Issued: 2:17 PM PDT Tuesday, March 18, 2014
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 Tuesday & Friday

A Pacific frontal system aimed at the central British Columbia coast today should bring mostly cloudy skies and periods of very light rain and snow to the north Cascades and Olympics with decreasing cloud cover further south over the southern Washington Cascades and Mt. Hood area.  After a cool start Tuesday morning, temperatures have warmed up to near or above freezing at many mountain stations.   

Snow levels should plateau overnight and through Wednesday morning as the frontal band slowly sags south toward the US border.  The front is forecast to cross the Cascades in the early afternoon Wednesday, bringing a rapid increase in precipitation intensity and winds during the day and a sharp cooling trend by later in the afternoon.  Post frontal showers in cool northwesterly flow should bring light moderate snow showers to the west slopes.  Mesoscale forecast models indicate one or more convergence zones in the central Cascades near Stevens and Snoqualmie Passes that could locally produce higher snowfall totals through early Thursday morning.

Sadly, the newest forecast guidance from this morning shows less water (and snowfall) during and behind the front through Thursday morning.  The Day 2 QPF forecast has been adjusted down to reflect this trend. 

Weather Forecast

Olympics and North Cascades
Tuesday

Mostly cloudy with periods of very light rain and snow.  Gradual warming. 

Tuesday Night

Light rain and snow developing after midnight. 

Wednesday Morning

Light to moderate rain and snow.  

Wednesday Afternoon - Wednesday Evening

Moderate rain and snow becoming light to moderate showers in the afternoon with a sharp cooling trend.  Becoming windy. 

Central and South Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
Tuesday

Partly sunny south Cascades and partly to mostly cloudy central Cascades.  Gradual warming. 

Tuesday Night

Becoming mostly cloudy. Light rain and snow developing late Tuesday night. 

Wednesday Morning

Light to moderate rain and snow spreading south during the morning, clouds lowering.  

Wednesday Afternoon - Wednesday Evening

Moderate rain and snow becoming light to moderate showers in the afternoon with a sharp cooling trend.  Showers possibly heavy near a convergence zone.  Becoming windy. 

East slopes of the Washington Cascades
Tuesday

Partly sunny southeast Cascades and mostly cloudy northeast Cascades.  Gradual warming. 

Tuesday Night

Becoming mostly cloudy with light rain and snow developing late tonight northeast Cascades. 

Wednesday Morning

Light to occasionally moderate rain and snow near the crest spreading south.   

Wednesday Afternoon - Wednesday Evening

Light to moderate rain and snow becoming light showers in the afternoon with a sharp cooling trend.  Showers heaviest near the crest and a convergence zone.  Becoming windy. 

Mt. Hood Area
Tuesday

Partly sunny with some high clouds.  Gradual warming. 

Tuesday Night

Partly cloudy.

Wednesday Morning

Becoming mostly cloudy with light rain and snow possible late morning. 

Wednesday Afternoon - Wednesday Evening

Light to moderate rain and snow becoming light to moderate showers in the late afternoon.   Sharp cooling trend.  Becoming windy. 

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Tuesday Afternoon - Wednesday Mid-day Snow Level 4000' ' ' ' ' 3500' ' 4500'
Wednesday Afternoon Snow Level 2000' ' ' ' ' 2500' ' 3500'
Hurricane Ridge Elevation
Tuesday Afternoon - Wednesday Mid-day Snow Level
4000'
Wednesday Afternoon Snow Level
2000'
Wednesday Night Snow Level
1500'
Mt. Baker Elevation
Tuesday Afternoon - Wednesday Mid-day Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Washington Pass Elevation
Tuesday Afternoon - Wednesday Mid-day Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Leavenworth Elevation
Tuesday Afternoon - Wednesday Mid-day Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Stevens Pass Elevation
Tuesday Afternoon - Wednesday Mid-day Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Snoqualmie Pass Elevation
Tuesday Afternoon - Wednesday Mid-day Snow Level
3500'
Wednesday Afternoon Snow Level
2500'
Wednesday Night Snow Level
1000'
Mt. Rainier & Crystal Elevation
Tuesday Afternoon - Wednesday Mid-day Snow Level
'
Wednesday Afternoon Snow Level
'
Wednesday Night Snow Level
'
Mt. Hood Elevation
Tuesday Afternoon - Wednesday Mid-day Snow Level
4500'
Wednesday Afternoon Snow Level
3500'
Wednesday Night Snow Level
1500'

* 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 0.25 0.25 - 0.50
Mt Baker Ski Area LT 0.25 0.75 - 1.00
Washington Pass LT 0.10 0 - 0.50
Stevens Pass LT 0.10 0 - 1.00
Snoqualmie Pass LT 0.10 0.75 - 1.00
Mission Ridge LT 0.10 LT 0.25
Crystal Mt LT 0.10 0.25 - 0.50
Paradise LT 0.10 0.50 - 0.75
White Pass LT 0.10 0.25 - 0.50
Mt Hood Meadows LT 0.10 0 - 0.50
LT 0.10 0.50 - 0.75

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Tuesday Afternoon - Tuesday Night W 0 - 10 --- - W 0 - 10 --- - W 0 - 10
Wednesday Morning SW 15 - 25 --- - SW 15 - 25 --- - W 5 - 15
Wednesday Afternoon - Wednesday Evening NW 20 - 30 --- - WSW 25 - 35 --- - W 25 - 35
Hurricane Ridge Elevation
Tuesday Afternoon - Tuesday Night W 0 - 10
Wednesday Morning SW 15 - 25
Wednesday Afternoon - Wednesday Evening NW 20 - 30
Wednesday Night NW 15 - 25
Mt. Baker Elevation
Tuesday Afternoon - Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon - Wednesday Evening --- -
Wednesday Night --- -
Stevens and Snoqualmie Pass Elevation
Tuesday Afternoon - Tuesday Night W 0 - 10
Wednesday Morning SW 15 - 25
Wednesday Afternoon - Wednesday Evening WSW 25 - 35
Wednesday Night W 10 - 20
Mt. Rainier Elevation
Tuesday Afternoon - Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon - Wednesday Evening --- -
Wednesday Night --- -
Mt. Hood Elevation
Tuesday Afternoon - Tuesday Night W 0 - 10
Wednesday Morning W 5 - 15
Wednesday Afternoon - Wednesday Evening W 25 - 35
Wednesday Night WNW 10 - 20
Hurricane Ridge Direction - Speed
Tuesday Afternoon - Tuesday Night W 0 - 10
Wednesday Morning SW 15 - 25
Wednesday Afternoon - Wednesday Evening NW 20 - 30
Wednesday Night NW 15 - 25
Mt. Baker Direction - Speed
Tuesday Afternoon - Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon - Wednesday Evening --- -
Wednesday Night --- -
Stevens and Snoqualmie Pass Direction - Speed
Tuesday Afternoon - Tuesday Night W 0 - 10
Wednesday Morning SW 15 - 25
Wednesday Afternoon - Wednesday Evening WSW 25 - 35
Wednesday Night W 10 - 20
Mt. Rainier Direction - Speed
Tuesday Afternoon - Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon - Wednesday Evening --- -
Wednesday Night --- -
Mt. Hood Direction - Speed
Tuesday Afternoon - Tuesday Night W 0 - 10
Wednesday Morning W 5 - 15
Wednesday Afternoon - Wednesday Evening W 25 - 35
Wednesday Night WNW 10 - 20

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
Tuesday Afternoon - Tuesday Night --- - --- - NW 10 - 20 --- - WNW 5 - 15
Wednesday Morning --- - --- - W 15 - 25 --- - W 10 - 20
Wednesday Afternoon - Wednesday Evening --- - --- - W 40 - 60 --- - W 45 - 55
Mt. Baker Direction - Speed
Tuesday Afternoon - Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon - Wednesday Evening --- -
Wednesday Night --- -
Washington Pass Direction - Speed
Tuesday Afternoon - Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon - Wednesday Evening --- -
Wednesday Night --- -
Stevens and Snoqualmie Pass Direction - Speed
Tuesday Afternoon - Tuesday Night NW 10 - 20
Wednesday Morning W 15 - 25
Wednesday Afternoon - Wednesday Evening W 40 - 60
Wednesday Night NW 35 - 45
Mt. Rainier Direction - Speed
Tuesday Afternoon - Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon - Wednesday Evening --- -
Wednesday Night --- -
Mt. Hood Direction - Speed
Tuesday Afternoon - Tuesday Night WNW 5 - 15
Wednesday Morning W 10 - 20
Wednesday Afternoon - Wednesday Evening W 45 - 55
Wednesday Night NW 35 - 50

Extended Weather Synopsis for Friday night through Friday

Cool northwest flow should continue on Thursday with light to moderate snow showers tapering off Thursday night.  An embedded upper level disturbance in the NW flow Thursday may temporarily enhance shower activity during the day, mainly for the west slopes.  An upper level ridge forecast of varying strengths, should build over the area Friday and Friday night.  Some forecast models have clouds and dribs and drabs of light rain and snow for the north Cascades and Olympics Friday sneaking under the weak ridge.  A weather system is forecast to push the ridge to the east on Friday night and come down from the northwest and over the are sometime on Saturday.  Snow levels should moderate gradually beginning Friday.  

Extended Weather

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

Light to moderate snow showers.  Cool.  

Thursday Night

Mostly cloudy with scattered light snow showers diminishing overnight. 

Friday - Friday Night

Partly cloudy and fair. 

Saturday

Light to moderate rain and snow developing Olympics and Cascades in the morning and spreading south during the day. 

East slopes of the Washington Cascades
Thursday

Mostly cloudy with light snow showers mainly near the crest.  Cool.  

Thursday Night

Partly cloudy with isolated light snow showers diminishing overnight. 

Friday - Friday Night

Partly cloudy and fair. 

Saturday

Light to moderate rain and snow developing in the morning and spreading south during the day. 

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Thursday - Thursday Night Snow Level ' - ' 1000' - 2000' 1500' - 3000'
Friday - Friday Night Freezing Level ' - ' 3500' - 4500' 4000' - 5000'
Mt. Baker Elevation
Thursday - Thursday Night Snow Level
' - '
Friday - Friday Night Freezing Level
' - '
Saturday Snow Level
' - '
Snoqualmie Pass Elevation
Thursday - Thursday Night Snow Level
1000' - 2000'
Friday - Friday Night Freezing Level
3500' - 4500'
Saturday Snow Level
2500' - 3500'
Mt. Hood Elevation
Thursday - Thursday Night Snow Level
1500' - 3000'
Friday - Friday Night Freezing Level
4000' - 5000'
Saturday 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 18, 2014

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