Issued: 2:39 PM PST Wednesday, January 20, 2016
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 & Tuesday

Afternoon update: Minor changes mainly for Day 2 precipitation forecast and snow levels. Introduced a period of potential freezing rain for the Passes late tonight through Thursday morning and for the lower slopes of the east Cascades Thursday morning through mid-day. 

A low pressure system passing through Oregon brought up to 2 feet of snow through early this morning at Mt. Hood with about a foot at Paradise and a few inches further north.  NW flow in the wake of the low pressure system should deliver some light to moderate showers through mid-day for the west slopes of the Cascades and Mt. Hood. 

A transient upper level ridge will pass over the area this afternoon and shift east toward Idaho overnight. A Pacific frontal system currently offshore should spread precipitation into the area overnight. 

The frontal boundary will slow offshore on Thursday and become north-south oriented, with the axis of the heaviest precipitation focusing into southern British Columbia, the Olympics and the Washington north Cascades. Much lighter amounts of precipitation are expected further south and along the east slopes. This system will also feature strong southerly winds that should ramp up late Wednesday night and continue through Thursday evening. Warm air should be pumped into the region due to the extended period of southerly flow, with even the Cascade Passes becoming subject to free-air snow levels by Thursday afternoon. 

Weather Forecast

Olympics and northwest Cascades (Mt. Baker area)
Wednesday

Mostly cloudy with light rain and snow showers. Increasing high clouds in the afternoon. 

Wednesday Night

Light rain and snow developing and becoming moderate overnight. Winds increasing with a slow warming trend. 

Thursday - Thursday Evening

Stormy with moderate to heavy rain and snow. Warming trend through the afternoon. 

Central and south Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
Wednesday

Mostly cloudy with light to occasionally moderate rain and snow showers. Increasing high clouds in the afternoon. 

Wednesday Night

Light to occasionally moderate rain and snow developing overnight. Freezing rain possible Cascade Passes late tonight. Winds increasing overnight. 

Thursday - Thursday Evening

Light rain and snow. Freezing rain possible Cascade Passes Thursday morning.  Windy. Warming trend including Cascades Passes.  

East slopes of the Washington Cascades
Wednesday

Partly to mostly cloudy with light rain and snow showers near the crest. Increasing high clouds late in the afternoon. 

Wednesday Night

Light rain and snow developing overnight. Winds increasing overnight. 

Thursday - Thursday Evening

Light rain and snow. Freezing rain possible Thursday morning through mid-day lower slopes and valleys. Windy. Warming trend in the afternoon.   

Mt. Hood Area
Wednesday

Mostly cloudy with light to occasionally moderate rain and snow showers. Increasing high clouds in the afternoon. 

Wednesday Night

Light rain and snow developing overnight. Winds increasing overnight. Slow warming trend. 

Thursday - Thursday Evening

Light rain and snow. Windy. Mild.   

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Wednesday Afternoon Snow Level * 4500' 3500' 3000' ' ' 4500' ' 5500'
Wednesday Night Snow Level * 6000' 3500' 2500' ' ' 3000' ' 6000'
Thursday Morning Snow Level * 7000' 4500' 2500' ' ' 4000' ' 7000'
Thursday Afternoon - Thursday Evening Snow Level * 7500' 6500' 4500' ' ' 7000' ' 7500'
Hurricane Ridge Elevation
Wednesday Afternoon Snow Level
4500'
(Easterly Flow *)
Wednesday Night Snow Level
6000'
(Easterly Flow *)
Thursday Morning Snow Level
7000'
(Easterly Flow *)
Thursday Afternoon - Thursday Evening Snow Level
7500'
(Easterly Flow *)
Thursday Night Snow Level
6500'
(Easterly Flow *)
Mt. Baker Elevation
Wednesday Afternoon Snow Level
3500'
(Easterly Flow *)
Wednesday Night Snow Level
3500'
(Easterly Flow *)
Thursday Morning Snow Level
4500'
(Easterly Flow *)
Thursday Afternoon - Thursday Evening Snow Level
6500'
(Easterly Flow *)
Thursday Night Snow Level
6000'
(Easterly Flow *)
Washington Pass Elevation
Wednesday Afternoon Snow Level
3000'
(Easterly Flow *)
Wednesday Night Snow Level
2500'
(Easterly Flow *)
Thursday Morning Snow Level
2500'
(Easterly Flow *)
Thursday Afternoon - Thursday Evening Snow Level
4500'
(Easterly Flow *)
Thursday Night Snow Level
4000'
(Easterly Flow *)
Leavenworth Elevation
Wednesday Afternoon Snow Level
'
(Easterly Flow *)
Wednesday Night Snow Level
'
(Easterly Flow *)
Thursday Morning Snow Level
'
(Easterly Flow *)
Thursday Afternoon - Thursday Evening Snow Level
'
(Easterly Flow *)
Thursday Night Snow Level
'
(Easterly Flow *)
Stevens Pass Elevation
Wednesday Afternoon Snow Level
'
(Easterly Flow *)
Wednesday Night Snow Level
'
(Easterly Flow *)
Thursday Morning Snow Level
'
(Easterly Flow *)
Thursday Afternoon - Thursday Evening Snow Level
'
(Easterly Flow *)
Thursday Night Snow Level
'
(Easterly Flow *)
Snoqualmie Pass Elevation
Wednesday Afternoon Snow Level
4500'
(Easterly Flow *)
Wednesday Night Snow Level
3000'
(Easterly Flow *)
Thursday Morning Snow Level
4000'
(Easterly Flow *)
Thursday Afternoon - Thursday Evening Snow Level
7000'
(Easterly Flow *)
Thursday Night Snow Level
5500'
(Easterly Flow *)
Mt. Rainier & Crystal Elevation
Wednesday Afternoon Snow Level
'
(Easterly Flow *)
Wednesday Night Snow Level
'
(Easterly Flow *)
Thursday Morning Snow Level
'
(Easterly Flow *)
Thursday Afternoon - Thursday Evening Snow Level
'
(Easterly Flow *)
Thursday Night Snow Level
'
(Easterly Flow *)
Mt. Hood Elevation
Wednesday Afternoon Snow Level
5500'
(Easterly Flow *)
Wednesday Night Snow Level
6000'
(Easterly Flow *)
Thursday Morning Snow Level
7000'
(Easterly Flow *)
Thursday Afternoon - Thursday Evening Snow Level
7500'
(Easterly Flow *)
Thursday Night Snow Level
5500'
(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

Tuesday Tuesday
Hurricane Ridge 0 - 0.50 1.50 - 2.50
Mt Baker Ski Area 0 - 1.00 3.00 - 5.00
Washington Pass LT 0.25 1.00 - 1.50
Stevens Pass 0.25 - 0.50 0.50 - 1.00
Snoqualmie Pass 0.50 - 0.75 0.50 - 1.00
Mission Ridge LT 0.25 0 - 0.50
Crystal Mt 0.25 - 0.50 0.75 - 1.00
Paradise 0.75 - 1.00 0 - 0.75
White Pass 0.25 - 0.50 LT 0.25
Mt Hood Meadows 0 - 0.50 LT 0.25
0 - 0.50 0.25 - 0.50

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Wednesday Afternoon SE 15 - 25 S 5 - 15 S 5 - 15 --- - S 10 - 20
Wednesday Night S 35 - 45 SE 15 - 25 SSE 15 - 30 --- - S 15 - 25
Hurricane Ridge Elevation
Wednesday Afternoon SE 15 - 25
Wednesday Night S 35 - 45
Thursday - Thursday Night S 45 - 60
Mt. Baker Elevation
Wednesday Afternoon S 5 - 15
Wednesday Night SE 15 - 25
Thursday - Thursday Night SW 35 - 45
Stevens and Snoqualmie Pass Elevation
Wednesday Afternoon S 5 - 15
Wednesday Night SSE 15 - 30
Thursday - Thursday Night SSE 20 - 35
Mt. Rainier Elevation
Wednesday Afternoon --- -
Wednesday Night --- -
Thursday - Thursday Night --- -
Mt. Hood Elevation
Wednesday Afternoon S 10 - 20
Wednesday Night S 15 - 25
Thursday - Thursday Night S 15 - 30
Hurricane Ridge Direction - Speed
Wednesday Afternoon SE 15 - 25
Wednesday Night S 35 - 45
Thursday - Thursday Night S 45 - 60
Mt. Baker Direction - Speed
Wednesday Afternoon S 5 - 15
Wednesday Night SE 15 - 25
Thursday - Thursday Night SW 35 - 45
Stevens and Snoqualmie Pass Direction - Speed
Wednesday Afternoon S 5 - 15
Wednesday Night SSE 15 - 30
Thursday - Thursday Night SSE 20 - 35
Mt. Rainier Direction - Speed
Wednesday Afternoon --- -
Wednesday Night --- -
Thursday - Thursday Night --- -
Mt. Hood Direction - Speed
Wednesday Afternoon S 10 - 20
Wednesday Night S 15 - 25
Thursday - Thursday Night S 15 - 30

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 Afternoon S 5 - 15 S 10 - 20 SW 15 - 25 --- - SW 15 - 25
Wednesday Night SW 30 - 40 SW 25 - 35 SW 40 - 50 --- - SW 35 - 45
Mt. Baker Direction - Speed
Wednesday Afternoon S 5 - 15
Wednesday Night SW 30 - 40
Thursday - Thursday Night SW 55 - 70
Washington Pass Direction - Speed
Wednesday Afternoon S 10 - 20
Wednesday Night SW 25 - 35
Thursday - Thursday Night SW 40 - 50
Stevens and Snoqualmie Pass Direction - Speed
Wednesday Afternoon SW 15 - 25
Wednesday Night SW 40 - 50
Thursday - Thursday Night SW 45 - 60
Mt. Rainier Direction - Speed
Wednesday Afternoon --- -
Wednesday Night --- -
Thursday - Thursday Night --- -
Mt. Hood Direction - Speed
Wednesday Afternoon SW 15 - 25
Wednesday Night SW 35 - 45
Thursday - Thursday Night SW 40 - 50

Extended Weather Synopsis for Tuesday night through Tuesday

The trailing upper trough should kick the frontal boundary east and through the area Friday morning. Cooler air aloft will bring snow levels down during the day with light to moderate showers through Friday afternoon. 

A low pressure system rotating up from off the California coast should reach Mt. Hood late Friday night into Saturday morning and spread light precipitation northward into Washington State during the day.  Orographic showers favoring the west slopes of the Cascades and Mt. Hood should follow Saturday afternoon through Sunday in NW flow aloft.  

Extended Weather

Olympics, Washington Cascades and Mt. Hood area
Friday - Friday Evening

Cloudy with light to occasionally moderate rain and snow showers, heaviest Mt. Baker area. Slow cooling trend. Showers decreasing in the evening. 

Friday Night - Saturday

Light to moderate rain and snow developing Mt. Hood Friday night and spreading light rain and snow northward during the day. Cloudy south part, partly cloudy north part with increasing clouds Saturday afternoon. Cooler. 

Saturday Night - Sunday

Light rain and snow showers, except occasionally moderate west slopes and Mt. Hood. 

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Friday Morning Snow Level 5500' - 6500' 4500' - 5500' 5000' - 6000'
Friday Afternoon - Friday Night Snow Level 3500' - 4500' 3500' - 4500' 3500' - 4500'
Saturday Snow Level 3000' - 4000' 3000' - 4000' 3000' - 4000'
Mt. Baker Elevation
Friday Morning Snow Level
5500' - 6500'
Friday Afternoon - Friday Night Snow Level
3500' - 4500'
Saturday Snow Level
3000' - 4000'
Saturday Night - Sunday Snow Level
2500' - 3500'
Snoqualmie Pass Elevation
Friday Morning Snow Level
4500' - 5500'
Friday Afternoon - Friday Night Snow Level
3500' - 4500'
Saturday Snow Level
3000' - 4000'
Saturday Night - Sunday Snow Level
2500' - 3500'
Mt. Hood Elevation
Friday Morning Snow Level
5000' - 6000'
Friday Afternoon - Friday Night Snow Level
3500' - 4500'
Saturday Snow Level
3000' - 4000'
Saturday Night - Sunday Snow Level
2500' - 3500'

* 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 Jan 20, 2016

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