Issued: 2:06 PM PST Tuesday, January 10, 2017
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 Tuesday & Thursday

A weak surface low traversed across southern Washington this morning producing a period of generally light snow for the south and central Washington Cascades with continuing moderate accumulations down at Mt. Hood. Light upslope snow showers with breezy NE winds should taper down along the north slopes of the Olympics tonight. The surface low is part of the E-W elongated trough stretched out over Washington state with the upper low centered offshore.  

A stronger low pressure system developing in the westerly jet aimed at northern California will approach the south Oregon coast this afternoon. Besides spreading renewed precipitation into the Mt. Hood region this afternoon, the pressure falls associated with this low pressure system will turn the winds E-NE throughout the Cascades and Olympics.

Forecast models indicate precipitation largely confined to the far south Washington Cascades and Mt. Hood tonight, but it's reasonable to assume their will be some light upslope snow showers along the east slopes from Mission Ridge and south overnight. The surface low will dissipate as it moves inland Wednesday morning but the weak upper level low circulation will remain parked off the WA/OR coast on Wednesday. Cold easterly flow should ease Wednesday afternoon but clouds should be more plentiful for both sides of the central and south Washington Cascades through mid-day Wednesday with mostly clear conditions expected close to the Canadian border through much of the short term period.  

Weather Forecast

Olympics
Tuesday - Tuesday Night

Partly to mostly cloudy with light snow showers north slopes of the Olympics. Light to moderate NE winds developing this afternoon through Tuesday night. Turning colder. 

Wednesday

Partly to mostly sunny. 

Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
Tuesday Night - Wednesday Morning

Cloudy with periods of light snow south Washington Cascades. Mostly cloudy with isolated snow showers central Cascades. Mostly clear north Cascades. Light to moderate E-NE winds developing this afternoon through Tuesday night. Turning colder. 

Wednesday Mid-day - Afternoon

Mostly sunny north Cascades. Mostly cloudy with isolated snow showers central and south Washington Cascades partially clearing in the afternoon. 

East slopes of the Washington Cascades
Tuesday - Wednesday Morning

Cloudy with periods of light snow mainly southeast Washington Cascades. Mostly clear northeast Cascades. Light to moderate E-NE winds developing this afternoon through Tuesday night. Turning colder. 

Wednesday Afternoon

Mostly sunny northeast Cascades. Partly cloudy with isolated snow showers central and southeast Washington Cascades. 

Mt. Hood Area
Tuesday - Wednesday Morning

Light to occasionally moderate snow. Moderate E winds developing this afternoon through Tuesday night. Turning colder. 

Wednesday Afternoon

Mostly cloudy with scattered 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 Mid-day Snow Level * 1000' 0' 0' ' ' 500' ' 2500'
Tuesday Afternoon Snow Level * 0' 0' 0' ' ' 0' ' 500'
Hurricane Ridge Elevation
Tuesday Mid-day Snow Level
1000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
0'
(Easterly Flow *)
Tuesday Night - Wednesday Night Snow Level
0'
(Easterly Flow *)
Mt. Baker Elevation
Tuesday Mid-day Snow Level
0'
(Easterly Flow *)
Tuesday Afternoon Snow Level
0'
(Easterly Flow *)
Tuesday Night - Wednesday Night Snow Level
0'
(Easterly Flow *)
Washington Pass Elevation
Tuesday Mid-day Snow Level
0'
(Easterly Flow *)
Tuesday Afternoon Snow Level
0'
(Easterly Flow *)
Tuesday Night - Wednesday Night Snow Level
0'
(Easterly Flow *)
Leavenworth Elevation
Tuesday Mid-day Snow Level
'
(Easterly Flow *)
Tuesday Afternoon Snow Level
'
(Easterly Flow *)
Tuesday Night - Wednesday Night Snow Level
'
(Easterly Flow *)
Stevens Pass Elevation
Tuesday Mid-day Snow Level
'
(Easterly Flow *)
Tuesday Afternoon Snow Level
'
(Easterly Flow *)
Tuesday Night - Wednesday Night Snow Level
'
(Easterly Flow *)
Snoqualmie Pass Elevation
Tuesday Mid-day Snow Level
500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
0'
(Easterly Flow *)
Tuesday Night - Wednesday Night Snow Level
0'
(Easterly Flow *)
Mt. Rainier & Crystal Elevation
Tuesday Mid-day Snow Level
'
(Easterly Flow *)
Tuesday Afternoon Snow Level
'
(Easterly Flow *)
Tuesday Night - Wednesday Night Snow Level
'
(Easterly Flow *)
Mt. Hood Elevation
Tuesday Mid-day Snow Level
2500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
500'
(Easterly Flow *)
Tuesday Night - Wednesday Night Snow Level
0'
(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

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

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Tuesday Afternoon NE 10 - 20 NE 15 - 25 ESE 10 - 20 --- - E 10 - 20
Tuesday Night NE 15 - 25 ENE 15 - 25 ESE 15 - 25 --- - E 15 - 30
Wednesday Morning NE 10 - 20 ENE 10 - 20 SE 10 - 20 --- - E 10 - 20
Hurricane Ridge Elevation
Tuesday Afternoon NE 10 - 20
Tuesday Night NE 15 - 25
Wednesday Morning NE 10 - 20
Wednesday Afternoon - Wednesday Night NE 0 - 10
Mt. Baker Elevation
Tuesday Afternoon NE 15 - 25
Tuesday Night ENE 15 - 25
Wednesday Morning ENE 10 - 20
Wednesday Afternoon - Wednesday Night NE 0 - 10
Stevens and Snoqualmie Pass Elevation
Tuesday Afternoon ESE 10 - 20
Tuesday Night ESE 15 - 25
Wednesday Morning SE 10 - 20
Wednesday Afternoon - Wednesday Night NE 0 - 10
Mt. Rainier Elevation
Tuesday Afternoon --- -
Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon - Wednesday Night --- -
Mt. Hood Elevation
Tuesday Afternoon E 10 - 20
Tuesday Night E 15 - 30
Wednesday Morning E 10 - 20
Wednesday Afternoon - Wednesday Night SE 0 - 10
Hurricane Ridge Direction - Speed
Tuesday Afternoon NE 10 - 20
Tuesday Night NE 15 - 25
Wednesday Morning NE 10 - 20
Wednesday Afternoon - Wednesday Night NE 0 - 10
Mt. Baker Direction - Speed
Tuesday Afternoon NE 15 - 25
Tuesday Night ENE 15 - 25
Wednesday Morning ENE 10 - 20
Wednesday Afternoon - Wednesday Night NE 0 - 10
Stevens and Snoqualmie Pass Direction - Speed
Tuesday Afternoon ESE 10 - 20
Tuesday Night ESE 15 - 25
Wednesday Morning SE 10 - 20
Wednesday Afternoon - Wednesday Night NE 0 - 10
Mt. Rainier Direction - Speed
Tuesday Afternoon --- -
Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon - Wednesday Night --- -
Mt. Hood Direction - Speed
Tuesday Afternoon E 10 - 20
Tuesday Night E 15 - 30
Wednesday Morning E 10 - 20
Wednesday Afternoon - Wednesday Night SE 0 - 10

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 NE 15 - 25 N 10 - 20 E 10 - 20 --- - S 20 - 30
Tuesday Night ENE 10 - 20 NE 10 - 20 ESE 15 - 25 --- - SW 25 - 35
Wednesday Morning ENE 5 - 15 NE 5 - 15 SE 15 - 25 --- - SW 15 - 25
Mt. Baker Direction - Speed
Tuesday Afternoon NE 15 - 25
Tuesday Night ENE 10 - 20
Wednesday Morning ENE 5 - 15
Wednesday Afternoon - Wednesday Night NE 5 - 15
Washington Pass Direction - Speed
Tuesday Afternoon N 10 - 20
Tuesday Night NE 10 - 20
Wednesday Morning NE 5 - 15
Wednesday Afternoon - Wednesday Night N 0 - 10
Stevens and Snoqualmie Pass Direction - Speed
Tuesday Afternoon E 10 - 20
Tuesday Night ESE 15 - 25
Wednesday Morning SE 15 - 25
Wednesday Afternoon - Wednesday Night VAR 0 - 10
Mt. Rainier Direction - Speed
Tuesday Afternoon --- -
Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon - Wednesday Night --- -
Mt. Hood Direction - Speed
Tuesday Afternoon S 20 - 30
Tuesday Night SW 25 - 35
Wednesday Morning SW 15 - 25
Wednesday Afternoon - Wednesday Night WSW 20 - 30

Extended Weather Synopsis for Thursday night through Thursday

A rather benign period of weather is expected as an upper level ridge of high pressure builds into British Columbia Thursday and slowly shifts over to the PNW by Saturday. Mainly clear and fair weather is expected Thursday through Saturday.  A weak warm front may brush the area Friday night mostly causing an increase in clouds. Offshore flow will continue through the extended but especially for areas west of the crest, temperatures should moderate Friday and continue on Saturday. 

Extended Weather

Olympics, Washington Cascades and Mt. Hood
Thursday - Friday

Mostly clear. Areas of low clouds along the east slopes and near the Cascade Passes. Slight warming trend Friday. 

Friday Night - Saturday

Partly north Cascades and Olympics with very light rain or snow possible. Mostly clear south Washington Cascades and Mt. Hood. Continued warming trend Saturday.  

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Thursday - Thursday Night Freezing Level 0' - 1000' 0' - 1000' 500' - 1500' *
Friday - Friday Night Freezing Level 2000' - 3000' 1500' - 2500' 3000' - 4000' *
Mt. Baker Elevation
Thursday - Thursday Night Freezing Level
0' - 1000'
(Easterly Flow *)
Friday - Friday Night Freezing Level
2000' - 3000'
(Easterly Flow *)
Saturday Freezing Level
3000' - 4000'
(Easterly Flow *)
Snoqualmie Pass Elevation
Thursday - Thursday Night Freezing Level
0' - 1000'
(Easterly Flow *)
Friday - Friday Night Freezing Level
1500' - 2500'
(Easterly Flow *)
Saturday Freezing Level
2000' - 4000'
(Easterly Flow *)
Mt. Hood Elevation
Thursday - Thursday Night Freezing Level
500' - 1500'
(Easterly Flow *)
Friday - Friday Night Freezing Level
3000' - 4000'
(Easterly Flow *)
Saturday Freezing Level
3000' - 5000'
(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 Jan 10, 2017

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