Issued: 2:32 PM PST Tuesday, February 27, 2018
by Robert Hahn

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 & Saturday

A cool weather pattern continues with a weak disturbance following a similar track to recent storms, arriving in W-NW flow aloft Tuesday with generally W flow at lower levels. The system is bringing periods of light snow on Tuesday and post-frontal snow showers will continue through the afternoon with enhanced snowfall rates in convergence zone likely to form early this evening somewhere between Stevens and Snoqualmie passes. Moderate crest-level westerly winds will peak during the afternoon hours.

Tonight, upper level flow will become westerly as a significant trough digs into the near coastal waters and an associated surface low drops south from Alaska. 

On Wednesday, the digging trough offshore will produce W-SW flow aloft and an offshore gradient will develop at lower levels, producing light to moderate easterly flow across the Cascades. A stronger cold front will approach and bring increasing light snow and increasing moderate crest-level winds, particularly during the afternoon hours.

On Wednesday evening, the surface front will cross the forecast zones bringing moderate to strong winds and moderate snow with a slight rise in snow level. Precipitation will become showery after the frontal passage and should become light to moderate after midnight with decreasing winds and a cooling trend.

Weather Forecast

Olympics
Tuesday Mostly cloudy.
Tuesday Night Partly to mostly cloudy.
Wednesday Partly cloudy with light snow developing in the afternoon.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Tuesday Cloudy with snow showers, heaviest in convergence late in the day in the central Cascades.
Tuesday Night Decreasing light snow showers, heaviest in convergence possible between Stevens and Snoqualmie during the early evening hours.
Wednesday Light snow developing in the morning, becoming moderate in the afternoon. Increasing southerly crest-level winds becoming moderate to occasionally strong.
East Slopes of the Washington Cascades
Tuesday Snow showers near the crest with decreasing clouds to the east.
Tuesday Night Decreasing light snow showers at high elevations.
Wednesday Light snow developing from south to north during the day and increasing southerly winds becoming moderate to occasionally strong.
Mt. Hood
Tuesday Cloudy with a mix of freezing drizzle and light snow showers.
Tuesday Night Cloudy with a chance of light snow.
Wednesday Light snow developing early and becoming moderate by afternoon. Light to moderate winds becoming moderate by afternoon.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Tuesday Morning Snow Level 2000' 1500' 1000' ' ' 1500' ' 1000'
Tuesday Afternoon Snow Level 2000' 2000' 2000' ' ' 2000' ' 2000'
Tuesday Night Snow Level 1500' 1500' 1000' ' ' 1000' ' 2000'
Wednesday Morning Snow Level * 2000' 2000' 1000' ' ' 2000' ' 2500'
Wednesday Afternoon Snow Level * 2500' 2000' 2000' ' ' 2000' ' 3000'
Hurricane Ridge Elevation
Tuesday Morning Snow Level
2000'
Tuesday Afternoon Snow Level
2000'
Tuesday Night Snow Level
1500'
Wednesday Morning Snow Level
2000'
(Easterly Flow *)
Wednesday Afternoon Snow Level
2500'
(Easterly Flow *)
Wednesday Night Snow Level
1500'
(Easterly Flow *)
Mt. Baker Elevation
Tuesday Morning Snow Level
1500'
Tuesday Afternoon Snow Level
2000'
Tuesday Night Snow Level
1500'
Wednesday Morning Snow Level
2000'
(Easterly Flow *)
Wednesday Afternoon Snow Level
2000'
(Easterly Flow *)
Wednesday Night Snow Level
2500'
(Easterly Flow *)
Washington Pass Elevation
Tuesday Morning Snow Level
1000'
Tuesday Afternoon Snow Level
2000'
Tuesday Night Snow Level
1000'
Wednesday Morning Snow Level
1000'
(Easterly Flow *)
Wednesday Afternoon Snow Level
2000'
(Easterly Flow *)
Wednesday Night Snow Level
1500'
(Easterly Flow *)
Leavenworth Elevation
Tuesday Morning Snow Level
'
Tuesday Afternoon Snow Level
'
Tuesday Night Snow Level
'
Wednesday Morning Snow Level
'
(Easterly Flow *)
Wednesday Afternoon Snow Level
'
(Easterly Flow *)
Wednesday Night Snow Level
'
(Easterly Flow *)
Stevens Pass Elevation
Tuesday Morning Snow Level
'
Tuesday Afternoon Snow Level
'
Tuesday Night Snow Level
'
Wednesday Morning Snow Level
'
(Easterly Flow *)
Wednesday Afternoon Snow Level
'
(Easterly Flow *)
Wednesday Night Snow Level
'
(Easterly Flow *)
Snoqualmie Pass Elevation
Tuesday Morning Snow Level
1500'
Tuesday Afternoon Snow Level
2000'
Tuesday Night Snow Level
1000'
Wednesday Morning Snow Level
2000'
(Easterly Flow *)
Wednesday Afternoon Snow Level
2000'
(Easterly Flow *)
Wednesday Night Snow Level
2000'
(Easterly Flow *)
Mt. Rainier & Crystal Elevation
Tuesday Morning Snow Level
'
Tuesday Afternoon Snow Level
'
Tuesday Night Snow Level
'
Wednesday Morning Snow Level
'
(Easterly Flow *)
Wednesday Afternoon Snow Level
'
(Easterly Flow *)
Wednesday Night Snow Level
'
(Easterly Flow *)
Mt. Hood Elevation
Tuesday Morning Snow Level
1000'
Tuesday Afternoon Snow Level
2000'
Tuesday Night Snow Level
2000'
Wednesday Morning Snow Level
2500'
(Easterly Flow *)
Wednesday Afternoon Snow Level
3000'
(Easterly Flow *)
Wednesday Night Snow Level
3000'
(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 0 - 0.50
Mt Baker Ski Area LT 0.25 1.00 - 1.50
Washington Pass LT 0.25 0.25 - 0.50
Stevens Pass 0 - 0.50 LT 0.25
Snoqualmie Pass 0.50 - 0.75 0.50 - 0.75
Mission Ridge LT 0.10 0 - 0.50
Crystal Mt LT 0.10 0.75 - 1.00
Paradise 0.25 - 0.50 1.00 - 1.50
White Pass LT 0.25 0.25 - 0.50
Mt Hood Meadows LT 0.25 0.75 - 1.00
LT 0.25 0 - 1.00

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Tuesday Morning WSW 20 - 30 SW 20 - 30 W 20 - 30 --- - W 15 - 25
Tuesday Afternoon WSW 20 - 30 SW 15 - 25 WSW 25 - 35 --- - W 20 - 30
Tuesday Night SW 10 - 20 SSW 10 - 20 WSW 15 - 25 --- - WSW 15 - 25
Wednesday Morning SSE 15 - 25 SSE 15 - 25 ESE 10 - 20 --- - SSW 15 - 25
Wednesday Afternoon SSE 25 - 35 ESE 25 - 35 ESE 20 - 30 --- - SSW 25 - 35
Hurricane Ridge Elevation
Tuesday Morning WSW 20 - 30
Tuesday Afternoon WSW 20 - 30
Tuesday Night SW 10 - 20
Wednesday Morning SSE 15 - 25
Wednesday Afternoon SSE 25 - 35
Wednesday Night SW 10 - 20
Mt. Baker Elevation
Tuesday Morning SW 20 - 30
Tuesday Afternoon SW 15 - 25
Tuesday Night SSW 10 - 20
Wednesday Morning SSE 15 - 25
Wednesday Afternoon ESE 25 - 35
Wednesday Night ESE 25 - 35
Stevens and Snoqualmie Pass Elevation
Tuesday Morning W 20 - 30
Tuesday Afternoon WSW 25 - 35
Tuesday Night WSW 15 - 25
Wednesday Morning ESE 10 - 20
Wednesday Afternoon ESE 20 - 30
Wednesday Night SSE 30 - 40
Mt. Rainier Elevation
Tuesday Morning --- -
Tuesday Afternoon --- -
Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night --- -
Mt. Hood Elevation
Tuesday Morning W 15 - 25
Tuesday Afternoon W 20 - 30
Tuesday Night WSW 15 - 25
Wednesday Morning SSW 15 - 25
Wednesday Afternoon SSW 25 - 35
Wednesday Night S 35 - 50
Hurricane Ridge Direction - Speed
Tuesday Morning WSW 20 - 30
Tuesday Afternoon WSW 20 - 30
Tuesday Night SW 10 - 20
Wednesday Morning SSE 15 - 25
Wednesday Afternoon SSE 25 - 35
Wednesday Night SW 10 - 20
Mt. Baker Direction - Speed
Tuesday Morning SW 20 - 30
Tuesday Afternoon SW 15 - 25
Tuesday Night SSW 10 - 20
Wednesday Morning SSE 15 - 25
Wednesday Afternoon ESE 25 - 35
Wednesday Night ESE 25 - 35
Stevens and Snoqualmie Pass Direction - Speed
Tuesday Morning W 20 - 30
Tuesday Afternoon WSW 25 - 35
Tuesday Night WSW 15 - 25
Wednesday Morning ESE 10 - 20
Wednesday Afternoon ESE 20 - 30
Wednesday Night SSE 30 - 40
Mt. Rainier Direction - Speed
Tuesday Morning --- -
Tuesday Afternoon --- -
Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night --- -
Mt. Hood Direction - Speed
Tuesday Morning W 15 - 25
Tuesday Afternoon W 20 - 30
Tuesday Night WSW 15 - 25
Wednesday Morning SSW 15 - 25
Wednesday Afternoon SSW 25 - 35
Wednesday Night S 35 - 50

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 Morning W 30 - 40 WSW 40 - 60 W 35 - 50 --- - NW 25 - 35
Tuesday Afternoon WSW 25 - 35 WSW 35 - 50 W 35 - 50 --- - NW 35 - 50
Tuesday Night W 20 - 30 W 20 - 30 W 30 - 40 --- - W 30 - 40
Wednesday Morning SSW 15 - 25 SSW 10 - 20 SSW 25 - 35 --- - SW 25 - 35
Wednesday Afternoon SSW 30 - 40 SSW 25 - 35 SW 35 - 50 --- - SW 35 - 50
Mt. Baker Direction - Speed
Tuesday Morning W 30 - 40
Tuesday Afternoon WSW 25 - 35
Tuesday Night W 20 - 30
Wednesday Morning SSW 15 - 25
Wednesday Afternoon SSW 30 - 40
Wednesday Night S 45 - 65
Washington Pass Direction - Speed
Tuesday Morning WSW 40 - 60
Tuesday Afternoon WSW 35 - 50
Tuesday Night W 20 - 30
Wednesday Morning SSW 10 - 20
Wednesday Afternoon SSW 25 - 35
Wednesday Night SSE 35 - 50
Stevens and Snoqualmie Pass Direction - Speed
Tuesday Morning W 35 - 50
Tuesday Afternoon W 35 - 50
Tuesday Night W 30 - 40
Wednesday Morning SSW 25 - 35
Wednesday Afternoon SW 35 - 50
Wednesday Night SSW 45 - 65
Mt. Rainier Direction - Speed
Tuesday Morning --- -
Tuesday Afternoon --- -
Tuesday Night --- -
Wednesday Morning --- -
Wednesday Afternoon --- -
Wednesday Night --- -
Mt. Hood Direction - Speed
Tuesday Morning NW 25 - 35
Tuesday Afternoon NW 35 - 50
Tuesday Night W 30 - 40
Wednesday Morning SW 25 - 35
Wednesday Afternoon SW 35 - 50
Wednesday Night SSW 50 - 70

Extended Weather Synopsis for Saturday night through Saturday

On Thursday, the closed low and upper trough will be gradually moving south and slightly east into our near shore waters, bringing a continued cooling trend along with an unstable air mass producing intermittent bands of energy and precipitation north and east across our region as the low pressure center spins offshore. Light to moderate southerly winds.

On Thursday night through Saturday, as the low drops south of our region, these bands will continue spiral around the low pressure and may result in patchy significant accumulations of snow over this period with other areas receiving very little snow and potentially and cool weather. Expect an overall drying trend during this period with southeast winds on Thursday night generally becoming light and variable Friday through Saturday.

 

Extended Weather

Olympics, Washington Cascades and Mt. Hood Area
Thursday Cool with cattered light to occasionally moderate bands of snow showers. Decreasing light to moderate southerly winds. Winds becoming southeast and then variable Thursday night. Friday Cool with periods of sun with scattered light to occasionally moderate bands of snow showers on Thursday. Partly clear with a chance of snow showers Thursday night. Light and variable winds throughout. Saturday Cool with a chance of some scattered moderate convective snow showers, particularly Saturday afternoon. Light and variable winds.

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Thursday Snow Level 1500' - 2500' 1500' - 2500' 2000' - 3000'
Thursday Night Snow Level 1500' - 2500' 1500' - 2500' 1000' - 2000'
Friday Snow Level 1500' - 2500' 1500' - 2500' 2000' - 3000'
Friday Night Snow Level 1000' - 2000' 1000' - 2000' 1000' - 2000'
Mt. Baker Elevation
Thursday Snow Level
1500' - 2500'
Thursday Night Snow Level
1500' - 2500'
Friday Snow Level
1500' - 2500'
Friday Night Snow Level
1000' - 2000'
Saturday Snow Level
1500' - 2500'
Snoqualmie Pass Elevation
Thursday Snow Level
1500' - 2500'
Thursday Night Snow Level
1500' - 2500'
Friday Snow Level
1500' - 2500'
Friday Night Snow Level
1000' - 2000'
Saturday Snow Level
1500' - 2500'
Mt. Hood Elevation
Thursday Snow Level
2000' - 3000'
Thursday Night Snow Level
1000' - 2000'
Friday Snow Level
2000' - 3000'
Friday Night Snow Level
1000' - 2000'
Saturday Snow Level
1500' - 2500'

* 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 Feb 27, 2018

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