Issued: 1:47 PM PST Wednesday, November 18, 2020
by Dallas Glass

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 night through Friday

After a generally wet few days up in the mountains, we'll begin to see a slight shift in the weather Wednesday night through Thursday evening as precipitation very slowly decreases. A cool and wet trough should continue to spin rain and snow into the mountains Wednesday night with the heaviest precipitation focussed on the Cascade volcanoes. As the associated low-pressure shifts inland, there appears to be sufficient energy to increase precipitation in all locations with significant showers spilling over east of the Cascade crest. Expect snow at most trailheads as snowlevels remain below the passes. 

By Thursday morning most places begin to see a decrease in shower activity as westerly winds refocus the remaining moisture on the volcanoes and in a weak convergence zone generally north of I90. A subtle ridge will approach the region late in the day and into the night. As the ridge slides north and east, look for the shower activity to gradually end from south to north. You're most likely to encounter rain and snow showers along the west-slopes of the Cascades from near Stevens Pass north. 

A few isolated showers may linger in the northern half of the region into Friday morning, but most locations will see a dry day. Don't be surprised if you see some blue sky, particularly east of the Cascade crest and areas further south like Mt Hood, White Pass, and Crystal. The weak high-pressure ridge should allow for slight warming Friday afternoon as relatively warmer air seeps in from the Pacific. This break in the action appears to last into the first part of the weekend. 

 

 

Weather Forecast

Hurricane Ridge
Wednesday Night Rain and snow showers particularly in the early evening, becoming more isolated overnight. Light to moderate westerly winds.
Mt. Baker
Wednesday Night Rain and snow overnight. Light to moderate westerly winds increasing after midnight.
Washington Pass and Leavenworth
Wednesday Night Rain and snow showers particularly after midnight. Light westerly winds.
Stevens and Snoqualmie Pass
Wednesday Night Rain and snow showers. Light westerly winds at pass level.
Mt. Rainier, Crystal and White Pass
Wednesday Night Rain and snow, heaviest near the volcanoes. Moderate to strong westerly winds ridgetop winds.
Mt. Hood
Wednesday Night Rain and snow. Strong to very strong westerly winds.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Wednesday Evening Snow Level 3000' 3000' 3000' 3000' 3000' 3000' 3500' 3500'
Wednesday Night Snow Level 2500' 2500' 2500' 2500' 2500' 2500' 3000' 3000'
Thursday Morning Snow Level 2000' 2000' 2000' 2000' 2500' 2500' 2500' 3000'
Thursday Afternoon Snow Level 3000' 2500' 2500' 2500' 3000' 3000' 3500' 3500'
Thursday Evening Snow Level 2500' 2500' 2000' 2000' 2500' 2500' 3000' 3000'
Thursday Night Snow Level 2500' 2500' 2000' 2000' 2500' 2500' 2500' 2500'
Friday Morning Snow Level * 2500' 2500' 2000' 2000' 3000' 3000' 3000' 3000'
Hurricane Ridge Elevation
Wednesday Evening Snow Level
3000'
Wednesday Night Snow Level
2500'
Thursday Morning Snow Level
2000'
Thursday Afternoon Snow Level
3000'
Thursday Evening Snow Level
2500'
Thursday Night Snow Level
2500'
Friday Morning Snow Level
2500'
(Easterly Flow *)
Friday Afternoon Snow Level
3500'
(Easterly Flow *)
Mt. Baker Elevation
Wednesday Evening Snow Level
3000'
Wednesday Night Snow Level
2500'
Thursday Morning Snow Level
2000'
Thursday Afternoon Snow Level
2500'
Thursday Evening Snow Level
2500'
Thursday Night Snow Level
2500'
Friday Morning Snow Level
2500'
(Easterly Flow *)
Friday Afternoon Snow Level
3000'
(Easterly Flow *)
Washington Pass Elevation
Wednesday Evening Snow Level
3000'
Wednesday Night Snow Level
2500'
Thursday Morning Snow Level
2000'
Thursday Afternoon Snow Level
2500'
Thursday Evening Snow Level
2000'
Thursday Night Snow Level
2000'
Friday Morning Snow Level
2000'
(Easterly Flow *)
Friday Afternoon Snow Level
3000'
(Easterly Flow *)
Leavenworth Elevation
Wednesday Evening Snow Level
3000'
Wednesday Night Snow Level
2500'
Thursday Morning Snow Level
2000'
Thursday Afternoon Snow Level
2500'
Thursday Evening Snow Level
2000'
Thursday Night Snow Level
2000'
Friday Morning Snow Level
2000'
(Easterly Flow *)
Friday Afternoon Snow Level
3500'
(Easterly Flow *)
Stevens Pass Elevation
Wednesday Evening Snow Level
3000'
Wednesday Night Snow Level
2500'
Thursday Morning Snow Level
2500'
Thursday Afternoon Snow Level
3000'
Thursday Evening Snow Level
2500'
Thursday Night Snow Level
2500'
Friday Morning Snow Level
3000'
(Easterly Flow *)
Friday Afternoon Snow Level
3500'
(Easterly Flow *)
Snoqualmie Pass Elevation
Wednesday Evening Snow Level
3000'
Wednesday Night Snow Level
2500'
Thursday Morning Snow Level
2500'
Thursday Afternoon Snow Level
3000'
Thursday Evening Snow Level
2500'
Thursday Night Snow Level
2500'
Friday Morning Snow Level
3000'
(Easterly Flow *)
Friday Afternoon Snow Level
3500'
(Easterly Flow *)
Mt. Rainier & Crystal Elevation
Wednesday Evening Snow Level
3500'
Wednesday Night Snow Level
3000'
Thursday Morning Snow Level
2500'
Thursday Afternoon Snow Level
3500'
Thursday Evening Snow Level
3000'
Thursday Night Snow Level
2500'
Friday Morning Snow Level
3000'
(Easterly Flow *)
Friday Afternoon Snow Level
4000'
(Easterly Flow *)
Mt. Hood Elevation
Wednesday Evening Snow Level
3500'
Wednesday Night Snow Level
3000'
Thursday Morning Snow Level
3000'
Thursday Afternoon Snow Level
3500'
Thursday Evening Snow Level
3000'
Thursday Night Snow Level
2500'
Friday Morning Snow Level
3000'
(Easterly Flow *)
Friday Afternoon Snow Level
4000'
(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

Wednesday Night Thursday Thursday Night Friday
4 pm - 4 am 4 am - 4 pm 4 pm - 4 am 4 am - 4 pm
Hurricane Ridge 0.25 LT 0.25 LT 0.10 LT 0.10
Mt Baker Ski Area 1.00 0.25 0.25 LT 0.25
Washington Pass 0.25 LT 0.10 LT 0.25 LT 0.10
Leavenworth LT 0.10 0 LT 0.10 0
Stevens Pass 0.25 - 0.50 0.25 0.25 LT 0.25
Snoqualmie Pass 0.25 - 0.50 0.25 0.25 LT 0.10
Mission Ridge LT 0.10 LT 0.10 LT 0.10 0
Crystal Mt 0.25 LT 0.25 LT 0.10 0
Paradise 0.75 0.50 0.25 0
White Pass 0.50 0.25 LT 0.25 0
Mt Hood Meadows 0.50 - 0.75 0.25 - 0.50 LT 0.10 0
0.75 0.25 - 0.50 LT 0.10 0
Hurricane Ridge Precipitation Forecast
Wednesday Night 0.25
Thursday LT 0.25
Thursday Night LT 0.10
Friday LT 0.10
Mt Baker Ski Area Precipitation Forecast
Wednesday Night 1.00
Thursday 0.25
Thursday Night 0.25
Friday LT 0.25
Washington Pass Precipitation Forecast
Wednesday Night 0.25
Thursday LT 0.10
Thursday Night LT 0.25
Friday LT 0.10
Leavenworth Precipitation Forecast
Wednesday Night LT 0.10
Thursday 0
Thursday Night LT 0.10
Friday 0
Stevens Pass Precipitation Forecast
Wednesday Night 0.25 - 0.50
Thursday 0.25
Thursday Night 0.25
Friday LT 0.25
Snoqualmie Pass Precipitation Forecast
Wednesday Night 0.25 - 0.50
Thursday 0.25
Thursday Night 0.25
Friday LT 0.10
Mission Ridge Precipitation Forecast
Wednesday Night LT 0.10
Thursday LT 0.10
Thursday Night LT 0.10
Friday 0
Crystal Mt Precipitation Forecast
Wednesday Night 0.25
Thursday LT 0.25
Thursday Night LT 0.10
Friday 0
Paradise Precipitation Forecast
Wednesday Night 0.75
Thursday 0.50
Thursday Night 0.25
Friday 0
White Pass Precipitation Forecast
Wednesday Night 0.50
Thursday 0.25
Thursday Night LT 0.25
Friday 0
Mt Hood Meadows Precipitation Forecast
Wednesday Night 0.50 - 0.75
Thursday 0.25 - 0.50
Thursday Night LT 0.10
Friday 0
Timberline Precipitation Forecast
Wednesday Night 0.75
Thursday 0.25 - 0.50
Thursday Night LT 0.10
Friday 0

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Wednesday Evening WSW 10 - 20 SW 10 - 20 W 15 - 25 SW 10 - 20 W 25 - 35
Wednesday Night W 10 - 20 WSW 15 - 25 W 10 - 20 W 10 - 20 W 25 - 35
Thursday Morning WSW 10 - 20 SW 5 - 15 W 10 - 20 WSW 10 - 20 W 20 - 30
Hurricane Ridge Elevation
Wednesday Evening WSW 10 - 20
Wednesday Night W 10 - 20
Thursday Morning WSW 10 - 20
Thursday Afternoon WSW 5 - 15
Mt. Baker Elevation
Wednesday Evening SW 10 - 20
Wednesday Night WSW 15 - 25
Thursday Morning SW 5 - 15
Thursday Afternoon WSW 5 - 15
Stevens and Snoqualmie Pass Elevation
Wednesday Evening W 15 - 25
Wednesday Night W 10 - 20
Thursday Morning W 10 - 20
Thursday Afternoon W 10 - 20
Mt. Rainier Elevation
Wednesday Evening SW 10 - 20
Wednesday Night W 10 - 20
Thursday Morning WSW 10 - 20
Thursday Afternoon WSW 10 - 20
Mt. Hood Elevation
Wednesday Evening W 25 - 35
Wednesday Night W 25 - 35
Thursday Morning W 20 - 30
Thursday Afternoon W 20 - 30
Hurricane Ridge Direction - Speed
Wednesday Evening WSW 10 - 20
Wednesday Night W 10 - 20
Thursday Morning WSW 10 - 20
Thursday Afternoon WSW 5 - 15
Mt. Baker Direction - Speed
Wednesday Evening SW 10 - 20
Wednesday Night WSW 15 - 25
Thursday Morning SW 5 - 15
Thursday Afternoon WSW 5 - 15
Stevens and Snoqualmie Pass Direction - Speed
Wednesday Evening W 15 - 25
Wednesday Night W 10 - 20
Thursday Morning W 10 - 20
Thursday Afternoon W 10 - 20
Mt. Rainier Direction - Speed
Wednesday Evening SW 10 - 20
Wednesday Night W 10 - 20
Thursday Morning WSW 10 - 20
Thursday Afternoon WSW 10 - 20
Mt. Hood Direction - Speed
Wednesday Evening W 25 - 35
Wednesday Night W 25 - 35
Thursday Morning W 20 - 30
Thursday Afternoon W 20 - 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 Evening WSW 30 - 40 WSW 35 - 45 WSW 35 - 45 WSW 35 - 45 W 45 - 60
Wednesday Night W 25 - 35 W 25 - 35 W 30 - 40 W 30 - 40 W 40 - 55
Thursday Morning W 25 - 35 W 25 - 35 W 30 - 40 W 30 - 40 W 35 - 45
Mt. Baker Direction - Speed
Wednesday Evening WSW 30 - 40
Wednesday Night W 25 - 35
Thursday Morning W 25 - 35
Thursday Afternoon W 20 - 30
Washington Pass Direction - Speed
Wednesday Evening WSW 35 - 45
Wednesday Night W 25 - 35
Thursday Morning W 25 - 35
Thursday Afternoon W 25 - 35
Stevens and Snoqualmie Pass Direction - Speed
Wednesday Evening WSW 35 - 45
Wednesday Night W 30 - 40
Thursday Morning W 30 - 40
Thursday Afternoon W 30 - 40
Mt. Rainier Direction - Speed
Wednesday Evening WSW 35 - 45
Wednesday Night W 30 - 40
Thursday Morning W 30 - 40
Thursday Afternoon W 25 - 35
Mt. Hood Direction - Speed
Wednesday Evening W 45 - 60
Wednesday Night W 40 - 55
Thursday Morning W 35 - 45
Thursday Afternoon W 30 - 40

Extended Weather Synopsis for Friday night through Sunday

Conditions look generally dry as we head into the weekend. Don't rule out an isolated shower near the Canadian border, particularly near Mt Baker, but that will be the exception rather than the rule. A weak high-pressure ridge sits over the region pushing any available moisture up into British Columbia. Look for a better chance of sunshine the further south and east you travel in the range.

An approaching storm system begins to bear down on the area by Sunday, spreading increasing clouds and eventually precipitation across the mountains. Weather models seem a bit uncertain about how much rain and snow we can expect with this system, however, snowlevels generally stay below the passes throughout the extended forecast period. 

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Friday Night Snow Level 2000' - 3000' 2000' - 3500' 2500' - 4000'
Saturday Snow Level 2500' - 3500' 2500' - 3500' 2500' - 3500' *
Saturday Night Snow Level 2000' - 3500' 2000' - 3500' 2000' - 3500' *
Mt. Baker Elevation
Friday Night Snow Level
2000' - 3000'
Saturday Snow Level
2500' - 3500'
(Easterly Flow *)
Saturday Night Snow Level
2000' - 3500'
(Easterly Flow *)
Sunday Snow Level
2000' - 3000'
(Easterly Flow *)
Snoqualmie Pass Elevation
Friday Night Snow Level
2000' - 3500'
Saturday Snow Level
2500' - 3500'
(Easterly Flow *)
Saturday Night Snow Level
2000' - 3500'
(Easterly Flow *)
Sunday Snow Level
2000' - 3000'
(Easterly Flow *)
Mt. Hood Elevation
Friday Night Snow Level
2500' - 4000'
Saturday Snow Level
2500' - 3500'
(Easterly Flow *)
Saturday Night Snow Level
2000' - 3500'
(Easterly Flow *)
Sunday Snow Level
3000' - 4000'
(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 Nov 17, 2020

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