Issued: 7:42 AM PST Monday, January 15, 2018
by Robert Hahn

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

Weather Synopsis for Monday & Saturday

A strong and high amplitude upper ridge has moved east of the Cascades with a ridge axis on Monday morning from Idaho into the Canadian Rockies. The ridge will provide one more day of warm temperatures as high clouds provide filtered sunlight to most areas on Monday. Overnight lows Sunday night were above freezing at all stations west of the Cascade crest. East of the Cascade crest and in the passes, overnight lows were in the upper twenties to mid-thirties with easterly winds at the passes. On Monday, inversion conditions east of the Cascade Crest should continue to keep cooler air, low clouds and fog in the forecast with moderate easterly winds bringing the cooler air through the passes.

On Monday night, a weakening cold front will arrive around midnight in the Olympics and in the early morning hours along the Cascades bringing a brief period of light to moderate precipitation. The cold front should moderate the airmass from the unseasonal warmth we've seen with the high pressure system.

On Tuesday, in the wake of the weakening cold front, an associated upper trough will bring light rain and snow showers, mainly to the Cascade west slopes and Olympics. The trough lifts northward as it progresses eastward, allowing warmer air to work into the forecast zones and reducing instability, generally cutting off precipitation from south to north on Tuesday afternoon.

Tuesday night should feature fair weather and increasing high clouds as a stronger frontal system will be approaching the Pacific Northwest coastal waters.

Weather Forecast

Olympics
Monday Filtered sunlight with high clouds and warm temperatures. Clouds thickening and lowering in the afternoon.
Monday Night Periods of light and occasionally moderate rain or snow, mainly after midnight. Snow line lowering overnight. Windy.
Tuesday Light rain and snow showers, ending late in the day.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Monday High clouds bringing filtered sunshine with cloud cover increasing in the afternoon. Low clouds and cooler with inversion conditions at the passes.
Monday Night Increasing clouds with light to moderate rain and snow in the early morning hours.
Tuesday Light rain and snow showers, mainly volcanoes and North Cascades. Becoming mostly cloudy in the afternoon.
East Slopes of the Washington Cascades
Monday Filtered sunshine with high clouds; low clouds and cooler with inversion conditions at low elevations.
Monday Night Clouds lowering with light rain or high elevation snow in the early morning hours. Possible wintry mix in some deeper valleys.
Tuesday Cloudy in the morning with isolated rain and snow showers in the north, mainly high elevations; becoming partly sunny in the south and mostly cloudy in the north by the afternoon.
Mt. Hood
Monday High clouds bringing filtered sunshine with cloud cover increasing in the afternoon.
Monday Night Light rain or snow after midnight. Snow line lowering overnight.
Tuesday Light rain and snow showers decreasing or ending in the afternoon.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Monday Morning Freezing Level * 10000' 10000' 10500' ' ' 10500' ' 10000'
Monday Afternoon Freezing Level * 9000' 10000' 10000' ' ' 10000' ' 9500'
Monday Night Snow Level * 5000' 5500' 5000' ' ' 5500' ' 5500'
Tuesday Morning Snow Level * 3500' 4000' 4000' ' ' 4000' ' 4000'
Tuesday Afternoon Snow Level * 3500' 3500' 3500' ' ' 3500' ' 4000'
Hurricane Ridge Elevation
Monday Morning Freezing Level
10000'
(Easterly Flow *)
Monday Afternoon Freezing Level
9000'
(Easterly Flow *)
Monday Night Snow Level
5000'
(Easterly Flow *)
Tuesday Morning Snow Level
3500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
3500'
(Easterly Flow *)
Tuesday Night Snow Level
4500'
(Easterly Flow *)
Mt. Baker Elevation
Monday Morning Freezing Level
10000'
(Easterly Flow *)
Monday Afternoon Freezing Level
10000'
(Easterly Flow *)
Monday Night Snow Level
5500'
(Easterly Flow *)
Tuesday Morning Snow Level
4000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
3500'
(Easterly Flow *)
Tuesday Night Snow Level
3000'
(Easterly Flow *)
Washington Pass Elevation
Monday Morning Freezing Level
10500'
(Easterly Flow *)
Monday Afternoon Freezing Level
10000'
(Easterly Flow *)
Monday Night Snow Level
5000'
(Easterly Flow *)
Tuesday Morning Snow Level
4000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
3500'
(Easterly Flow *)
Tuesday Night Snow Level
3000'
(Easterly Flow *)
Leavenworth Elevation
Monday Morning Freezing Level
'
(Easterly Flow *)
Monday Afternoon Freezing Level
'
(Easterly Flow *)
Monday Night Snow Level
'
(Easterly Flow *)
Tuesday Morning Snow Level
'
(Easterly Flow *)
Tuesday Afternoon Snow Level
'
(Easterly Flow *)
Tuesday Night Snow Level
'
(Easterly Flow *)
Stevens Pass Elevation
Monday Morning Freezing Level
'
(Easterly Flow *)
Monday Afternoon Freezing Level
'
(Easterly Flow *)
Monday Night Snow Level
'
(Easterly Flow *)
Tuesday Morning Snow Level
'
(Easterly Flow *)
Tuesday Afternoon Snow Level
'
(Easterly Flow *)
Tuesday Night Snow Level
'
(Easterly Flow *)
Snoqualmie Pass Elevation
Monday Morning Freezing Level
10500'
(Easterly Flow *)
Monday Afternoon Freezing Level
10000'
(Easterly Flow *)
Monday Night Snow Level
5500'
(Easterly Flow *)
Tuesday Morning Snow Level
4000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
3500'
(Easterly Flow *)
Tuesday Night Snow Level
3000'
(Easterly Flow *)
Mt. Rainier & Crystal Elevation
Monday Morning Freezing Level
'
(Easterly Flow *)
Monday Afternoon Freezing Level
'
(Easterly Flow *)
Monday Night Snow Level
'
(Easterly Flow *)
Tuesday Morning Snow Level
'
(Easterly Flow *)
Tuesday Afternoon Snow Level
'
(Easterly Flow *)
Tuesday Night Snow Level
'
(Easterly Flow *)
Mt. Hood Elevation
Monday Morning Freezing Level
10000'
(Easterly Flow *)
Monday Afternoon Freezing Level
9500'
(Easterly Flow *)
Monday Night Snow Level
5500'
(Easterly Flow *)
Tuesday Morning Snow Level
4000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
4000'
(Easterly Flow *)
Tuesday Night Snow Level
6000'
(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 0.25 - 0.50 LT 0.25
Mt Baker Ski Area LT 0.25 0.50 - 0.75
Washington Pass LT 0.10 0.25 - 0.50
Stevens Pass LT 0.10 LT 0.25
Snoqualmie Pass LT 0.25 LT 0.25
Mission Ridge LT 0.10 LT 0.25
Crystal Mt LT 0.25 LT 0.25
Paradise LT 0.25 0 - 0.50
White Pass LT 0.10 LT 0.25
Mt Hood Meadows LT 0.25 LT 0.25
LT 0.25 LT 0.25

Free Winds at 5000' (mph)

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

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.

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

Previous forecast from Jan 13, 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.