Issued: 1:51 PM PST Friday, December 29, 2017
by Robert Hahn

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

Weather Synopsis for Friday & Saturday

A brief, strong SW flow will carry a moderately deepening surface low across Cape Flattery, by around 4PM. A strong cold front will accompany the surface low and will cross the Northwest during the early evening hours. Generally increasingly strong S or SE winds ahead of the front will shift to W-SW behind the front and become stronger. Temperatures will drop sharply in all areas behind the front as most areas turn back to snow overnight Friday.

On Saturday, a moderate ridge and drier airmass begins moving over the US coastal waters.

Weather Forecast

Olympics
Friday Increasing light to moderate rain and snow. Strong crest-level wind.
Friday Night Decreasing light rain and snow showers with strong W-SW winds and rapidly dropping temperatures.
Saturday Light snow showers ending in the morning, with clouds in the afternoon. Decreasing westerly winds.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Friday Increasing moderate to heavy rain and snow accompanied by strong crest-level wind.
Friday Night Decreasing moderate rain and snow showers in the evening, becoming light to moderate snow showers after midnight, heaviest in the mountain loop area. Strong W-SW winds.
Saturday Decreasing light to moderate snow showers in the morning becoming isolated, light snow showers in the afternoon.
East Slopes of the Washington Cascades
Friday Increasing moderate to heavy rain and snow accompanied by strong crest-level wind.
Friday Night Decreasing moderate rain and snow showers in the evening, becoming light to moderate snow showers after midnight, heaviest at higher elevations. Strong W-SW winds.
Saturday Decreasing light to moderate snow showers at higher elevations in the morning becoming isolated, light snow showers at higher elevations in the afternoon.
Mt. Hood
Friday Decreasing light rain and high elevation snow in the morning. Increasing moderate to heavy rain and high elevation snow in the afternoon. Very strong crest-level winds.
Friday Night Heavy rain and high elevation snow in the evening trending to light rain and snow showers after midnight. Strong W-SW crest level winds.
Saturday Decreasing light snow showers in the morning.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Friday Afternoon Snow Level * 7000' 5000' 3000' ' ' 6500' ' 7500'
Friday Night Snow Level 2500' 2500' 4000' ' ' 3000' ' 4500'
Saturday Morning Snow Level 2000' 1000' 1000' ' ' 2000' ' 2500'
Saturday Afternoon Snow Level 2000' 1000' 1000' ' ' 2000' ' 3000'
Hurricane Ridge Elevation
Friday Afternoon Snow Level
7000'
(Easterly Flow *)
Friday Night Snow Level
2500'
Saturday Morning Snow Level
2000'
Saturday Afternoon Snow Level
2000'
Saturday Night Snow Level
3000'
(Easterly Flow *)
Mt. Baker Elevation
Friday Afternoon Snow Level
5000'
(Easterly Flow *)
Friday Night Snow Level
2500'
Saturday Morning Snow Level
1000'
Saturday Afternoon Snow Level
1000'
Saturday Night Snow Level
2000'
(Easterly Flow *)
Washington Pass Elevation
Friday Afternoon Snow Level
3000'
(Easterly Flow *)
Friday Night Snow Level
4000'
Saturday Morning Snow Level
1000'
Saturday Afternoon Snow Level
1000'
Saturday Night Snow Level
2500'
(Easterly Flow *)
Leavenworth Elevation
Friday Afternoon Snow Level
'
(Easterly Flow *)
Friday Night Snow Level
'
Saturday Morning Snow Level
'
Saturday Afternoon Snow Level
'
Saturday Night Snow Level
'
(Easterly Flow *)
Stevens Pass Elevation
Friday Afternoon Snow Level
'
(Easterly Flow *)
Friday Night Snow Level
'
Saturday Morning Snow Level
'
Saturday Afternoon Snow Level
'
Saturday Night Snow Level
'
(Easterly Flow *)
Snoqualmie Pass Elevation
Friday Afternoon Snow Level
6500'
(Easterly Flow *)
Friday Night Snow Level
3000'
Saturday Morning Snow Level
2000'
Saturday Afternoon Snow Level
2000'
Saturday Night Snow Level
3000'
(Easterly Flow *)
Mt. Rainier & Crystal Elevation
Friday Afternoon Snow Level
'
(Easterly Flow *)
Friday Night Snow Level
'
Saturday Morning Snow Level
'
Saturday Afternoon Snow Level
'
Saturday Night Snow Level
'
(Easterly Flow *)
Mt. Hood Elevation
Friday Afternoon Snow Level
7500'
(Easterly Flow *)
Friday Night Snow Level
4500'
Saturday Morning Snow Level
2500'
Saturday Afternoon Snow Level
3000'
Saturday Night Snow Level
4500'
(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 1.00 - 1.50 LT 0.10
Mt Baker Ski Area 0 - 1.50 0.25 - 0.50
Washington Pass 0 - 1.50 LT 0.25
Stevens Pass 1.50 - 2.00 0.25 - 0.50
Snoqualmie Pass 2.00 - 2.50 0.25 - 0.50
Mission Ridge 0 - 1.00 LT 0.25
Crystal Mt 1.50 - 2.00 LT 0.25
Paradise 3.00 - 4.00 0.25 - 0.50
White Pass 1.50 - 2.00 LT 0.25
Mt Hood Meadows 0 - 1.00 LT 0.10
1.00 - 1.50 LT 0.25

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Friday Afternoon S 25 - 35 ESE 20 - 30 SSE 25 - 35 --- - SSW 45 - 65
Friday Night WSW 30 - 40 SW 25 - 35 SW 40 - 60 --- - WSW 40 - 60
Saturday Morning W 20 - 30 W 20 - 30 W 20 - 30 --- - WSW 20 - 30
Saturday Afternoon W 10 - 20 W 5 - 15 W 10 - 20 --- - W 10 - 20
Hurricane Ridge Elevation
Friday Afternoon S 25 - 35
Friday Night WSW 30 - 40
Saturday Morning W 20 - 30
Saturday Afternoon W 10 - 20
Saturday Night VAR 0 - 10
Mt. Baker Elevation
Friday Afternoon ESE 20 - 30
Friday Night SW 25 - 35
Saturday Morning W 20 - 30
Saturday Afternoon W 5 - 15
Saturday Night VAR 0 - 10
Stevens and Snoqualmie Pass Elevation
Friday Afternoon SSE 25 - 35
Friday Night SW 40 - 60
Saturday Morning W 20 - 30
Saturday Afternoon W 10 - 20
Saturday Night VAR 0 - 10
Mt. Rainier Elevation
Friday Afternoon --- -
Friday Night --- -
Saturday Morning --- -
Saturday Afternoon --- -
Saturday Night --- -
Mt. Hood Elevation
Friday Afternoon SSW 45 - 65
Friday Night WSW 40 - 60
Saturday Morning WSW 20 - 30
Saturday Afternoon W 10 - 20
Saturday Night E 0 - 10
Hurricane Ridge Direction - Speed
Friday Afternoon S 25 - 35
Friday Night WSW 30 - 40
Saturday Morning W 20 - 30
Saturday Afternoon W 10 - 20
Saturday Night VAR 0 - 10
Mt. Baker Direction - Speed
Friday Afternoon ESE 20 - 30
Friday Night SW 25 - 35
Saturday Morning W 20 - 30
Saturday Afternoon W 5 - 15
Saturday Night VAR 0 - 10
Stevens and Snoqualmie Pass Direction - Speed
Friday Afternoon SSE 25 - 35
Friday Night SW 40 - 60
Saturday Morning W 20 - 30
Saturday Afternoon W 10 - 20
Saturday Night VAR 0 - 10
Mt. Rainier Direction - Speed
Friday Afternoon --- -
Friday Night --- -
Saturday Morning --- -
Saturday Afternoon --- -
Saturday Night --- -
Mt. Hood Direction - Speed
Friday Afternoon SSW 45 - 65
Friday Night WSW 40 - 60
Saturday Morning WSW 20 - 30
Saturday Afternoon W 10 - 20
Saturday Night E 0 - 10

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
Friday Afternoon SSW 45 - 65 SW 40 - 60 SW 55 - 75 --- - SW 60 - 80
Friday Night SW 45 - 65 SW 50 - 70 SW 50 - 70 --- - SW 50 - 70
Saturday Morning W 25 - 35 W 35 - 50 WNW 30 - 40 --- - W 30 - 40
Saturday Afternoon W 20 - 30 W 20 - 30 W 30 - 40 --- - WNW 25 - 35
Mt. Baker Direction - Speed
Friday Afternoon SSW 45 - 65
Friday Night SW 45 - 65
Saturday Morning W 25 - 35
Saturday Afternoon W 20 - 30
Saturday Night NW 15 - 25
Washington Pass Direction - Speed
Friday Afternoon SW 40 - 60
Friday Night SW 50 - 70
Saturday Morning W 35 - 50
Saturday Afternoon W 20 - 30
Saturday Night W 10 - 20
Stevens and Snoqualmie Pass Direction - Speed
Friday Afternoon SW 55 - 75
Friday Night SW 50 - 70
Saturday Morning WNW 30 - 40
Saturday Afternoon W 30 - 40
Saturday Night WNW 15 - 25
Mt. Rainier Direction - Speed
Friday Afternoon --- -
Friday Night --- -
Saturday Morning --- -
Saturday Afternoon --- -
Saturday Night --- -
Mt. Hood Direction - Speed
Friday Afternoon SW 60 - 80
Friday Night SW 50 - 70
Saturday Morning W 30 - 40
Saturday Afternoon WNW 25 - 35
Saturday Night WNW 10 - 20

Extended Weather Synopsis for Saturday night through Saturday

Another upper ridge will linger off the U.S. west coast Sunday-Tuesday. This time-frame will also feature offshore surface flow.

Extended Weather

Olympics, Washington Cascades and Mt. Hood Area
Sunday Sunny. Monday Mostly fair with some mid and high clouds at times. Tuesday Mostly fair with some mid and high clouds at times.

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Sunday Freezing Level 4500' - 5500' 3500' - 4500' 10000' - 11000' *
Sunday Night Freezing Level 7500' - 8500' 4500' - 5500' 9500' - 10500' *
Monday Freezing Level 7500' - 8500' 5000' - 6000' 9500' - 10500' *
Monday Night Freezing Level 6500' - 7500' 6000' - 7000' 9000' - 10000' *
Mt. Baker Elevation
Sunday Freezing Level
4500' - 5500'
(Easterly Flow *)
Sunday Night Freezing Level
7500' - 8500'
(Easterly Flow *)
Monday Freezing Level
7500' - 8500'
(Easterly Flow *)
Monday Night Freezing Level
6500' - 7500'
(Easterly Flow *)
Tuesday Freezing Level
7000' - 9000'
(Easterly Flow *)
Snoqualmie Pass Elevation
Sunday Freezing Level
3500' - 4500'
(Easterly Flow *)
Sunday Night Freezing Level
4500' - 5500'
(Easterly Flow *)
Monday Freezing Level
5000' - 6000'
(Easterly Flow *)
Monday Night Freezing Level
6000' - 7000'
(Easterly Flow *)
Tuesday Freezing Level
6000' - 8000'
(Easterly Flow *)
Mt. Hood Elevation
Sunday Freezing Level
10000' - 11000'
(Easterly Flow *)
Sunday Night Freezing Level
9500' - 10500'
(Easterly Flow *)
Monday Freezing Level
9500' - 10500'
(Easterly Flow *)
Monday Night Freezing Level
9000' - 10000'
(Easterly Flow *)
Tuesday Freezing Level
9000' - 11000'
(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.

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 29, 2017

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