Issued: 1:13 PM PDT Thursday, March 17, 2016
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 Thursday & Friday

PM Update: No changes

An upper level ridge will build offshore today delivering a dry and mostly sunny day. Freezing levels will be on the rise Thursday, but warming will be muted by cool easterly flow for the Cascades. Broad surface high pressure over British Columbia/Alberta will slide south and spread into eastern Washington later today and overnight increasing offshore flow. Ridgetop winds for the central and southern Cascades and Cascade Passes will be breezy out of the east through Friday morning.

High clouds will spread over the area Friday from the west and the slow warming trend should pick up steam as cool easterly flow weakens. A weak front will wash out over the Cascades Friday night potentially bringing some light and spotty precipitation. 

Weather Forecast

Olympics, Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
Thursday - Thursday Night

Mostly sunny during the day and mostly clear at night. Light to moderate easterly ridgetop and Pass winds developing Thursday afternoon and overnight. 

Friday

Mostly clear in the morning becoming mostly cloudy with increasing high clouds in the afternoon. Slow warming trend. 

East slopes of the Washington Cascades
Thursday - Thursday Night

Mostly sunny during the day and mostly clear at night. 

Friday

Mostly clear in the morning becoming mostly cloudy with increasing high clouds late in the afternoon. Slow warming trend. 

Mt. Hood Area
Thursday - Thursday Night

Mostly sunny during the day and mostly clear at night. Light to moderate easterly mid-mountain winds developing Thursday afternoon and continuing overnight. 

Friday

Mostly clear in the morning becoming mostly cloudy with increasing high clouds in the afternoon. Slow warming trend. 

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 * 6000' 5000' 4500' ' ' 4500' ' 6000'
Thursday Night - Friday Morning Freezing Level * 7000' 3000' 1500' ' ' 2500' ' 4000'
Hurricane Ridge Elevation
Thursday Afternoon Freezing Level
6000'
(Easterly Flow *)
Thursday Night - Friday Morning Freezing Level
7000'
(Easterly Flow *)
Friday Afternoon - Friday Night Snow Level
8000'
(Easterly Flow *)
Mt. Baker Elevation
Thursday Afternoon Freezing Level
5000'
(Easterly Flow *)
Thursday Night - Friday Morning Freezing Level
3000'
(Easterly Flow *)
Friday Afternoon - Friday Night Snow Level
6000'
(Easterly Flow *)
Washington Pass Elevation
Thursday Afternoon Freezing Level
4500'
(Easterly Flow *)
Thursday Night - Friday Morning Freezing Level
1500'
(Easterly Flow *)
Friday Afternoon - Friday Night Snow Level
5000'
(Easterly Flow *)
Leavenworth Elevation
Thursday Afternoon Freezing Level
'
(Easterly Flow *)
Thursday Night - Friday Morning Freezing Level
'
(Easterly Flow *)
Friday Afternoon - Friday Night Snow Level
'
(Easterly Flow *)
Stevens Pass Elevation
Thursday Afternoon Freezing Level
'
(Easterly Flow *)
Thursday Night - Friday Morning Freezing Level
'
(Easterly Flow *)
Friday Afternoon - Friday Night Snow Level
'
(Easterly Flow *)
Snoqualmie Pass Elevation
Thursday Afternoon Freezing Level
4500'
(Easterly Flow *)
Thursday Night - Friday Morning Freezing Level
2500'
(Easterly Flow *)
Friday Afternoon - Friday Night Snow Level
6000'
(Easterly Flow *)
Mt. Rainier & Crystal Elevation
Thursday Afternoon Freezing Level
'
(Easterly Flow *)
Thursday Night - Friday Morning Freezing Level
'
(Easterly Flow *)
Friday Afternoon - Friday Night Snow Level
'
(Easterly Flow *)
Mt. Hood Elevation
Thursday Afternoon Freezing Level
6000'
(Easterly Flow *)
Thursday Night - Friday Morning Freezing Level
4000'
(Easterly Flow *)
Friday Afternoon - Friday Night Snow Level
8000'
(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

Friday Friday
Hurricane Ridge LT 0.10 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 0.10 LT 0.10
Mission Ridge LT 0.10 LT 0.10
Crystal Mt LT 0.10 LT 0.10
Paradise LT 0.10 LT 0.10
White Pass LT 0.10 LT 0.10
Mt Hood Meadows LT 0.10 LT 0.10
LT 0.10 LT 0.10

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Thursday Afternoon ESE 5 - 15 E 10 - 20 E 10 - 20 --- - ESE 15 - 25
Thursday Night - Friday Morning ESE 10 - 20 E 5 - 15 ESE 15 - 25 --- - ESE 15 - 30
Hurricane Ridge Elevation
Thursday Afternoon ESE 5 - 15
Thursday Night - Friday Morning ESE 10 - 20
Friday Afternoon - Friday Night SE 5 - 15
Mt. Baker Elevation
Thursday Afternoon E 10 - 20
Thursday Night - Friday Morning E 5 - 15
Friday Afternoon - Friday Night E 0 - 10
Stevens and Snoqualmie Pass Elevation
Thursday Afternoon E 10 - 20
Thursday Night - Friday Morning ESE 15 - 25
Friday Afternoon - Friday Night ESE 10 - 20
Mt. Rainier Elevation
Thursday Afternoon --- -
Thursday Night - Friday Morning --- -
Friday Afternoon - Friday Night --- -
Mt. Hood Elevation
Thursday Afternoon ESE 15 - 25
Thursday Night - Friday Morning ESE 15 - 30
Friday Afternoon - Friday Night ESE 5 - 15
Hurricane Ridge Direction - Speed
Thursday Afternoon ESE 5 - 15
Thursday Night - Friday Morning ESE 10 - 20
Friday Afternoon - Friday Night SE 5 - 15
Mt. Baker Direction - Speed
Thursday Afternoon E 10 - 20
Thursday Night - Friday Morning E 5 - 15
Friday Afternoon - Friday Night E 0 - 10
Stevens and Snoqualmie Pass Direction - Speed
Thursday Afternoon E 10 - 20
Thursday Night - Friday Morning ESE 15 - 25
Friday Afternoon - Friday Night ESE 10 - 20
Mt. Rainier Direction - Speed
Thursday Afternoon --- -
Thursday Night - Friday Morning --- -
Friday Afternoon - Friday Night --- -
Mt. Hood Direction - Speed
Thursday Afternoon ESE 15 - 25
Thursday Night - Friday Morning ESE 15 - 30
Friday Afternoon - Friday Night ESE 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
Thursday Afternoon NNE 15 - 25 NNE 0 - 10 N 10 - 20 --- - N 5 - 15
Thursday Night - Friday Morning NE 5 - 15 NE 0 - 10 NE 0 - 10 --- - SW 0 - 10
Mt. Baker Direction - Speed
Thursday Afternoon NNE 15 - 25
Thursday Night - Friday Morning NE 5 - 15
Friday Afternoon - Friday Night SW 5 - 15
Washington Pass Direction - Speed
Thursday Afternoon NNE 0 - 10
Thursday Night - Friday Morning NE 0 - 10
Friday Afternoon - Friday Night SW 5 - 15
Stevens and Snoqualmie Pass Direction - Speed
Thursday Afternoon N 10 - 20
Thursday Night - Friday Morning NE 0 - 10
Friday Afternoon - Friday Night SW 10 - 20
Mt. Rainier Direction - Speed
Thursday Afternoon --- -
Thursday Night - Friday Morning --- -
Friday Afternoon - Friday Night --- -
Mt. Hood Direction - Speed
Thursday Afternoon N 5 - 15
Thursday Night - Friday Morning SW 0 - 10
Friday Afternoon - Friday Night SW 10 - 20

Extended Weather Synopsis for Friday night through Friday

On Saturday, the upper level ridge will try to rebuild over central Washington with SW flow aloft over the region. Freezing levels will continue their slow rise as warm air continues to move into the region. Most forecast models are dry Saturday, but again light and spotty precipitation will be possible in this pattern with a fair amount of cloud cover likely.

Forecast models continue to differ on the timing of the next Pacific frontal system. Look for generally increasing moisture and clouds Saturday night and Sunday, with cloud bases lowering even along the east slopes of the Cascades. An occluded front will pass through sometime Sunday afternoon or evening with light to moderate precipitation. Snow levels will start off mild initially on Sunday and slowly lower through Monday as colder air moves in aloft. The parent upper level low offshore will migrate closer to the PNW on Monday, keeping showers and deep moisture directed into the region. The air mass should be unstable with generally weak S-SW flow aloft. 

Extended Weather

Olympics, Washington Cascades and Mt. Hood Area
Saturday

Partly to mostly cloudy Olympics, west slopes of the Cascades and Mt. Hood.  Partly to mostly sunny east slopes. Warming trend Saturday. 

Saturday Night - Sunday Morning

Mostly cloudy with increasing and lowering cloud bases with a chance of light rain or snow. 

Sunday Afternoon - Sunday Night

Light rain or snow developing and becoming light to moderate Sunday night. Cooling trend late Sunday night. 

Monday

Cloudy with light to occasionally moderate rain and snow showers. Cooler. 

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Saturday Snow Level 5500' - 6500' 6000' - 7000' 7000' - 8000'
Saturday Night - Sunday Snow Level 5000' - 6000' 5000' - 6000' 5500' - 6500'
Mt. Baker Elevation
Saturday Snow Level
5500' - 6500'
Saturday Night - Sunday Snow Level
5000' - 6000'
Sunday Night - Monday Snow Level
4000' - 5000'
Snoqualmie Pass Elevation
Saturday Snow Level
6000' - 7000'
Saturday Night - Sunday Snow Level
5000' - 6000'
Sunday Night - Monday Snow Level
4000' - 5000'
Mt. Hood Elevation
Saturday Snow Level
7000' - 8000'
Saturday Night - Sunday Snow Level
5500' - 6500'
Sunday Night - Monday Snow Level
4000' - 5000'

* 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 Mar 17, 2016

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