wednesday Night Snow Level
2000'
Thursday Morning Snow Level
1000'
(Easterly Flow *)
Thursday Mid-day Snow Level
1500'
(Easterly Flow *)
Thursday Afternoon Snow Level
2500'
(Easterly Flow *)
Thursday Night Snow Level
3500'
(Easterly Flow *)
Mt. Rainier & Crystal Elevation
Wednesday - Wednesday Night Snow Level
'
Thursday Morning Snow Level
'
(Easterly Flow *)
Thursday Mid-day Snow Level
'
(Easterly Flow *)
Thursday Afternoon Snow Level
'
(Easterly Flow *)
Thursday Night Snow Level
'
(Easterly Flow *)
Mt. Hood Elevation
Wednesday - Wednesday Night Snow Level
3000'
Thursday Morning Snow Level
3000'
(Easterly Flow *)
Thursday Mid-day Snow Level
4500'
(Easterly Flow *)
Thursday Afternoon Snow Level
7000'
(Easterly Flow *)
Thursday Night Snow Level
6500'
(Easterly Flow *)

* 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

Saturday Saturday
Hurricane Ridge LT 0.25 0 - 0.75
Mt Baker Ski Area LT 0.10 1.00 - 1.50
Washington Pass LT 0.10 0 - 1.00
Stevens Pass LT 0.10 0 - 1.50
Snoqualmie Pass LT 0.25 0 - 2.00
Mission Ridge LT 0.10 0.75 - 1.00
Crystal Mt LT 0.25 1.50 - 2.00
Paradise LT 0.25 2.00 - 3.00
White Pass LT 0.25 0 - 1.50
Mt Hood Meadows 0 - 1.00 3.00 - 4.00
1.00 - 1.50 0 - 4.00

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Wednesday Morning N 5 - 15 N 0 - 10 NW 10 - 20 --- - W 20 - 30
Wednesday Afternoon SE 5 - 15 E 0 - 10 E 0 - 10 --- - W 0 - 10
Wednesday Night - Thursday Morning SE 10 - 20 ESE 5 - 15 SE 10 - 20 --- - SE 10 - 20
Thursday Afternoon S 5 - 15 ESE 5 - 15 SE 10 - 20 --- - SW 30 - 40
Hurricane Ridge Elevation
Wednesday Morning N 5 - 15
Wednesday Afternoon SE 5 - 15
Wednesday Night - Thursday Morning SE 10 - 20
Thursday Afternoon S 5 - 15
Thursday Night S 10 - 20
Mt. Baker Elevation
Wednesday Morning N 0 - 10
Wednesday Afternoon E 0 - 10
Wednesday Night - Thursday Morning ESE 5 - 15
Thursday Afternoon ESE 5 - 15
Thursday Night SE 10 - 20
Stevens and Snoqualmie Pass Elevation
Wednesday Morning NW 10 - 20
Wednesday Afternoon E 0 - 10
Wednesday Night - Thursday Morning SE 10 - 20
Thursday Afternoon SE 10 - 20
Thursday Night SE 15 - 25
Mt. Rainier Elevation
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night - Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night --- -
Mt. Hood Elevation
Wednesday Morning W 20 - 30
Wednesday Afternoon W 0 - 10
Wednesday Night - Thursday Morning SE 10 - 20
Thursday Afternoon SW 30 - 40
Thursday Night SW 45 - 55
Hurricane Ridge Direction - Speed
Wednesday Morning N 5 - 15
Wednesday Afternoon SE 5 - 15
Wednesday Night - Thursday Morning SE 10 - 20
Thursday Afternoon S 5 - 15
Thursday Night S 10 - 20
Mt. Baker Direction - Speed
Wednesday Morning N 0 - 10
Wednesday Afternoon E 0 - 10
Wednesday Night - Thursday Morning ESE 5 - 15
Thursday Afternoon ESE 5 - 15
Thursday Night SE 10 - 20
Stevens and Snoqualmie Pass Direction - Speed
Wednesday Morning NW 10 - 20
Wednesday Afternoon E 0 - 10
Wednesday Night - Thursday Morning SE 10 - 20
Thursday Afternoon SE 10 - 20
Thursday Night SE 15 - 25
Mt. Rainier Direction - Speed
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night - Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night --- -
Mt. Hood Direction - Speed
Wednesday Morning W 20 - 30
Wednesday Afternoon W 0 - 10
Wednesday Night - Thursday Morning SE 10 - 20
Thursday Afternoon SW 30 - 40
Thursday Night SW 45 - 55

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
Wednesday Morning N 10 - 20 N 15 - 25 NW 20 - 30 --- - NW 30 - 40
Wednesday Afternoon NE 10 - 20 N 10 - 20 NNE 10 - 20 --- - NW 15 - 25
Wednesday Night - Thursday Morning S 10 - 20 S 10 - 20 SW 15 - 25 --- - WSW 40 - 50
Thursday Afternoon SW 15 - 25 SW 10 - 20 SW 30 - 40 --- - WSW 40 - 50
Mt. Baker Direction - Speed
Wednesday Morning N 10 - 20
Wednesday Afternoon NE 10 - 20
Wednesday Night - Thursday Morning S 10 - 20
Thursday Afternoon SW 15 - 25
Thursday Night SW 35 - 45
Washington Pass Direction - Speed
Wednesday Morning N 15 - 25
Wednesday Afternoon N 10 - 20
Wednesday Night - Thursday Morning S 10 - 20
Thursday Afternoon SW 10 - 20
Thursday Night SSW 25 - 35
Stevens and Snoqualmie Pass Direction - Speed
Wednesday Morning NW 20 - 30
Wednesday Afternoon NNE 10 - 20
Wednesday Night - Thursday Morning SW 15 - 25
Thursday Afternoon SW 30 - 40
Thursday Night SW 40 - 50
Mt. Rainier Direction - Speed
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night - Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night --- -
Mt. Hood Direction - Speed
Wednesday Morning NW 30 - 40
Wednesday Afternoon NW 15 - 25
Wednesday Night - Thursday Morning WSW 40 - 50
Thursday Afternoon WSW 40 - 50
Thursday Night WSW 60 - 80

Extended Weather Synopsis for Saturday night through Saturday

A switch to westerly flow Friday morning should briefly bump up snow levels to around 4000 feet in the Cascade Passes.  A cooler more homogeneous air mass will settle in over the area Friday afternoon with post-front showers mainly along the west slopes.  

Light showers and cool snow levels will continue through Saturday. The next system should arrive Saturday night and stay relatively cool throughout the event. Steady precipitation should transition to showers during the day Sunday. 

Extended Weather

Olympics, Washington Cascades and Mt. Hood Area
Friday Morning

Light to moderate rain and snow showers, heaviest west slopes of the Cascades. Brief warming trend Cascade Passes with a switch to west winds.  

Friday Afternoon

Mostly cloudy with light rain and snow showers. 

Friday Night - Saturday

Partly to mostly cloudy with scattered light snow showers.  Steady snow developing Olympics Saturday afternoon. 

Saturday Night - Sunday Morning

Moderate snow, except occasionally heavy west slopes of the Washington Cascades. 

Sunday Afternoon

Mostly cloudy with light to moderate showers. 

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Friday Morning Snow Level 2500' - 3500' 3000' - 4000' 3500' - 4500'
Friday Afternoon Snow Level 2000' - 3000' 2000' - 3000' 2500' - 3500' *
Friday Night - Saturday Snow Level 1500' - 2500' 1500' - 2500' 1500' - 2500' *
Mt. Baker Elevation
Friday Morning Snow Level
2500' - 3500'
Friday Afternoon Snow Level
2000' - 3000'
(Easterly Flow *)
Friday Night - Saturday Snow Level
1500' - 2500'
(Easterly Flow *)
Saturday Night - Sunday Snow Level
2000' - 3000'
Snoqualmie Pass Elevation
Friday Morning Snow Level
3000' - 4000'
Friday Afternoon Snow Level
2000' - 3000'
(Easterly Flow *)
Friday Night - Saturday Snow Level
1500' - 2500'
(Easterly Flow *)
Saturday Night - Sunday Snow Level
2000' - 3000'
Mt. Hood Elevation
Friday Morning Snow Level
3500' - 4500'
Friday Afternoon Snow Level
2500' - 3500'
(Easterly Flow *)
Friday Night - Saturday Snow Level
1500' - 2500'
(Easterly Flow *)
Saturday Night - Sunday Snow Level
2000' - 3000'

* 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.

Jump to: Weather Forecast I Snow/Freezing Level I Precipitation I Free Winds 5k I Free Winds 9k I Extended Weather

Previous forecast from Dec 11, 2015

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