Issued: 1:57 PM PST Monday, November 30, 2020
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 Monday night through Thursday

Post frontal showers are winding down across many areas this afternoon with the heaviest showers focused from the Canadian border down to Hwy 2 West. Outside of the Olympics and Mt Baker area, westerly winds remain quite strong this afternoon. Roughly 6-10" of inches of new snow accumulated today above 3000' with locally higher amounts in the Mt Baker area where likely a foot or more has accumulated. Some weather stations may under-report new snowfall where there's been significant wind.   

Showers will become more scattered and eventually peter out later this evening along the west slopes of the Cascades as strong upper level ridging builds offshore. Winds will also decrease overnight, staying elevated along the higher terrain of the east-central slopes of the Cascades and Mt Hood. 

Areas of low clouds banked along the west slopes of the Cascades Monday night should give way to clear and sunny skies Tuesday. Strong surface high pressure in southern British Columbia will begin sliding into the inland NW Tuesday, setting the stage for a period of strong offshore flow.  Look for warm air associated with the upper level ridge to make the most inroads over the Olympics and upper slopes on Mt Hood Tuesday afternoon. 

Strong offshore flow featuring moderate to locally strong east winds will develop in the Passes Tuesday night through Wednesday. East winds will likely reach up to Cascade crest level and impact the usual suspects like Paradise, Crystal and the east side of Mt. Hood. Along with the offshore flow comes a strong cross-Cascade temperature gradient with much warmer air over western Washington and Oregon and cooler air on the east side of the mountains. Wednesday will be a mixed bag of freezing levels and temperatures. For areas under the influence of temperature inversions, expect cooler temperatures on lower lopes and milder temperatures for upper slopes. 

Weather Forecast

Hurricane Ridge
Monday Night Partly cloudy with a chance of showers in the evening.
Mt. Baker
Monday Night Mostly cloudy. Scattered light snow showers in the evening ending after midnight.
Washington Pass and Leavenworth
Monday Night Mostly cloudy in the evening becoming partly cloudy overnight. Scattered light snow showers in the evening ending after midnight.
Stevens and Snoqualmie Pass
Monday Night Mostly cloudy. Scattered light snow showers in the evening ending after midnight. Moderate west winds at Pass level becoming light overnight.
Mt. Rainier, Crystal and White Pass
Monday Night Mostly cloudy. Scattered light snow showers in the evening ending after midnight.
Mt. Hood
Monday Night Mostly cloudy. Scattered light snow showers in the evening ending after midnight.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Monday Evening Snow Level 2000' 2000' 1500' 2000' 2000' 2000' 2000' 2500'
Monday Night Snow Level 1500' 1000' 0' 1000' 1000' 1500' 1500' 2000'
Tuesday Morning Freezing Level 3000' 1500' 1500' 2500' 2500' 2500' 3000' 3000'
Tuesday Afternoon Freezing Level * 6000' 4000' 3500' 3500' 3500' 3500' 5000' 7500'
Tuesday Evening Freezing Level * 7500' 7000' 2500' 3000' 3000' 3500' 7000' 8000'
Tuesday Night Freezing Level * 9500' 9500' 2000' 3000' 3000' 5000' 9000' 9000'
Wednesday Morning Freezing Level * 10000' 9500' 4000' 5000' 5500' 8000' 10000' 12000'
Hurricane Ridge Elevation
Monday Evening Snow Level
2000'
Monday Night Snow Level
1500'
Tuesday Morning Freezing Level
3000'
Tuesday Afternoon Freezing Level
6000'
(Easterly Flow *)
Tuesday Evening Freezing Level
7500'
(Easterly Flow *)
Tuesday Night Freezing Level
9500'
(Easterly Flow *)
Wednesday Morning Freezing Level
10000'
(Easterly Flow *)
Wednesday Afternoon Freezing Level
10000'
(Easterly Flow *)
Mt. Baker Elevation
Monday Evening Snow Level
2000'
Monday Night Snow Level
1000'
Tuesday Morning Freezing Level
1500'
Tuesday Afternoon Freezing Level
4000'
(Easterly Flow *)
Tuesday Evening Freezing Level
7000'
(Easterly Flow *)
Tuesday Night Freezing Level
9500'
(Easterly Flow *)
Wednesday Morning Freezing Level
9500'
(Easterly Flow *)
Wednesday Afternoon Freezing Level
9500'
(Easterly Flow *)
Washington Pass Elevation
Monday Evening Snow Level
1500'
Monday Night Snow Level
0'
Tuesday Morning Freezing Level
1500'
Tuesday Afternoon Freezing Level
3500'
(Easterly Flow *)
Tuesday Evening Freezing Level
2500'
(Easterly Flow *)
Tuesday Night Freezing Level
2000'
(Easterly Flow *)
Wednesday Morning Freezing Level
4000'
(Easterly Flow *)
Wednesday Afternoon Freezing Level
4000'
(Easterly Flow *)
Leavenworth Elevation
Monday Evening Snow Level
2000'
Monday Night Snow Level
1000'
Tuesday Morning Freezing Level
2500'
Tuesday Afternoon Freezing Level
3500'
(Easterly Flow *)
Tuesday Evening Freezing Level
3000'
(Easterly Flow *)
Tuesday Night Freezing Level
3000'
(Easterly Flow *)
Wednesday Morning Freezing Level
5000'
(Easterly Flow *)
Wednesday Afternoon Freezing Level
5000'
(Easterly Flow *)
Stevens Pass Elevation
Monday Evening Snow Level
2000'
Monday Night Snow Level
1000'
Tuesday Morning Freezing Level
2500'
Tuesday Afternoon Freezing Level
3500'
(Easterly Flow *)
Tuesday Evening Freezing Level
3000'
(Easterly Flow *)
Tuesday Night Freezing Level
3000'
(Easterly Flow *)
Wednesday Morning Freezing Level
5500'
(Easterly Flow *)
Wednesday Afternoon Freezing Level
5500'
(Easterly Flow *)
Snoqualmie Pass Elevation
Monday Evening Snow Level
2000'
Monday Night Snow Level
1500'
Tuesday Morning Freezing Level
2500'
Tuesday Afternoon Freezing Level
3500'
(Easterly Flow *)
Tuesday Evening Freezing Level
3500'
(Easterly Flow *)
Tuesday Night Freezing Level
5000'
(Easterly Flow *)
Wednesday Morning Freezing Level
8000'
(Easterly Flow *)
Wednesday Afternoon Freezing Level
8000'
(Easterly Flow *)
Mt. Rainier & Crystal Elevation
Monday Evening Snow Level
2000'
Monday Night Snow Level
1500'
Tuesday Morning Freezing Level
3000'
Tuesday Afternoon Freezing Level
5000'
(Easterly Flow *)
Tuesday Evening Freezing Level
7000'
(Easterly Flow *)
Tuesday Night Freezing Level
9000'
(Easterly Flow *)
Wednesday Morning Freezing Level
10000'
(Easterly Flow *)
Wednesday Afternoon Freezing Level
10000'
(Easterly Flow *)
Mt. Hood Elevation
Monday Evening Snow Level
2500'
Monday Night Snow Level
2000'
Tuesday Morning Freezing Level
3000'
Tuesday Afternoon Freezing Level
7500'
(Easterly Flow *)
Tuesday Evening Freezing Level
8000'
(Easterly Flow *)
Tuesday Night Freezing Level
9000'
(Easterly Flow *)
Wednesday Morning Freezing Level
12000'
(Easterly Flow *)
Wednesday Afternoon Freezing Level
12000'
(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

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

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Monday Evening WNW 10 - 20 WNW 5 - 15 NW 15 - 25 NW 10 - 20 WNW 20 - 30
Monday Night W 5 - 15 W 0 - 10 NW 10 - 20 NW 5 - 15 NW 10 - 20
Tuesday Morning NW 0 - 10 VAR 0 - 10 WNW 5 - 15 VAR 0 - 10 VAR 0 - 10
Hurricane Ridge Elevation
Monday Evening WNW 10 - 20
Monday Night W 5 - 15
Tuesday Morning NW 0 - 10
Tuesday Afternoon NE 0 - 10
Mt. Baker Elevation
Monday Evening WNW 5 - 15
Monday Night W 0 - 10
Tuesday Morning VAR 0 - 10
Tuesday Afternoon E 0 - 10
Stevens and Snoqualmie Pass Elevation
Monday Evening NW 15 - 25
Monday Night NW 10 - 20
Tuesday Morning WNW 5 - 15
Tuesday Afternoon ESE 10 - 20
Mt. Rainier Elevation
Monday Evening NW 10 - 20
Monday Night NW 5 - 15
Tuesday Morning VAR 0 - 10
Tuesday Afternoon E 0 - 10
Mt. Hood Elevation
Monday Evening WNW 20 - 30
Monday Night NW 10 - 20
Tuesday Morning VAR 0 - 10
Tuesday Afternoon ESE 10 - 20
Hurricane Ridge Direction - Speed
Monday Evening WNW 10 - 20
Monday Night W 5 - 15
Tuesday Morning NW 0 - 10
Tuesday Afternoon NE 0 - 10
Mt. Baker Direction - Speed
Monday Evening WNW 5 - 15
Monday Night W 0 - 10
Tuesday Morning VAR 0 - 10
Tuesday Afternoon E 0 - 10
Stevens and Snoqualmie Pass Direction - Speed
Monday Evening NW 15 - 25
Monday Night NW 10 - 20
Tuesday Morning WNW 5 - 15
Tuesday Afternoon ESE 10 - 20
Mt. Rainier Direction - Speed
Monday Evening NW 10 - 20
Monday Night NW 5 - 15
Tuesday Morning VAR 0 - 10
Tuesday Afternoon E 0 - 10
Mt. Hood Direction - Speed
Monday Evening WNW 20 - 30
Monday Night NW 10 - 20
Tuesday Morning VAR 0 - 10
Tuesday Afternoon ESE 10 - 20

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
Monday Evening NW 20 - 30 NW 30 - 40 NW 40 - 50 NW 40 - 50 NW 40 - 50
Monday Night NW 15 - 25 NW 10 - 20 NW 20 - 30 NW 15 - 25 NW 20 - 30
Tuesday Morning NW 10 - 20 NW 5 - 15 NW 15 - 25 NW 10 - 20 NW 10 - 20
Mt. Baker Direction - Speed
Monday Evening NW 20 - 30
Monday Night NW 15 - 25
Tuesday Morning NW 10 - 20
Tuesday Afternoon NE 5 - 15
Washington Pass Direction - Speed
Monday Evening NW 30 - 40
Monday Night NW 10 - 20
Tuesday Morning NW 5 - 15
Tuesday Afternoon NE 10 - 20
Stevens and Snoqualmie Pass Direction - Speed
Monday Evening NW 40 - 50
Monday Night NW 20 - 30
Tuesday Morning NW 15 - 25
Tuesday Afternoon NE 5 - 15
Mt. Rainier Direction - Speed
Monday Evening NW 40 - 50
Monday Night NW 15 - 25
Tuesday Morning NW 10 - 20
Tuesday Afternoon ENE 5 - 15
Mt. Hood Direction - Speed
Monday Evening NW 40 - 50
Monday Night NW 20 - 30
Tuesday Morning NW 10 - 20
Tuesday Afternoon N 0 - 10

Extended Weather Synopsis for Thursday night through Thursday

The aforementioned pattern will continue through the end of the work week.  A splitting frontal system offshore on Thursday looks unlikely to bring any weather into the area as it runs into the ridge. Cold air will begin to moderate on the east side of the Cascades by the end of the week and the common 10,000-12,000 ft freezing levels seen to the west should become more widespread across the region by Thursday and Friday.  

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Wednesday Night Freezing Level 8500' - 9500' 9000' - 10000' 11000' - 12000' *
Thursday Freezing Level 8500' - 9500' 9000' - 10000' 11000' - 12000' *
Thursday Night Freezing Level 8500' - 9500' 9000' - 10000' 11000' - 12000' *
Mt. Baker Elevation
Wednesday Night Freezing Level
8500' - 9500'
(Easterly Flow *)
Thursday Freezing Level
8500' - 9500'
(Easterly Flow *)
Thursday Night Freezing Level
8500' - 9500'
(Easterly Flow *)
Friday Freezing Level
9000' - 10000'
(Easterly Flow *)
Snoqualmie Pass Elevation
Wednesday Night Freezing Level
9000' - 10000'
(Easterly Flow *)
Thursday Freezing Level
9000' - 10000'
(Easterly Flow *)
Thursday Night Freezing Level
9000' - 10000'
(Easterly Flow *)
Friday Freezing Level
10000' - 11000'
(Easterly Flow *)
Mt. Hood Elevation
Wednesday Night Freezing Level
11000' - 12000'
(Easterly Flow *)
Thursday Freezing Level
11000' - 12000'
(Easterly Flow *)
Thursday Night Freezing Level
11000' - 12000'
(Easterly Flow *)
Friday Freezing Level
12000' - 13000'
(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 30, 2020

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