Issued: 1:34 PM PDT Thursday, April 19, 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 Thursday & Thursday

A tongue of high pressure is building from over the near shore waters on Thursday, ushered in between the departure of closed low now moving across the southwestern US and a trough over the north-central Pacific. The high pressure is bringing clear skies, light winds and far milder, spring-like conditions. Fair weather cumulus clouds will bring partly to mostly cloudy skies to the mountains, but the atmosphere is generally quite stable.

On Thursday night, the eastward movement of the central Pacific trough will push the high pressure tongue over the Pacific Northwest. Mostly clear skies will allow temperatures to cool overnight on Thursday, but freezing levels will remain elevated.

On Friday, the high pressure will continue to amplify as it moves to the east of our forecast area, while the offshore trough will bring increasing clouds and increasing SW flow aloft, late in the day. Friday will feature warm temperatures that will cool as light winds increase from the W or SW in the afternoon.

On Friday night, the trough will stretch from Alaska to the Northwest tip of Washington State. An associated N-S oriented cold-front will cross the Pacific Northwest shortly after midnight, bringing moderate to occasionally strong crest-level W-SW winds and light to moderate rain and snow becoming showery toward morning. Precipitation will be slightly heavier in the north than the south.

 

 

Weather Forecast

Olympics
Thursday Mostly sunny with some fair weather cumulus clouds.
Thursday Night Mostly clear with some high clouds.
Friday Increasing clouds with a chance of light rain or snow late in the day. Mild temperatures.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Thursday Partly cloudy this afternoon with fair weather cumulus clouds over the topography. Warm.
Thursday Night Mostly clear with increasing high clouds.
Friday Increasing clouds during the day. Warm.
East Slopes of the Washington Cascades
Thursday Partly cloudy this afternoon with fair weather cumulus clouds over the topography. Warm.
Thursday Night Mostly clear with increasing high clouds.
Friday Increasing clouds during the day. Warm.
Mt. Hood
Thursday Partly cloudy this afternoon with fair weather cumulus clouds over the topography. Warm.
Thursday Night Mostly clear with increasing high clouds.
Friday Increasing clouds during the day. Warm.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Thursday Afternoon Freezing Level 6500' 6000' 7000' ' ' 7000' ' 7500'
Thursday Night Freezing Level 6000' 5000' 5500' ' ' 6000' ' 7500'
Friday Morning Freezing Level 5500' 5500' 6000' ' ' 7000' ' 7500'
Friday Afternoon Freezing Level 5000' 6000' 7000' ' ' 7000' ' 8500'
Hurricane Ridge Elevation
Thursday Afternoon Freezing Level
6500'
Thursday Night Freezing Level
6000'
Friday Morning Freezing Level
5500'
Friday Afternoon Freezing Level
5000'
Friday Night Snow Level
3000'
Mt. Baker Elevation
Thursday Afternoon Freezing Level
6000'
Thursday Night Freezing Level
5000'
Friday Morning Freezing Level
5500'
Friday Afternoon Freezing Level
6000'
Friday Night Snow Level
3000'
Washington Pass Elevation
Thursday Afternoon Freezing Level
7000'
Thursday Night Freezing Level
5500'
Friday Morning Freezing Level
6000'
Friday Afternoon Freezing Level
7000'
Friday Night Snow Level
3500'
Leavenworth Elevation
Thursday Afternoon Freezing Level
'
Thursday Night Freezing Level
'
Friday Morning Freezing Level
'
Friday Afternoon Freezing Level
'
Friday Night Snow Level
'
Stevens Pass Elevation
Thursday Afternoon Freezing Level
'
Thursday Night Freezing Level
'
Friday Morning Freezing Level
'
Friday Afternoon Freezing Level
'
Friday Night Snow Level
'
Snoqualmie Pass Elevation
Thursday Afternoon Freezing Level
7000'
Thursday Night Freezing Level
6000'
Friday Morning Freezing Level
7000'
Friday Afternoon Freezing Level
7000'
Friday Night Snow Level
3500'
Mt. Rainier & Crystal Elevation
Thursday Afternoon Freezing Level
'
Thursday Night Freezing Level
'
Friday Morning Freezing Level
'
Friday Afternoon Freezing Level
'
Friday Night Snow Level
'
Mt. Hood Elevation
Thursday Afternoon Freezing Level
7500'
Thursday Night Freezing Level
7500'
Friday Morning Freezing Level
7500'
Friday Afternoon Freezing Level
8500'
Friday Night Snow Level
4000'

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

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Thursday Afternoon W 5 - 15 W 5 - 15 W 5 - 15 --- - W 5 - 15
Thursday Night SW 10 - 20 WSW 5 - 15 W 5 - 15 --- - W 5 - 15
Friday Morning SW 15 - 25 SSW 10 - 20 W 5 - 15 --- - W 5 - 15
Friday Afternoon SW 20 - 30 SSW 15 - 25 W 10 - 20 --- - W 10 - 20
Hurricane Ridge Elevation
Thursday Afternoon W 5 - 15
Thursday Night SW 10 - 20
Friday Morning SW 15 - 25
Friday Afternoon SW 20 - 30
Friday Night SW 25 - 35
Mt. Baker Elevation
Thursday Afternoon W 5 - 15
Thursday Night WSW 5 - 15
Friday Morning SSW 10 - 20
Friday Afternoon SSW 15 - 25
Friday Night SW 25 - 35
Stevens and Snoqualmie Pass Elevation
Thursday Afternoon W 5 - 15
Thursday Night W 5 - 15
Friday Morning W 5 - 15
Friday Afternoon W 10 - 20
Friday Night WSW 25 - 35
Mt. Rainier Elevation
Thursday Afternoon --- -
Thursday Night --- -
Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Mt. Hood Elevation
Thursday Afternoon W 5 - 15
Thursday Night W 5 - 15
Friday Morning W 5 - 15
Friday Afternoon W 10 - 20
Friday Night W 30 - 40
Hurricane Ridge Direction - Speed
Thursday Afternoon W 5 - 15
Thursday Night SW 10 - 20
Friday Morning SW 15 - 25
Friday Afternoon SW 20 - 30
Friday Night SW 25 - 35
Mt. Baker Direction - Speed
Thursday Afternoon W 5 - 15
Thursday Night WSW 5 - 15
Friday Morning SSW 10 - 20
Friday Afternoon SSW 15 - 25
Friday Night SW 25 - 35
Stevens and Snoqualmie Pass Direction - Speed
Thursday Afternoon W 5 - 15
Thursday Night W 5 - 15
Friday Morning W 5 - 15
Friday Afternoon W 10 - 20
Friday Night WSW 25 - 35
Mt. Rainier Direction - Speed
Thursday Afternoon --- -
Thursday Night --- -
Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Mt. Hood Direction - Speed
Thursday Afternoon W 5 - 15
Thursday Night W 5 - 15
Friday Morning W 5 - 15
Friday Afternoon W 10 - 20
Friday Night W 30 - 40

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
Thursday Afternoon W 10 - 20 WSW 10 - 20 SW 10 - 20 --- - VAR 0 - 10
Thursday Night W 15 - 25 W 10 - 20 W 10 - 20 --- - W 10 - 20
Friday Morning WSW 15 - 25 WSW 10 - 20 WSW 10 - 20 --- - W 15 - 25
Friday Afternoon SW 20 - 30 SW 15 - 25 SW 15 - 25 --- - SW 15 - 25
Mt. Baker Direction - Speed
Thursday Afternoon W 10 - 20
Thursday Night W 15 - 25
Friday Morning WSW 15 - 25
Friday Afternoon SW 20 - 30
Friday Night SW 45 - 65
Washington Pass Direction - Speed
Thursday Afternoon WSW 10 - 20
Thursday Night W 10 - 20
Friday Morning WSW 10 - 20
Friday Afternoon SW 15 - 25
Friday Night WSW 35 - 50
Stevens and Snoqualmie Pass Direction - Speed
Thursday Afternoon SW 10 - 20
Thursday Night W 10 - 20
Friday Morning WSW 10 - 20
Friday Afternoon SW 15 - 25
Friday Night SW 40 - 60
Mt. Rainier Direction - Speed
Thursday Afternoon --- -
Thursday Night --- -
Friday Morning --- -
Friday Afternoon --- -
Friday Night --- -
Mt. Hood Direction - Speed
Thursday Afternoon VAR 0 - 10
Thursday Night W 10 - 20
Friday Morning W 15 - 25
Friday Afternoon SW 15 - 25
Friday Night SW 40 - 60

Extended Weather Synopsis for Thursday night through Thursday

On Saturday, trough over Washington state will shift east of the forecast area as the associated frontal system exits the region with light rain and snow showers rapidly decreasing during the morning hours leaving isolated shower activity in the central and north Cascades. Skies will clear east of the Cascade crest during the day. 

Saturday night through Monday will feature mostly clear skies, generally light winds, and warming with stronger warming as the high pressure builds more strongly Sunday night into Monday as freezing levels rise to well above crest level by Monday.

Extended Weather

Olympics, Washington Cascades and Mt. Hood Area
Saturday Decreasing light showers, mainly near and west of the Cascade crest and heaviest in convergence likely developing between Stevens to Snoqualmie Pass. Showers ending by afternoon in the southern part and lingering slightly in the central and north. Clearing skies overnight. Sunday Mostly sunny on Sunday. Mostly clear on Sunday night. Warming. Monday Mostly sunny and quite warm.

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Saturday Snow Level 2500' - 3500' 3000' - 4000' 3000' - 4000'
Saturday Night Freezing Level 3000' - 4000' 3000' - 4000' 4500' - 5500'
Sunday Freezing Level 4000' - 6000' 4500' - 6500' 5000' - 7000'
Sunday Night Snow Level 5000' - 6000' 5500' - 6500' 7000' - 8000'
Mt. Baker Elevation
Saturday Snow Level
2500' - 3500'
Saturday Night Freezing Level
3000' - 4000'
Sunday Freezing Level
4000' - 6000'
Sunday Night Snow Level
5000' - 6000'
Monday Snow Level
6500' - 8500'
Snoqualmie Pass Elevation
Saturday Snow Level
3000' - 4000'
Saturday Night Freezing Level
3000' - 4000'
Sunday Freezing Level
4500' - 6500'
Sunday Night Snow Level
5500' - 6500'
Monday Snow Level
7000' - 9000'
Mt. Hood Elevation
Saturday Snow Level
3000' - 4000'
Saturday Night Freezing Level
4500' - 5500'
Sunday Freezing Level
5000' - 7000'
Sunday Night Snow Level
7000' - 8000'
Monday Snow Level
9000' - 11000'

* 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 Apr 14, 2018

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