Issued: 7:19 AM PST Sunday, December 29, 2013
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 & Sunday

Light rain and snow at moderate snow levels should slip under the ever familiar upper level ridge that continues to persist offshore.  Light precipitation should be confined mainly from about Stevens Pass and north, while partly to mostly sunny conditions are seen elsewhere. 

High clouds should increase toward Monday morning as a weak frontal system around the central B.C coast sags south.  The front will briefly flatten the upper level ridge and spread some light precipitation mainly to the Olympics and north Cascades Monday afternoon and night.   Light rain and snow should reach the southern Washington Cascades by late Monday night. 

 

Weather Forecast

Olympics and Washington Cascades
Sunday

Mostly cloudy with periods of light rain and snow Olympics and north Cascades.  Partly cloudy central and southern Washington Cascades. 

Sunday Night - Monday Morning

Mostly cloudy north and partly cloudy central and south with increasing high clouds overnight. 

Monday Afternoon - Monday Evening

Light rain and snow developing Olympics and north Cascades Monday afternoon and spreading to central and south Cascades in the evening. 

Mt. Hood Area
Sunday

Partly to mostly sunny.  

Sunday Night - Monday Morning

Mostly clear, then becoming partly cloudy with high clouds increasing late tonight. 

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Sunday Morning Freezing Level 7000' ' ' ' ' 3500' ' 5000'
Sunday Afternoon - Sunday Evening Snow Level 5500' ' ' ' ' 5500' ' 8000'
Sunday Night - Monday Morning Snow Level 8500' ' ' ' ' 6500' ' 10000'
Monday Afternoon Snow Level 5000' ' ' ' ' 5500' ' 7000'
Hurricane Ridge Elevation
Sunday Morning Freezing Level
7000'
Sunday Afternoon - Sunday Evening Snow Level
5500'
Sunday Night - Monday Morning Snow Level
8500'
Monday Afternoon Snow Level
5000'
Monday Night Snow Level
5500'
Mt. Baker Elevation
Sunday Morning Freezing Level
'
Sunday Afternoon - Sunday Evening Snow Level
'
Sunday Night - Monday Morning Snow Level
'
Monday Afternoon Snow Level
'
Monday Night Snow Level
'
Washington Pass Elevation
Sunday Morning Freezing Level
'
Sunday Afternoon - Sunday Evening Snow Level
'
Sunday Night - Monday Morning Snow Level
'
Monday Afternoon Snow Level
'
Monday Night Snow Level
'
Leavenworth Elevation
Sunday Morning Freezing Level
'
Sunday Afternoon - Sunday Evening Snow Level
'
Sunday Night - Monday Morning Snow Level
'
Monday Afternoon Snow Level
'
Monday Night Snow Level
'
Stevens Pass Elevation
Sunday Morning Freezing Level
'
Sunday Afternoon - Sunday Evening Snow Level
'
Sunday Night - Monday Morning Snow Level
'
Monday Afternoon Snow Level
'
Monday Night Snow Level
'
Snoqualmie Pass Elevation
Sunday Morning Freezing Level
3500'
Sunday Afternoon - Sunday Evening Snow Level
5500'
Sunday Night - Monday Morning Snow Level
6500'
Monday Afternoon Snow Level
5500'
Monday Night Snow Level
4000'
Mt. Rainier & Crystal Elevation
Sunday Morning Freezing Level
'
Sunday Afternoon - Sunday Evening Snow Level
'
Sunday Night - Monday Morning Snow Level
'
Monday Afternoon Snow Level
'
Monday Night Snow Level
'
Mt. Hood Elevation
Sunday Morning Freezing Level
5000'
Sunday Afternoon - Sunday Evening Snow Level
8000'
Sunday Night - Monday Morning Snow Level
10000'
Monday Afternoon Snow Level
7000'
Monday Night Snow Level
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.

Precipitation Forecast

Sunday Sunday
Hurricane Ridge LT 0.10 LT 0.25
Mt Baker Ski Area LT 0.10 0.25 - 0.50
Washington Pass LT 0.10 LT 0.10
Stevens Pass LT 0.10 LT 0.25
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
Sunday - Morning NW 5 - 15 --- - NW 5 - 15 --- - NW 5 - 15
Sunday Afternoon NW 10 - 20 --- - NW 5 - 15 --- - NW 10 - 20
Sunday Night - Monday Morning WSW 5 - 15 --- - W 5 - 15 --- - W 5 - 15
Monday Afternoon - Monday Evening W 15 - 25 --- - WSW 10 - 20 --- - W 15 - 25
Hurricane Ridge Elevation
Sunday - Morning NW 5 - 15
Sunday Afternoon NW 10 - 20
Sunday Night - Monday Morning WSW 5 - 15
Monday Afternoon - Monday Evening W 15 - 25
Monday Night W 5 - 15
Mt. Baker Elevation
Sunday - Morning --- -
Sunday Afternoon --- -
Sunday Night - Monday Morning --- -
Monday Afternoon - Monday Evening --- -
Monday Night --- -
Stevens and Snoqualmie Pass Elevation
Sunday - Morning NW 5 - 15
Sunday Afternoon NW 5 - 15
Sunday Night - Monday Morning W 5 - 15
Monday Afternoon - Monday Evening WSW 10 - 20
Monday Night SW 5 - 15
Mt. Rainier Elevation
Sunday - Morning --- -
Sunday Afternoon --- -
Sunday Night - Monday Morning --- -
Monday Afternoon - Monday Evening --- -
Monday Night --- -
Mt. Hood Elevation
Sunday - Morning NW 5 - 15
Sunday Afternoon NW 10 - 20
Sunday Night - Monday Morning W 5 - 15
Monday Afternoon - Monday Evening W 15 - 25
Monday Night W 15 - 25
Hurricane Ridge Direction - Speed
Sunday - Morning NW 5 - 15
Sunday Afternoon NW 10 - 20
Sunday Night - Monday Morning WSW 5 - 15
Monday Afternoon - Monday Evening W 15 - 25
Monday Night W 5 - 15
Mt. Baker Direction - Speed
Sunday - Morning --- -
Sunday Afternoon --- -
Sunday Night - Monday Morning --- -
Monday Afternoon - Monday Evening --- -
Monday Night --- -
Stevens and Snoqualmie Pass Direction - Speed
Sunday - Morning NW 5 - 15
Sunday Afternoon NW 5 - 15
Sunday Night - Monday Morning W 5 - 15
Monday Afternoon - Monday Evening WSW 10 - 20
Monday Night SW 5 - 15
Mt. Rainier Direction - Speed
Sunday - Morning --- -
Sunday Afternoon --- -
Sunday Night - Monday Morning --- -
Monday Afternoon - Monday Evening --- -
Monday Night --- -
Mt. Hood Direction - Speed
Sunday - Morning NW 5 - 15
Sunday Afternoon NW 10 - 20
Sunday Night - Monday Morning W 5 - 15
Monday Afternoon - Monday Evening W 15 - 25
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.

Free Winds at 9000' (mph)

Mt. Baker Washington Pass Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Sunday Morning --- - --- - NW 40 - 50 --- - NW 25 - 40
Sunday Afternoon --- - --- - NW 35 - 45 --- - NW 25 - 35
Sunday Night - Monday Morning --- - --- - NW 20 - 30 --- - WNW 15 - 25
Mt. Baker Direction - Speed
Sunday Morning --- -
Sunday Afternoon --- -
Sunday Night - Monday Morning --- -
Monday Afternoon - Monday Night --- -
Washington Pass Direction - Speed
Sunday Morning --- -
Sunday Afternoon --- -
Sunday Night - Monday Morning --- -
Monday Afternoon - Monday Night --- -
Stevens and Snoqualmie Pass Direction - Speed
Sunday Morning NW 40 - 50
Sunday Afternoon NW 35 - 45
Sunday Night - Monday Morning NW 20 - 30
Monday Afternoon - Monday Night W 35 - 50
Mt. Rainier Direction - Speed
Sunday Morning --- -
Sunday Afternoon --- -
Sunday Night - Monday Morning --- -
Monday Afternoon - Monday Night --- -
Mt. Hood Direction - Speed
Sunday Morning NW 25 - 40
Sunday Afternoon NW 25 - 35
Sunday Night - Monday Morning WNW 15 - 25
Monday Afternoon - Monday Night W 30 - 45

Extended Weather Synopsis for Sunday night through Sunday

An upper level feature following on the heals of the weak frontal boundary may deliver a period of moderate to even heavy precipitation by mid-morning Tuesday for the central Cascades.  There is not much cooling with this system, and snow levels look to be rather moderate. A drying trend should ensue Tuesday afternoon and dry weather should last through Wednesday as the upper level ridge rebuilds offshore.

An open shortwave trough may approach the area on Wednesday night spreading light precipitation inland with light precipitation continuing on Thursday. 

Extended Weather

Olympics and Washington Cascades
Tuesday Morning

Light to moderate rain and snow, except occasionally heavy central Cascades Tuesday mid-morning. 

Tuesday Afternoon - Tuesday Night

Light rain and snow tapering off from north to south Tuesday afternoon and evening and becoming mostly cloudy. 

Wednesday

Partly to mostly cloudy. 

Wednesday Night - Thursday

Periods of light rain and snow. 

Mt. Hood Area
Tuesday Morning

Cloudy with very light rain and snow possible. 

Tuesday Afternoon - Tuesday Night

Mostly cloudy. 

Wednesday

Partly cloudy. 

Wednesday Night - Thursday

Periods of light rain and snow. 

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Tuesday - Tuesday Night Snow Level ' - ' 3500' - 4500' 4500' - 5500'
Wednesday Freezing Level ' - ' 5500' - 6500' 8500' - 9500'
Wednesday Night Snow Level ' - ' 4000' - 5000' 5000' - 6000'
Mt. Baker Elevation
Tuesday - Tuesday Night Snow Level
' - '
Wednesday Freezing Level
' - '
Wednesday Night Snow Level
' - '
Thursday Snow Level
' - '
Snoqualmie Pass Elevation
Tuesday - Tuesday Night Snow Level
3500' - 4500'
Wednesday Freezing Level
5500' - 6500'
Wednesday Night Snow Level
4000' - 5000'
Thursday Snow Level
5000' - 6000'
Mt. Hood Elevation
Tuesday - Tuesday Night Snow Level
4500' - 5500'
Wednesday Freezing Level
8500' - 9500'
Wednesday Night Snow Level
5000' - 6000'
Thursday Snow Level
6000' - 7000'

* 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 26, 2013

The NWAC program is administered by the USDA-Forest Service and operates from the National Weather Service Forecast Office in Seattle. NWAC services are made possible by important collaboration and support from a wide variety of federal, state and private cooperators.