Issued: 1:26 PM PST Sunday, January 4, 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 Sunday & Tuesday

Afternoon update:  Day 1 precipitation forecasts have been lowered at Crystal Mt, Mission Ridge and Hurricane due to strong shadowing today. Day 2 precipitation forecasts have been nudged lower almost everywhere with new model guidance.     

From prev discussion: A subtropical stream of moisture over the eastern Pacific will merge with an upper level low in the Gulf of Alaska today to drive copious amounts of moisture into the PNW over the next 48 hours. The upper level ridge offshore will flatten as this system develops... but the jet stream will stay well to our north allowing warm air to be pumped into the region. 

Snow levels will start low Sunday morning as warm frontal moisture spreads over the area during the day. Warm air will push inland during the daylight hours... but initial cool easterly flow should maintain only a gradual rise in snow levels for the Cascades. As the upper trough pushes through Sunday night... winds will become westerly in the passes and precipitation rates will increase. A sharp rise in snow levels should occur Sunday evening and continue overnight with snow generally changing to rain in the mountains. Precipitation will remain moderate to heavy along the west slopes of the Cascades and Olympics through Monday morning.  

Stormy conditions will begin to subside Monday afternoon as the upper level ridge rebuilds offshore and precipitation decreases from south to north during the day... and finally comes to an end Monday night.  

Weather Forecast

Olympics
Sunday Afternoon

Moderate rain and snow. Winds increasing. Strong warming trend.   
Sunday Night - Monday Morning

Stormy. Moderate to heavy rain and snow, heaviest west slopes of the Olympics. Mild. 
Monday Afternoon

Light to occasionally rain and snow. Mild. 
Monday Night

Periods of light rain and snow ending overnight. Mild. 
Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
Sunday Afternoon

Moderate rain and snow. Winds increasing. Gradual warming trend... except locally lower snow levels near the Cascade Passes. 
Sunday Night - Monday Morning

Stormy.  Heavy rain and snow with strong warming trend. 
Monday Afternoon

Light to moderate rain and snow. Mild. 
Monday Night

Periods of light rain and snow ending overnight. Mild. 
East slopes of the Washington Cascades
Sunday Afternoon

Light snow except moderate near the Cascade crest. Winds increasing.    
Sunday Night - Monday Morning

Stormy. Moderate rain and snow except heavy near the Cascade crest. Strong warming trend. 
Monday Afternoon

Light to occasionally moderate rain and snow. Mild. 
Monday Night

Periods of light rain and snow ending overnight. Mild. 
Mt. Hood Area
Sunday Afternoon

Moderate rain and snow. Winds increasing. Gradual warming trend.   
Sunday Night - Monday Morning

Stormy.  Heavy rain and snow with strong warming trend. 
Monday Mid-day - Monday Afternoon

Light to moderate rain and snow. Mild. 
Monday Night

Very light rain and snow ending overnight and becoming mostly cloudy. Mild. 

Issued: 1:26 PM PST Sunday, January 4, 2015

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Sunday Mid-day Snow Level * 5000' 2500' 1500' ' ' 2500' ' 4500'
Sunday Afternoon Snow Level * 8000' 3500' 2500' ' ' 4000' ' 5500'
Sunday Evening - Sunday Night Snow Level 10000' 6500' 5000' ' ' 7000' ' 8500'
Monday Morning Snow Level 9000' 5000' 5500' ' ' 7500' ' 8000'
Monday Afternoon - Monday Night Snow Level 7500' 7000' 6500' ' ' 7000' ' 8000'
Hurricane Ridge Elevation
Sunday Mid-day Snow Level
5000'
(Easterly Flow *)
Sunday Afternoon Snow Level
8000'
(Easterly Flow *)
Sunday Evening - Sunday Night Snow Level
10000'
Monday Morning Snow Level
9000'
Monday Afternoon - Monday Night Snow Level
7500'
Mt. Baker Elevation
Sunday Mid-day Snow Level
2500'
(Easterly Flow *)
Sunday Afternoon Snow Level
3500'
(Easterly Flow *)
Sunday Evening - Sunday Night Snow Level
6500'
Monday Morning Snow Level
5000'
Monday Afternoon - Monday Night Snow Level
7000'
Washington Pass Elevation
Sunday Mid-day Snow Level
1500'
(Easterly Flow *)
Sunday Afternoon Snow Level
2500'
(Easterly Flow *)
Sunday Evening - Sunday Night Snow Level
5000'
Monday Morning Snow Level
5500'
Monday Afternoon - Monday Night Snow Level
6500'
Leavenworth Elevation
Sunday Mid-day Snow Level
'
(Easterly Flow *)
Sunday Afternoon Snow Level
'
(Easterly Flow *)
Sunday Evening - Sunday Night Snow Level
'
Monday Morning Snow Level
'
Monday Afternoon - Monday Night Snow Level
'
Stevens Pass Elevation
Sunday Mid-day Snow Level
'
(Easterly Flow *)
Sunday Afternoon Snow Level
'
(Easterly Flow *)
Sunday Evening - Sunday Night Snow Level
'
Monday Morning Snow Level
'
Monday Afternoon - Monday Night Snow Level
'
Snoqualmie Pass Elevation
Sunday Mid-day Snow Level
2500'
(Easterly Flow *)
Sunday Afternoon Snow Level
4000'
(Easterly Flow *)
Sunday Evening - Sunday Night Snow Level
7000'
Monday Morning Snow Level
7500'
Monday Afternoon - Monday Night Snow Level
7000'
Mt. Rainier & Crystal Elevation
Sunday Mid-day Snow Level
'
(Easterly Flow *)
Sunday Afternoon Snow Level
'
(Easterly Flow *)
Sunday Evening - Sunday Night Snow Level
'
Monday Morning Snow Level
'
Monday Afternoon - Monday Night Snow Level
'
Mt. Hood Elevation
Sunday Mid-day Snow Level
4500'
(Easterly Flow *)
Sunday Afternoon Snow Level
5500'
(Easterly Flow *)
Sunday Evening - Sunday Night Snow Level
8500'
Monday Morning Snow Level
8000'
Monday Afternoon - Monday Night Snow Level
8000'

* 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

Tuesday Tuesday
Hurricane Ridge 1.00 - 1.50 0 - 0.50
Mt Baker Ski Area 0 - 3.00 1.00 - 1.50
Washington Pass 2.00 - 3.00 0.75 - 1.00
Stevens Pass 3.00 - 4.00 1.50 - 2.00
Snoqualmie Pass 0 - 4.00 2.00 - 2.50
Mission Ridge 0 - 1.00 LT 0.25
Crystal Mt 1.50 - 2.00 0.50 - 0.75
Paradise 4.00 - 5.00 0 - 1.50
White Pass 0 - 3.00 1.00 - 1.50
Mt Hood Meadows 0 - 3.00 0 - 0.50
Timberline 3.00 - 4.00 0 - 0.75

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: 1:26 PM PST Sunday, January 4, 2015

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Sunday Afternoon SW 30 - 40 SSW 15 - 25 SW 25 - 35 --- - SW 25 - 35
Sunday Night - Monday Morning WSW 30 - 40 SW 15 - 30 SW 40 - 55 --- - SW 45 - 55
Monday Afternoon W 25 - 35 SW 10 - 20 WSW 20 - 30 --- - SW 10 - 20
Monday Night SW 0 - 10 WSW 5 - 15 WSW 5 - 15 --- - WSW 5 - 15
Hurricane Ridge Elevation
Sunday Afternoon SW 30 - 40
Sunday Night - Monday Morning WSW 30 - 40
Monday Afternoon W 25 - 35
Monday Night SW 0 - 10
Mt. Baker Elevation
Sunday Afternoon SSW 15 - 25
Sunday Night - Monday Morning SW 15 - 30
Monday Afternoon SW 10 - 20
Monday Night WSW 5 - 15
Stevens and Snoqualmie Pass Elevation
Sunday Afternoon SW 25 - 35
Sunday Night - Monday Morning SW 40 - 55
Monday Afternoon WSW 20 - 30
Monday Night WSW 5 - 15
Mt. Rainier Elevation
Sunday Afternoon --- -
Sunday Night - Monday Morning --- -
Monday Afternoon --- -
Monday Night --- -
Mt. Hood Elevation
Sunday Afternoon SW 25 - 35
Sunday Night - Monday Morning SW 45 - 55
Monday Afternoon SW 10 - 20
Monday Night WSW 5 - 15
Hurricane Ridge Direction - Speed
Sunday Afternoon SW 30 - 40
Sunday Night - Monday Morning WSW 30 - 40
Monday Afternoon W 25 - 35
Monday Night SW 0 - 10
Mt. Baker Direction - Speed
Sunday Afternoon SSW 15 - 25
Sunday Night - Monday Morning SW 15 - 30
Monday Afternoon SW 10 - 20
Monday Night WSW 5 - 15
Stevens and Snoqualmie Pass Direction - Speed
Sunday Afternoon SW 25 - 35
Sunday Night - Monday Morning SW 40 - 55
Monday Afternoon WSW 20 - 30
Monday Night WSW 5 - 15
Mt. Rainier Direction - Speed
Sunday Afternoon --- -
Sunday Night - Monday Morning --- -
Monday Afternoon --- -
Monday Night --- -
Mt. Hood Direction - Speed
Sunday Afternoon SW 25 - 35
Sunday Night - Monday Morning SW 45 - 55
Monday Afternoon SW 10 - 20
Monday Night WSW 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
Sunday Afternoon SW 45 - 55 SW 50 - 60 WSW 45 - 55 --- - W 45 - 55
Sunday Night - Monday Morning WSW 45 - 60 W 45 - 60 W 50 - 70 --- - W 55 - 75
Monday Afternoon W 40 - 50 WNW 45 - 55 WNW 50 - 60 --- - NW 45 - 55
Monday Night W 30 - 40 WNW 35 - 45 W 30 - 40 --- - W 15 - 25
Mt. Baker Direction - Speed
Sunday Afternoon SW 45 - 55
Sunday Night - Monday Morning WSW 45 - 60
Monday Afternoon W 40 - 50
Monday Night W 30 - 40
Washington Pass Direction - Speed
Sunday Afternoon SW 50 - 60
Sunday Night - Monday Morning W 45 - 60
Monday Afternoon WNW 45 - 55
Monday Night WNW 35 - 45
Stevens and Snoqualmie Pass Direction - Speed
Sunday Afternoon WSW 45 - 55
Sunday Night - Monday Morning W 50 - 70
Monday Afternoon WNW 50 - 60
Monday Night W 30 - 40
Mt. Rainier Direction - Speed
Sunday Afternoon --- -
Sunday Night - Monday Morning --- -
Monday Afternoon --- -
Monday Night --- -
Mt. Hood Direction - Speed
Sunday Afternoon W 45 - 55
Sunday Night - Monday Morning W 55 - 75
Monday Afternoon NW 45 - 55
Monday Night W 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.

Issued: 1:26 PM PST Sunday, January 4, 2015

Extended Weather Synopsis for Tuesday night through Tuesday

A strong upper level ridge extending from the intermountain West through Washington state will keep dry weather and a mild air mass over the region through Thursday. Freezing levels will be high and skies mostly clear. Temperatures should be warmer in the alpine than in the valleys/passes during this period. A weak front may approach the coast on Thursday... spreading some high clouds over the Olympics later in the day. 

Extended Weather

Olympics, Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes and Mt. Hood Area
Tuesday

Becoming mostly clear from south to north on Tuesday. Mild.  

Wednesday - Thursday

Mostly clear. Mild.  Increasing clouds Thursday afternoon Olympics. 

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Tuesday - Wednesday Freezing Level 10000' - 11000' 10000' - 11000' 11000' - 12000'
Thursday Freezing Level 8000' - 9000' 8500' - 9500' 8500' - 9500' *
Mt. Baker Elevation
Tuesday - Wednesday Freezing Level
10000' - 11000'
Thursday Freezing Level
8000' - 9000'
(Easterly Flow *)
Snoqualmie Pass Elevation
Tuesday - Wednesday Freezing Level
10000' - 11000'
Thursday Freezing Level
8500' - 9500'
(Easterly Flow *)
Mt. Hood Elevation
Tuesday - Wednesday Freezing Level
11000' - 12000'
Thursday Freezing Level
8500' - 9500'
(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 4, 2015

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