Issued: 1:45 PM PST Thursday, December 31, 2015
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 & Saturday

2015 is going out on a quiet note weather-wise with high pressure firmly in control over the Pacific Northwest.  A rex block will form over the region...with upper level high pressure over British Columbia and an upper low retrograding over Califonia/Nevada through the short term. 

Warm air offshore will slowly work it's way inland over the next 2 days, mainly benefiting the Olympics and north Cacades. Moderate east winds will keep areas near the crest, the Passes and the east slopes cooler.  Mt. Hood will should stay under the cool easterly flow through the short term with stronger easterly winds.  

Weather Forecast

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

Mostly clear except for areas of low clouds and fog near the Cascade Passes. Moderate east-southeast winds increasing in the afternoon central and south Cascades and Cascade Passes. Warmer away from the Cascade crest including Olympics and Mt. Baker area. 
East slopes of the Washington Cascades
Thursday - Friday Night

Mostly clear except for areas of low clouds and fog lower slopes and valleys. Moderate east-southeast winds near the crest increasing Thursday afternoon. Slight warming trend Friday, especially northeast Cascades. 
Mt. Hood Area
Thursday - Friday Night

Mostly clear and cold. Moderate to strong east-southeast winds beginning early Thursday mid-day.  

Issued: 1:45 PM PST Thursday, December 31, 2015

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Thursday Morning Snow Level * 8000' 1000' 1000' ' ' 1000' ' 1000'
Thursday Afternoon - Thursday Night Snow Level * 8000' 6000' 1000' ' ' 1000' ' 1000'
Friday - Friday Night Snow Level * 8500' 8500' 5500' ' ' 6000' ' 2000'
Hurricane Ridge Elevation
Thursday Morning Snow Level
8000'
(Easterly Flow *)
Thursday Afternoon - Thursday Night Snow Level
8000'
(Easterly Flow *)
Friday - Friday Night Snow Level
8500'
(Easterly Flow *)
Mt. Baker Elevation
Thursday Morning Snow Level
1000'
(Easterly Flow *)
Thursday Afternoon - Thursday Night Snow Level
6000'
(Easterly Flow *)
Friday - Friday Night Snow Level
8500'
(Easterly Flow *)
Washington Pass Elevation
Thursday Morning Snow Level
1000'
(Easterly Flow *)
Thursday Afternoon - Thursday Night Snow Level
1000'
(Easterly Flow *)
Friday - Friday Night Snow Level
5500'
(Easterly Flow *)
Leavenworth Elevation
Thursday Morning Snow Level
'
(Easterly Flow *)
Thursday Afternoon - Thursday Night Snow Level
'
(Easterly Flow *)
Friday - Friday Night Snow Level
'
(Easterly Flow *)
Stevens Pass Elevation
Thursday Morning Snow Level
'
(Easterly Flow *)
Thursday Afternoon - Thursday Night Snow Level
'
(Easterly Flow *)
Friday - Friday Night Snow Level
'
(Easterly Flow *)
Snoqualmie Pass Elevation
Thursday Morning Snow Level
1000'
(Easterly Flow *)
Thursday Afternoon - Thursday Night Snow Level
1000'
(Easterly Flow *)
Friday - Friday Night Snow Level
6000'
(Easterly Flow *)
Mt. Rainier & Crystal Elevation
Thursday Morning Snow Level
'
(Easterly Flow *)
Thursday Afternoon - Thursday Night Snow Level
'
(Easterly Flow *)
Friday - Friday Night Snow Level
'
(Easterly Flow *)
Mt. Hood Elevation
Thursday Morning Snow Level
1000'
(Easterly Flow *)
Thursday Afternoon - Thursday Night Snow Level
1000'
(Easterly Flow *)
Friday - Friday Night Snow Level
2000'
(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 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
Timberline LT 0.10 LT 0.10

LT = less than; WE or Water equivalent is the liquid water equivalent of melted snow in hundredths of inches. As a rough approximation 1 inch of snow = about .10 inches WE, or 10 inches of snow = about 1 inch WE.

Issued: 1:45 PM PST Thursday, December 31, 2015

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Thursday Mid-day - Friday Afternoon SE 0 - 10 E 0 - 10 ESE 15 - 30 --- - ESE 20 - 30
Friday Night SE 0 - 10 E 0 - 10 SE 10 - 20 --- - SE 15 - 25
Hurricane Ridge Elevation
Thursday Mid-day - Friday Afternoon SE 0 - 10
Friday Night SE 0 - 10
Mt. Baker Elevation
Thursday Mid-day - Friday Afternoon E 0 - 10
Friday Night E 0 - 10
Stevens and Snoqualmie Pass Elevation
Thursday Mid-day - Friday Afternoon ESE 15 - 30
Friday Night SE 10 - 20
Mt. Rainier Elevation
Thursday Mid-day - Friday Afternoon --- -
Friday Night --- -
Mt. Hood Elevation
Thursday Mid-day - Friday Afternoon ESE 20 - 30
Friday Night SE 15 - 25
Hurricane Ridge Direction - Speed
Thursday Mid-day - Friday Afternoon SE 0 - 10
Friday Night SE 0 - 10
Mt. Baker Direction - Speed
Thursday Mid-day - Friday Afternoon E 0 - 10
Friday Night E 0 - 10
Stevens and Snoqualmie Pass Direction - Speed
Thursday Mid-day - Friday Afternoon ESE 15 - 30
Friday Night SE 10 - 20
Mt. Rainier Direction - Speed
Thursday Mid-day - Friday Afternoon --- -
Friday Night --- -
Mt. Hood Direction - Speed
Thursday Mid-day - Friday Afternoon ESE 20 - 30
Friday Night SE 15 - 25

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 Mid-day - Friday Morning SE 0 - 10 ESE 0 - 10 E 15 - 30 --- - E 40 - 50
Friday Afternoon - Friday Night SE 5 - 15 SE 5 - 15 SE 15 - 25 --- - SE 30 - 40
Mt. Baker Direction - Speed
Thursday Mid-day - Friday Morning SE 0 - 10
Friday Afternoon - Friday Night SE 5 - 15
Washington Pass Direction - Speed
Thursday Mid-day - Friday Morning ESE 0 - 10
Friday Afternoon - Friday Night SE 5 - 15
Stevens and Snoqualmie Pass Direction - Speed
Thursday Mid-day - Friday Morning E 15 - 30
Friday Afternoon - Friday Night SE 15 - 25
Mt. Rainier Direction - Speed
Thursday Mid-day - Friday Morning --- -
Friday Afternoon - Friday Night --- -
Mt. Hood Direction - Speed
Thursday Mid-day - Friday Morning E 40 - 50
Friday Afternoon - Friday Night SE 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.

Issued: 1:45 PM PST Thursday, December 31, 2015

Extended Weather Synopsis for Saturday night through Saturday

Saturday should be much of the same with freezing levels beginning to decrease as the upper low positioned south of the area migrates northward, and the easterly winds should decrease a notch as well.

A weak system should turn the upper flow southerly on Sunday... increasing the mid and high level cloud cover over the area.  Some light precipitation may glance the Olympic peninsula Sunday and Sunday night.  A weak shortwave may finally push some light rain and snow inland on Monday.  

Extended Weather

Olympics, Washington Cascades and Mt. Hood area
Saturday - Saturday Night

Mostly fair. 

Sunday - Sunday Night

Increasing clouds Sunday, becoming mostly cloudy. Light rain and snow possible Olympics Sunday and Sunday night. 

Monday

Mostly cloudy with periods of light rain and snow.  

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Saturday - Saturday Night Freezing Level 6000' - 7000' 4000' - 5000' 1000' - 2000' *
Sunday - Sunday Night Snow Level 1500' - 2500' 500' - 1500' 1000' - 2000' *
Monday Snow Level 3000' - 4000' 2500' - 3500' 3000' - 4000' *
Mt. Baker Elevation
Saturday - Saturday Night Freezing Level
6000' - 7000'
(Easterly Flow *)
Sunday - Sunday Night Snow Level
1500' - 2500'
(Easterly Flow *)
Monday Snow Level
3000' - 4000'
(Easterly Flow *)
Snoqualmie Pass Elevation
Saturday - Saturday Night Freezing Level
4000' - 5000'
(Easterly Flow *)
Sunday - Sunday Night Snow Level
500' - 1500'
(Easterly Flow *)
Monday Snow Level
2500' - 3500'
(Easterly Flow *)
Mt. Hood Elevation
Saturday - Saturday Night Freezing Level
1000' - 2000'
(Easterly Flow *)
Sunday - Sunday Night Snow Level
1000' - 2000'
(Easterly Flow *)
Monday Snow Level
3000' - 4000'
(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 Dec 31, 2015

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