Issued: 7:57 AM PST Thursday, December 28, 2017
by Robert Hahn

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

Weather Synopsis for Thursday & Thursday

The Northwest will experience a very active weather pattern Thursday and Friday with moist systems crossing the Pacific Northwest.

On Thursday, strong westerly flow over a flat ridge will carry an occluded front east and south across the NW during the daylight hours. This will bring increasing moderate crest-level winds, increasing moderate to heavy rain and snow, along with rising snow levels. Stevens Pass should remain snow during the daylight hours while Snoqualmie should see a mix of rain and freezing rain at pass level.

The frontal zone will remain over the South Cascades and Hood zones tonight and snow levels should remain steady in most areas.

On Friday, another moist system arrives on a SW flow. This surface low will be developing arrives along with a cold front on Friday evening, tracking across NW Washington State. Crest level winds ahead of the low will be moderate to strong in the central Cascades, with strong winds in the S. Cascades and Mt. Hood areas.

A strong W-SW flow will be ushered in behind the front Friday night along with lowering snow levels and a changeover to snow at pass levels around midnight.

Weather Forecast

Olympics
Thursday Increasing light rain and snow. Rising snow levels.
Thursday Night Occasional light rain and snow.
Friday Increasing light to moderate rain and snow.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Thursday Increasing light to moderate rain/snow in the morning becoming moderate rain/snow in the afternoon. Freezing rain or rain at Snoqualmie.
Thursday Night Light rain and snow in the north, with moderate to heavy rain/snow central and south.
Friday Light to moderate rain/snow north with renewed moderate to heavy rain/snow central and south.
East Slopes of the Washington Cascades
Thursday Increasing light rain/snow in the morning becoming increasing light to moderate rain/snow in the afternoon.
Thursday Night Light rain/snow north, with light to moderate rain/snow central and south.
Friday Light to moderate rain/snow north, with renewed moderate to heavy rain/snow central and south.
Mt. Hood
Thursday Cloudy in the morning with increasing light rain/snow in the afternoon.
Thursday Night Heavy rain and snow.
Friday Decreasing moderate to heavy rain/snow in the morning, with renewed heavy rain/snow in the afternoon.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Thursday Morning Snow Level 4000' 3000' 3000' ' ' 3500' ' 4000'
Thursday Afternoon Snow Level * 4500' 3000' 3000' ' ' 4000' ' 5000'
Thursday Night Snow Level * 5500' 3500' 3500' ' ' 6500' ' 8000'
Friday Morning Snow Level * 5000' 4000' 3500' ' ' 5500' ' 7000'
Friday Afternoon Snow Level * 6000' 4000' 3000' ' ' 6500' ' 7000'
Hurricane Ridge Elevation
Thursday Morning Snow Level
4000'
Thursday Afternoon Snow Level
4500'
(Easterly Flow *)
Thursday Night Snow Level
5500'
(Easterly Flow *)
Friday Morning Snow Level
5000'
(Easterly Flow *)
Friday Afternoon Snow Level
6000'
(Easterly Flow *)
Friday Night Snow Level
2500'
Mt. Baker Elevation
Thursday Morning Snow Level
3000'
Thursday Afternoon Snow Level
3000'
(Easterly Flow *)
Thursday Night Snow Level
3500'
(Easterly Flow *)
Friday Morning Snow Level
4000'
(Easterly Flow *)
Friday Afternoon Snow Level
4000'
(Easterly Flow *)
Friday Night Snow Level
2000'
Washington Pass Elevation
Thursday Morning Snow Level
3000'
Thursday Afternoon Snow Level
3000'
(Easterly Flow *)
Thursday Night Snow Level
3500'
(Easterly Flow *)
Friday Morning Snow Level
3500'
(Easterly Flow *)
Friday Afternoon Snow Level
3000'
(Easterly Flow *)
Friday Night Snow Level
3500'
Leavenworth Elevation
Thursday Morning Snow Level
'
Thursday Afternoon Snow Level
'
(Easterly Flow *)
Thursday Night Snow Level
'
(Easterly Flow *)
Friday Morning Snow Level
'
(Easterly Flow *)
Friday Afternoon Snow Level
'
(Easterly Flow *)
Friday Night Snow Level
'
Stevens Pass Elevation
Thursday Morning Snow Level
'
Thursday Afternoon Snow Level
'
(Easterly Flow *)
Thursday Night Snow Level
'
(Easterly Flow *)
Friday Morning Snow Level
'
(Easterly Flow *)
Friday Afternoon Snow Level
'
(Easterly Flow *)
Friday Night Snow Level
'
Snoqualmie Pass Elevation
Thursday Morning Snow Level
3500'
Thursday Afternoon Snow Level
4000'
(Easterly Flow *)
Thursday Night Snow Level
6500'
(Easterly Flow *)
Friday Morning Snow Level
5500'
(Easterly Flow *)
Friday Afternoon Snow Level
6500'
(Easterly Flow *)
Friday Night Snow Level
3500'
Mt. Rainier & Crystal Elevation
Thursday Morning Snow Level
'
Thursday Afternoon Snow Level
'
(Easterly Flow *)
Thursday Night Snow Level
'
(Easterly Flow *)
Friday Morning Snow Level
'
(Easterly Flow *)
Friday Afternoon Snow Level
'
(Easterly Flow *)
Friday Night Snow Level
'
Mt. Hood Elevation
Thursday Morning Snow Level
4000'
Thursday Afternoon Snow Level
5000'
(Easterly Flow *)
Thursday Night Snow Level
8000'
(Easterly Flow *)
Friday Morning Snow Level
7000'
(Easterly Flow *)
Friday Afternoon Snow Level
7000'
(Easterly Flow *)
Friday Night Snow Level
5000'

* 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

Thursday Thursday
Hurricane Ridge LT 0.25 0 - 0.75
Mt Baker Ski Area 0 - 0.75 0.75 - 1.00
Washington Pass 0 - 0.50 0.75 - 1.00
Stevens Pass 1.00 - 1.50 0 - 2.00
Snoqualmie Pass 1.50 - 2.00 2.00 - 3.00
Mission Ridge 0.25 - 0.50 0 - 1.00
Crystal Mt 0 - 1.00 0 - 1.50
Paradise 0 - 3.00 0 - 3.00
White Pass 1.50 - 2.00 0 - 2.00
Mt Hood Meadows 2.00 - 3.00 1.50 - 2.00
0 - 3.00 0 - 2.00

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Thursday Morning SW 20 - 30 SSW 20 - 30 SW 20 - 30 --- - SW 15 - 25
Thursday Afternoon SW 20 - 30 S 20 - 30 SSW 20 - 30 --- - SW 30 - 40
Thursday Night SW 5 - 15 N 0 - 10 SW 15 - 25 --- - SW 40 - 60
Friday Morning SE 15 - 25 ESE 5 - 15 S 20 - 30 --- - SW 40 - 60
Friday Afternoon SSW 15 - 25 ESE 15 - 25 S 25 - 35 --- - SW 40 - 60
Hurricane Ridge Elevation
Thursday Morning SW 20 - 30
Thursday Afternoon SW 20 - 30
Thursday Night SW 5 - 15
Friday Morning SE 15 - 25
Friday Afternoon SSW 15 - 25
Friday Night WSW 25 - 35
Mt. Baker Elevation
Thursday Morning SSW 20 - 30
Thursday Afternoon S 20 - 30
Thursday Night N 0 - 10
Friday Morning ESE 5 - 15
Friday Afternoon ESE 15 - 25
Friday Night WSW 20 - 30
Stevens and Snoqualmie Pass Elevation
Thursday Morning SW 20 - 30
Thursday Afternoon SSW 20 - 30
Thursday Night SW 15 - 25
Friday Morning S 20 - 30
Friday Afternoon S 25 - 35
Friday Night SSW 30 - 40
Mt. Rainier Elevation
Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night --- -
Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Mt. Hood Elevation
Thursday Morning SW 15 - 25
Thursday Afternoon SW 30 - 40
Thursday Night SW 40 - 60
Friday Morning SW 40 - 60
Friday Afternoon SW 40 - 60
Friday Night WSW 40 - 60
Hurricane Ridge Direction - Speed
Thursday Morning SW 20 - 30
Thursday Afternoon SW 20 - 30
Thursday Night SW 5 - 15
Friday Morning SE 15 - 25
Friday Afternoon SSW 15 - 25
Friday Night WSW 25 - 35
Mt. Baker Direction - Speed
Thursday Morning SSW 20 - 30
Thursday Afternoon S 20 - 30
Thursday Night N 0 - 10
Friday Morning ESE 5 - 15
Friday Afternoon ESE 15 - 25
Friday Night WSW 20 - 30
Stevens and Snoqualmie Pass Direction - Speed
Thursday Morning SW 20 - 30
Thursday Afternoon SSW 20 - 30
Thursday Night SW 15 - 25
Friday Morning S 20 - 30
Friday Afternoon S 25 - 35
Friday Night SSW 30 - 40
Mt. Rainier Direction - Speed
Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night --- -
Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Mt. Hood Direction - Speed
Thursday Morning SW 15 - 25
Thursday Afternoon SW 30 - 40
Thursday Night SW 40 - 60
Friday Morning SW 40 - 60
Friday Afternoon SW 40 - 60
Friday Night WSW 40 - 60

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
Thursday Morning WSW 30 - 40 WSW 30 - 40 WSW 30 - 40 --- - WSW 45 - 65
Thursday Afternoon SW 35 - 50 SW 35 - 50 SW 40 - 60 --- - WSW 70 - 90
Thursday Night WSW 25 - 35 WSW 30 - 40 WSW 30 - 50 --- - WSW 50 - 80
Friday Morning S 15 - 25 SSW 15 - 25 SW 40 - 60 --- - SW 55 - 75
Friday Afternoon SW 35 - 50 SW 30 - 40 SW 55 - 75 --- - WSW 55 - 75
Mt. Baker Direction - Speed
Thursday Morning WSW 30 - 40
Thursday Afternoon SW 35 - 50
Thursday Night WSW 25 - 35
Friday Morning S 15 - 25
Friday Afternoon SW 35 - 50
Friday Night WSW 40 - 60
Washington Pass Direction - Speed
Thursday Morning WSW 30 - 40
Thursday Afternoon SW 35 - 50
Thursday Night WSW 30 - 40
Friday Morning SSW 15 - 25
Friday Afternoon SW 30 - 40
Friday Night WSW 50 - 70
Stevens and Snoqualmie Pass Direction - Speed
Thursday Morning WSW 30 - 40
Thursday Afternoon SW 40 - 60
Thursday Night WSW 30 - 50
Friday Morning SW 40 - 60
Friday Afternoon SW 55 - 75
Friday Night WSW 45 - 65
Mt. Rainier Direction - Speed
Thursday Morning --- -
Thursday Afternoon --- -
Thursday Night --- -
Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Mt. Hood Direction - Speed
Thursday Morning WSW 45 - 65
Thursday Afternoon WSW 70 - 90
Thursday Night WSW 50 - 80
Friday Morning SW 55 - 75
Friday Afternoon WSW 55 - 75
Friday Night WSW 50 - 70

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.

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

Previous forecast from Dec 27, 2017

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