Issued: 3:20 PM PST Tuesday, January 30, 2018
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 Tuesday & Tuesday

A broad upper trough over much of Canada has pushed south over the Pacific Northwest on Tuesday bringing much cooler and more seasonal temperatures. 

A cool and slightly unstable air mass is bringing intermittent snow showers to the Olympics and Cascades on a moderate W-SW flow. The forecast region will continue to see snow shower activity at low snow levels for the duration of Tuesday through Wednesday night with a very gradual decrease in the shower activity with time as the westerly flow begins to weaken and warmer air aloft begins working into the region making the air mass more stable as a ridge starts building offshore.

On Tuesday afternoon, moderate intensity scattered snow showers with some graupel (rimed snow) mixed in and resulting from the convection and instability. Tuesday's snowfall will continue to be low density and cold.

Snowfall totals Wednesday through Wednesday night are expected to be 8" or less at most NWAC stations with the central Cascades picking up the most snow.

Weather Forecast

Olympics
Tuesday Light snow showers.
Tuesday Night Light snow showers.
Wednesday Decreasing light snow showers.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Tuesday Light to moderate snow showers with generally higher intensities near Paradise and Mt. Baker.
Tuesday Night Generally light snow showers with higher intensities likely in convergence near Mt. Baker during the evening hours.
Wednesday Decreasing light snow showers.
East Slopes of the Washington Cascades
Tuesday Generally light snow showers.
Tuesday Night Generally light snow showers.
Wednesday Decreasing light snow showers.
Mt. Hood
Tuesday Light to moderate snow showers.
Tuesday Night Light snow showers.
Wednesday Decreasing light snow showers.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Tuesday Afternoon Snow Level 2000' 2000' 2000' ' ' 2000' ' 3000'
Tuesday Night Snow Level 1500' 1000' 1000' ' ' 1000' ' 2000'
Wednesday Morning Snow Level 1500' 1500' 1000' ' ' 2000' ' 2500'
Wednesday Afternoon Snow Level 1500' 2000' 1500' ' ' 2500' ' 3000'
Hurricane Ridge Elevation
Tuesday Afternoon Snow Level
2000'
Tuesday Night Snow Level
1500'
Wednesday Morning Snow Level
1500'
Wednesday Afternoon Snow Level
1500'
Wednesday Night Snow Level
3000'
Mt. Baker Elevation
Tuesday Afternoon Snow Level
2000'
Tuesday Night Snow Level
1000'
Wednesday Morning Snow Level
1500'
Wednesday Afternoon Snow Level
2000'
Wednesday Night Snow Level
2000'
Washington Pass Elevation
Tuesday Afternoon Snow Level
2000'
Tuesday Night Snow Level
1000'
Wednesday Morning Snow Level
1000'
Wednesday Afternoon Snow Level
1500'
Wednesday Night Snow Level
1500'
Leavenworth Elevation
Tuesday Afternoon Snow Level
'
Tuesday Night Snow Level
'
Wednesday Morning Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Stevens Pass Elevation
Tuesday Afternoon Snow Level
'
Tuesday Night Snow Level
'
Wednesday Morning Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Snoqualmie Pass Elevation
Tuesday Afternoon Snow Level
2000'
Tuesday Night Snow Level
1000'
Wednesday Morning Snow Level
2000'
Wednesday Afternoon Snow Level
2500'
Wednesday Night Snow Level
2500'
Mt. Rainier & Crystal Elevation
Tuesday Afternoon Snow Level
'
Tuesday Night Snow Level
'
Wednesday Morning Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Mt. Hood Elevation
Tuesday Afternoon Snow Level
3000'
Tuesday Night Snow Level
2000'
Wednesday Morning Snow Level
2500'
Wednesday Afternoon Snow Level
3000'
Wednesday Night Snow Level
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.

Precipitation Forecast

Tuesday Tuesday
Hurricane Ridge 0 - 0.50 LT 0.25
Mt Baker Ski Area 0 - 0.75 LT 0.25
Washington Pass 0 - 0.50 LT 0.25
Stevens Pass LT 0.25 0 - 0.50
Snoqualmie Pass 0 - 0.50 0 - 0.50
Mission Ridge LT 0.10 LT 0.10
Crystal Mt 0.50 - 0.75 LT 0.25
Paradise 0 - 0.75 0.25 - 0.50
White Pass 0 - 0.50 LT 0.25
Mt Hood Meadows 0 - 0.75 LT 0.25
0.75 - 1.00 LT 0.25

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Tuesday Afternoon WSW 15 - 25 WSW 15 - 25 WSW 25 - 35 --- - WSW 20 - 30
Tuesday Night WSW 15 - 25 WSW 10 - 20 WSW 20 - 30 --- - WSW 20 - 30
Wednesday Morning WSW 10 - 20 WSW 5 - 15 WSW 10 - 20 --- - WSW 10 - 20
Wednesday Afternoon SW 15 - 25 SW 5 - 15 WSW 20 - 30 --- - WSW 10 - 20
Hurricane Ridge Elevation
Tuesday Afternoon WSW 15 - 25
Tuesday Night WSW 15 - 25
Wednesday Morning WSW 10 - 20
Wednesday Afternoon SW 15 - 25
Wednesday Night WSW 10 - 20
Mt. Baker Elevation
Tuesday Afternoon WSW 15 - 25
Tuesday Night WSW 10 - 20
Wednesday Morning WSW 5 - 15
Wednesday Afternoon SW 5 - 15
Wednesday Night WSW 10 - 20
Stevens and Snoqualmie Pass Elevation
Tuesday Afternoon WSW 25 - 35
Tuesday Night WSW 20 - 30
Wednesday Morning WSW 10 - 20
Wednesday Afternoon WSW 20 - 30
Wednesday Night WSW 5 - 15
Mt. Rainier Elevation
Tuesday Afternoon --- -
Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night --- -
Mt. Hood Elevation
Tuesday Afternoon WSW 20 - 30
Tuesday Night WSW 20 - 30
Wednesday Morning WSW 10 - 20
Wednesday Afternoon WSW 10 - 20
Wednesday Night WSW 5 - 15
Hurricane Ridge Direction - Speed
Tuesday Afternoon WSW 15 - 25
Tuesday Night WSW 15 - 25
Wednesday Morning WSW 10 - 20
Wednesday Afternoon SW 15 - 25
Wednesday Night WSW 10 - 20
Mt. Baker Direction - Speed
Tuesday Afternoon WSW 15 - 25
Tuesday Night WSW 10 - 20
Wednesday Morning WSW 5 - 15
Wednesday Afternoon SW 5 - 15
Wednesday Night WSW 10 - 20
Stevens and Snoqualmie Pass Direction - Speed
Tuesday Afternoon WSW 25 - 35
Tuesday Night WSW 20 - 30
Wednesday Morning WSW 10 - 20
Wednesday Afternoon WSW 20 - 30
Wednesday Night WSW 5 - 15
Mt. Rainier Direction - Speed
Tuesday Afternoon --- -
Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night --- -
Mt. Hood Direction - Speed
Tuesday Afternoon WSW 20 - 30
Tuesday Night WSW 20 - 30
Wednesday Morning WSW 10 - 20
Wednesday Afternoon WSW 10 - 20
Wednesday Night WSW 5 - 15

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
Tuesday Afternoon WSW 30 - 40 WSW 35 - 50 WSW 40 - 60 --- - WSW 35 - 50
Tuesday Night WSW 25 - 35 WSW 25 - 35 W 35 - 50 --- - W 35 - 50
Wednesday Morning W 20 - 30 W 20 - 30 W 20 - 30 --- - W 30 - 40
Wednesday Afternoon WSW 25 - 35 WSW 20 - 30 WSW 25 - 35 --- - WSW 40 - 60
Mt. Baker Direction - Speed
Tuesday Afternoon WSW 30 - 40
Tuesday Night WSW 25 - 35
Wednesday Morning W 20 - 30
Wednesday Afternoon WSW 25 - 35
Wednesday Night WSW 20 - 30
Washington Pass Direction - Speed
Tuesday Afternoon WSW 35 - 50
Tuesday Night WSW 25 - 35
Wednesday Morning W 20 - 30
Wednesday Afternoon WSW 20 - 30
Wednesday Night WSW 25 - 35
Stevens and Snoqualmie Pass Direction - Speed
Tuesday Afternoon WSW 40 - 60
Tuesday Night W 35 - 50
Wednesday Morning W 20 - 30
Wednesday Afternoon WSW 25 - 35
Wednesday Night WSW 25 - 35
Mt. Rainier Direction - Speed
Tuesday Afternoon --- -
Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night --- -
Mt. Hood Direction - Speed
Tuesday Afternoon WSW 35 - 50
Tuesday Night W 35 - 50
Wednesday Morning W 30 - 40
Wednesday Afternoon WSW 40 - 60
Wednesday Night WSW 20 - 30

Extended Weather Synopsis for Tuesday night through Tuesday

A ridge will continue to build offshore Thursday through Saturday, bringing warming to the Pacific Northwest, with particularly strong warming expected Thursday through Friday. The Pacific Northwest will remain downstream of the ridge with a series of shortwave systems running over the top of the ridge.

The first of these systems arrives on Thursday and will bring a warm front and significant warming across the region as it lifts northward. A shortwave trough will bring some cooling and strong westerly crest-level winds on Friday with a gradual warming into Saturday and sustained moderate W or W-NW flow at crest level. Stay tuned to the forecast because the models don't predict the strength and timing of these shortwave systems very well 4-5 days in advance.

Extended Weather

Olympics, Washington Cascades and Mt. Hood Area
Thursday Light rain and snow becoming light to moderate. Strong warming with southerly flow, initially in the south and then in the north later in the day into the overnight hours. Rain and snow becoming moderate to heavy overnight, particularly in the central cascades south to Mt. Hood as westerly flow becomes moderate to strong at crest level. Friday Light rain and snow with pulses of moderate to heavy rain and snow and moderate W and W-NW winds. Snow levels lowering slightly later Friday. Similar conditions are expected Friday night. Saturday Moderate to strong westerly flow with periods of moderate to occasionally heavy rain and high elevation snow continue. Elsewhere, generally light rain/snow.

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Thursday Snow Level 2000' - 3000' 3000' - 4000' 5000' - 7000'
Thursday Night Snow Level 3500' - 4500' 5500' - 7500' 7500' - 8500'
Friday Snow Level 4400' - 5500' 5000' - 6000' 6500' - 8500'
Friday Night Snow Level 4000' - 5000' 4000' - 5000' 7000' - 8000'
Mt. Baker Elevation
Thursday Snow Level
2000' - 3000'
Thursday Night Snow Level
3500' - 4500'
Friday Snow Level
4400' - 5500'
Friday Night Snow Level
4000' - 5000'
Saturday Snow Level
4500' - 5500'
Snoqualmie Pass Elevation
Thursday Snow Level
3000' - 4000'
Thursday Night Snow Level
5500' - 7500'
Friday Snow Level
5000' - 6000'
Friday Night Snow Level
4000' - 5000'
Saturday Snow Level
6000' - 7000'
Mt. Hood Elevation
Thursday Snow Level
5000' - 7000'
Thursday Night Snow Level
7500' - 8500'
Friday Snow Level
6500' - 8500'
Friday Night Snow Level
7000' - 8000'
Saturday Snow Level
7000' - 8000'

* 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 Jan 30, 2018

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.