Issued: 2:17 PM PST Sunday, November 15, 2020
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 Sunday night through Tuesday

A very active weather pattern continues. In the wake of Sunday morning's frontal system, moderate westerly winds continue to provide enough instability and moisture for accumulating rain and snow. These rain and snow showers should decrease overnight as the atmosphere stabilizes ahead of our next system, a strengthening and deep low moving northward offshore toward the northern tip of Vancouver Island. The strong leading warm front moving northward over Oregon should bring a rapid rise in snow levels and rapidly increasing winds to the Mt. Hood area.

The warm front will cross the NWAC forecast region from south to north during the day on Monday, bringing a period of moderate to strong ESE winds shifting more S or SSW behind the front, along with a period of moderate to heavy rain/snow. As the front lifts northward, the precipitation should cut off, but 4-6" of snowfall are possible for many areas above 4000 ft before a shift to rain in most areas (except the highest elevations). The precipitation exits north into Canada by late Monday evening. The warm sector of the storm remains over the region with mostly cloudy and very mild conditions into Tuesday morning, with snow levels peaking at 8000 ft in the north and 11000 ft in the south.

The associated cold front comes barreling into the region mid-Tuesday morning, with moderate to strong southerly winds, particularly in areas exposed to this wind direction, such as the Mt. Baker area and Olympics. Expect 0.25-0.75" of rain, turning to rain and snow behind the front on Tuesday afternoon as snow levels lower.

Weather Forecast

Hurricane Ridge
Sunday Night Isolated light rain and snow showers in the evening, then becoming mostly cloudy. Light to moderate winds becoming light.
Mt. Baker
Sunday Night Decreasing light rain and snow showers in the evening, ending by midnight, then cloudy conditions after midnight. Light to moderate winds early, becoming light.
Washington Pass and Leavenworth
Sunday Night Decreasing light rain and snow showers near the Cascade Crest in the evening, ending by midnight, then cloudy conditions after midnight. Light to moderate winds early, becoming light.
Stevens and Snoqualmie Pass
Sunday Night Decreasing light rain and snow showers; a mix of rain and snow at Snoqualmie Pass level and generally snow at Stevens Pass level. Moderate 5000 ft winds early, becoming light. Light W pass-level winds shifting to light E winds in the early morning hours.
Mt. Rainier, Crystal and White Pass
Sunday Night Decreasing moderate rain and snow showers at Paradise; decreasing light rain and snow showers at Crystal and White Pass. Light 5000 ft winds becoming moderate to strong.
Mt. Hood
Sunday Night Very light snow showers in the evening, with increasing light snow in the early morning hours becoming moderate by morning. Very rapidly rising snow levels. Light to moderate 5000 ft winds becoming moderate to strong.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Sunday Evening Snow Level 3500' 3000' 3000' 4000' 3500' 3500' 4000' 4500'
Sunday Night Snow Level * 3500' 3000' 2500' 3500' 3500' 3500' 4000' 5000'
Monday Morning Snow Level * 4000' 3000' 2500' 3000' 3500' 4000' 4000' 6500'
Monday Afternoon Snow Level * 4500' 3500' 3500' 3000' 3500' 4500' 4500' 8500'
Monday Evening Snow Level * 8500' 5000' 3500' 5500' 5500' 8000' 9000' 10000'
Monday Night Snow Level * 9500' 8500' 6500' 9000' 8500' 9500' 10000' 11000'
Tuesday Morning Snow Level * 9000' 9500' 8000' 9000' 9500' 10500' 10000' 10500'
Hurricane Ridge Elevation
Sunday Evening Snow Level
3500'
Sunday Night Snow Level
3500'
(Easterly Flow *)
Monday Morning Snow Level
4000'
(Easterly Flow *)
Monday Afternoon Snow Level
4500'
(Easterly Flow *)
Monday Evening Snow Level
8500'
(Easterly Flow *)
Monday Night Snow Level
9500'
(Easterly Flow *)
Tuesday Morning Snow Level
9000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
6000'
(Easterly Flow *)
Mt. Baker Elevation
Sunday Evening Snow Level
3000'
Sunday Night Snow Level
3000'
(Easterly Flow *)
Monday Morning Snow Level
3000'
(Easterly Flow *)
Monday Afternoon Snow Level
3500'
(Easterly Flow *)
Monday Evening Snow Level
5000'
(Easterly Flow *)
Monday Night Snow Level
8500'
(Easterly Flow *)
Tuesday Morning Snow Level
9500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
6000'
(Easterly Flow *)
Washington Pass Elevation
Sunday Evening Snow Level
3000'
Sunday Night Snow Level
2500'
(Easterly Flow *)
Monday Morning Snow Level
2500'
(Easterly Flow *)
Monday Afternoon Snow Level
3500'
(Easterly Flow *)
Monday Evening Snow Level
3500'
(Easterly Flow *)
Monday Night Snow Level
6500'
(Easterly Flow *)
Tuesday Morning Snow Level
8000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
6000'
(Easterly Flow *)
Leavenworth Elevation
Sunday Evening Snow Level
4000'
Sunday Night Snow Level
3500'
(Easterly Flow *)
Monday Morning Snow Level
3000'
(Easterly Flow *)
Monday Afternoon Snow Level
3000'
(Easterly Flow *)
Monday Evening Snow Level
5500'
(Easterly Flow *)
Monday Night Snow Level
9000'
(Easterly Flow *)
Tuesday Morning Snow Level
9000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
6000'
(Easterly Flow *)
Stevens Pass Elevation
Sunday Evening Snow Level
3500'
Sunday Night Snow Level
3500'
(Easterly Flow *)
Monday Morning Snow Level
3500'
(Easterly Flow *)
Monday Afternoon Snow Level
3500'
(Easterly Flow *)
Monday Evening Snow Level
5500'
(Easterly Flow *)
Monday Night Snow Level
8500'
(Easterly Flow *)
Tuesday Morning Snow Level
9500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
5500'
(Easterly Flow *)
Snoqualmie Pass Elevation
Sunday Evening Snow Level
3500'
Sunday Night Snow Level
3500'
(Easterly Flow *)
Monday Morning Snow Level
4000'
(Easterly Flow *)
Monday Afternoon Snow Level
4500'
(Easterly Flow *)
Monday Evening Snow Level
8000'
(Easterly Flow *)
Monday Night Snow Level
9500'
(Easterly Flow *)
Tuesday Morning Snow Level
10500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
6000'
(Easterly Flow *)
Mt. Rainier & Crystal Elevation
Sunday Evening Snow Level
4000'
Sunday Night Snow Level
4000'
(Easterly Flow *)
Monday Morning Snow Level
4000'
(Easterly Flow *)
Monday Afternoon Snow Level
4500'
(Easterly Flow *)
Monday Evening Snow Level
9000'
(Easterly Flow *)
Monday Night Snow Level
10000'
(Easterly Flow *)
Tuesday Morning Snow Level
10000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
5500'
(Easterly Flow *)
Mt. Hood Elevation
Sunday Evening Snow Level
4500'
Sunday Night Snow Level
5000'
(Easterly Flow *)
Monday Morning Snow Level
6500'
(Easterly Flow *)
Monday Afternoon Snow Level
8500'
(Easterly Flow *)
Monday Evening Snow Level
10000'
(Easterly Flow *)
Monday Night Snow Level
11000'
(Easterly Flow *)
Tuesday Morning Snow Level
10500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
6500'
(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

Sunday Night Monday Monday Night Tuesday
4 pm - 4 am 4 am - 4 pm 4 pm - 4 am 4 am - 4 pm
Hurricane Ridge LT 0.10 0.50 0.25 0.25 - 0.50
Mt Baker Ski Area LT 0.10 0.25 - 0.50 1.00 0.50
Washington Pass LT 0.25 0.25 - 0.50 0.25 - 0.50 LT 0.25
Leavenworth LT 0.10 0.25 LT 0.10 LT 0.10
Stevens Pass 0.25 0.25 - 0.50 LT 0.10 LT 0.25
Snoqualmie Pass LT 0.25 0.25 - 0.50 0 LT 0.25
Mission Ridge LT 0.10 0.25 - 0.50 0 LT 0.10
Crystal Mt LT 0.10 5.00 - 6.00 0 0.50
Paradise 0.50 0.75 -1.00 LT 0.10 0.75
White Pass 0.25 0.25 - 0.50 0 0.25
Mt Hood Meadows 0.25 0.50 0 0.50
0.25 0.50 - 0.75 0 0.50 - 0.75
Hurricane Ridge Precipitation Forecast
Sunday Night LT 0.10
Monday 0.50
Monday Night 0.25
Tuesday 0.25 - 0.50
Mt Baker Ski Area Precipitation Forecast
Sunday Night LT 0.10
Monday 0.25 - 0.50
Monday Night 1.00
Tuesday 0.50
Washington Pass Precipitation Forecast
Sunday Night LT 0.25
Monday 0.25 - 0.50
Monday Night 0.25 - 0.50
Tuesday LT 0.25
Leavenworth Precipitation Forecast
Sunday Night LT 0.10
Monday 0.25
Monday Night LT 0.10
Tuesday LT 0.10
Stevens Pass Precipitation Forecast
Sunday Night 0.25
Monday 0.25 - 0.50
Monday Night LT 0.10
Tuesday LT 0.25
Snoqualmie Pass Precipitation Forecast
Sunday Night LT 0.25
Monday 0.25 - 0.50
Monday Night 0
Tuesday LT 0.25
Mission Ridge Precipitation Forecast
Sunday Night LT 0.10
Monday 0.25 - 0.50
Monday Night 0
Tuesday LT 0.10
Crystal Mt Precipitation Forecast
Sunday Night LT 0.10
Monday 5.00 - 6.00
Monday Night 0
Tuesday 0.50
Paradise Precipitation Forecast
Sunday Night 0.50
Monday 0.75 -1.00
Monday Night LT 0.10
Tuesday 0.75
White Pass Precipitation Forecast
Sunday Night 0.25
Monday 0.25 - 0.50
Monday Night 0
Tuesday 0.25
Mt Hood Meadows Precipitation Forecast
Sunday Night 0.25
Monday 0.50
Monday Night 0
Tuesday 0.50
Timberline Precipitation Forecast
Sunday Night 0.25
Monday 0.50 - 0.75
Monday Night 0
Tuesday 0.50 - 0.75

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Sunday Evening SW 10 - 20 SW 10 - 20 WSW 15 - 25 SW 10 - 20 WSW 15 - 25
Sunday Night SSW 5 - 15 SSW 5 - 15 SSW 5 - 15 S 5 - 15 SSW 5 - 15
Monday Morning ESE 10 - 20 ESE 5 - 15 ESE 5 - 15 ESE 10 - 20 SSW 30 - 45
Hurricane Ridge Elevation
Sunday Evening SW 10 - 20
Sunday Night SSW 5 - 15
Monday Morning ESE 10 - 20
Monday Afternoon SSE 30 - 40
Mt. Baker Elevation
Sunday Evening SW 10 - 20
Sunday Night SSW 5 - 15
Monday Morning ESE 5 - 15
Monday Afternoon ESE 20 - 30
Stevens and Snoqualmie Pass Elevation
Sunday Evening WSW 15 - 25
Sunday Night SSW 5 - 15
Monday Morning ESE 5 - 15
Monday Afternoon ESE 25 - 35
Mt. Rainier Elevation
Sunday Evening SW 10 - 20
Sunday Night S 5 - 15
Monday Morning ESE 10 - 20
Monday Afternoon SSW 25 - 35
Mt. Hood Elevation
Sunday Evening WSW 15 - 25
Sunday Night SSW 5 - 15
Monday Morning SSW 30 - 45
Monday Afternoon SSW 20 - 30
Hurricane Ridge Direction - Speed
Sunday Evening SW 10 - 20
Sunday Night SSW 5 - 15
Monday Morning ESE 10 - 20
Monday Afternoon SSE 30 - 40
Mt. Baker Direction - Speed
Sunday Evening SW 10 - 20
Sunday Night SSW 5 - 15
Monday Morning ESE 5 - 15
Monday Afternoon ESE 20 - 30
Stevens and Snoqualmie Pass Direction - Speed
Sunday Evening WSW 15 - 25
Sunday Night SSW 5 - 15
Monday Morning ESE 5 - 15
Monday Afternoon ESE 25 - 35
Mt. Rainier Direction - Speed
Sunday Evening SW 10 - 20
Sunday Night S 5 - 15
Monday Morning ESE 10 - 20
Monday Afternoon SSW 25 - 35
Mt. Hood Direction - Speed
Sunday Evening WSW 15 - 25
Sunday Night SSW 5 - 15
Monday Morning SSW 30 - 45
Monday Afternoon SSW 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
Sunday Evening WSW 30 - 40 WSW 30 - 40 WSW 35 - 45 WSW 25 - 35 WSW 30 - 40
Sunday Night WSW 15 - 25 WSW 20 - 30 WSW 30 - 40 WSW 15 - 25 WSW 35 - 50
Monday Morning SW 5 - 15 SW 5 - 15 SW 20 - 30 SW 30 - 45 WSW 35 - 50
Mt. Baker Direction - Speed
Sunday Evening WSW 30 - 40
Sunday Night WSW 15 - 25
Monday Morning SW 5 - 15
Monday Afternoon SSW 40 - 60
Washington Pass Direction - Speed
Sunday Evening WSW 30 - 40
Sunday Night WSW 20 - 30
Monday Morning SW 5 - 15
Monday Afternoon SSW 30 - 40
Stevens and Snoqualmie Pass Direction - Speed
Sunday Evening WSW 35 - 45
Sunday Night WSW 30 - 40
Monday Morning SW 20 - 30
Monday Afternoon SW 45 - 65
Mt. Rainier Direction - Speed
Sunday Evening WSW 25 - 35
Sunday Night WSW 15 - 25
Monday Morning SW 30 - 45
Monday Afternoon SW 40 - 55
Mt. Hood Direction - Speed
Sunday Evening WSW 30 - 40
Sunday Night WSW 35 - 50
Monday Morning WSW 35 - 50
Monday Afternoon WSW 35 - 50

Extended Weather Synopsis for Tuesday night through Thursday

Snow should return to some ski area bases Tuesday night as a moist active SW flow continues and the broad offshore trough gradually moves in to the region through Wednesday and Wednesday night. Models indicate a more organized wave of precipitation moving through the region Wednesday morning with some heavier precipitation. The trough should be centered over the region Thursday through Friday with decreasing generally light to occasionally moderate instability showers on a westerly flow.

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Tuesday Night Snow Level 3500' - 4500' 4000' - 5000' 4500' - 5500'
Wednesday Snow Level 2500' - 3500' 3000' - 4000' 3500' - 4500'
Wednesday Night Snow Level 2000' - 3000' 2000' - 3000' 2500' - 3500'
Mt. Baker Elevation
Tuesday Night Snow Level
3500' - 4500'
Wednesday Snow Level
2500' - 3500'
Wednesday Night Snow Level
2000' - 3000'
Thursday Snow Level
2000' - 3000'
Snoqualmie Pass Elevation
Tuesday Night Snow Level
4000' - 5000'
Wednesday Snow Level
3000' - 4000'
Wednesday Night Snow Level
2000' - 3000'
Thursday Snow Level
2000' - 3000'
Mt. Hood Elevation
Tuesday Night Snow Level
4500' - 5500'
Wednesday Snow Level
3500' - 4500'
Wednesday Night Snow Level
2500' - 3500'
Thursday Snow Level
2000' - 3000'

* 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 14, 2020

The NWAC program is administered by the USDA-Forest Service and operates from the National Weather Service Forecast Office in Seattle. NWAC services are made possible by important collaboration and support from a wide variety of federal, state and private cooperators.