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 & Thursday
The strong upper level ridge anchored offshore near 145W has become flattened as a frontal wave currently E-W oriented over central British Columbia continues to sag south. High and mid clouds will filter into the forecast area from north to south today. Skies will become cloudy over the north Cascades by late morning and be accompanied by increasing crest level winds out of the west. The south Cascades including Mt. Hood should see mostly sunny skies for the better part of today. Out ahead of this frontal system, freezing levels are quite mild. Similar to the cloud forecast, there will be a north/south freezing level gradient over the region, with much warmer freezing levels realized in the south Cascades during the daylight hours.
The front will quickly pass through tonight with precipitation developing late this evening over the Olympics and Washington Cascades. Snow levels will fall rapidly as a sharp cool upper trough moves over the region by early Wednesday morning. Post-frontal snow showers are expected to linger longest in the central and southwest Cascades Wednesday afternoon, with skies becoming broken over the Olympics and north Cascades as the flow aloft turns more northerly. A quick 6-12 inches of snow is possible for the west slopes of the Cascades and Mt. Hood from this system with lower snowfall totals expected for the Olympics and the east slopes of the Cascades.
The upper level ridge will amplify offshore Wednesday night and shower activity will quickly taper down as the trough shifts into the Intermountain West.
Weather Forecast
Olympics
| Tuesday | Mostly clear with increasing high and mid clouds during the day, becoming cloudy by afternoon. |
| Tuesday Night | Light snow developing in the evening. Rapid cooling. |
| Wednesday | Light to occasionally moderate snow showers becoming scattered showers with broken skies in the afternoon. |
| Wednesday Night | Mostly cloudy with isolated light snow showers. |
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
| Tuesday | Mostly clear this morning with increasing high and mid clouds during the day, becoming cloudy north Cascades and partly sunny south Cascades. Increasing crest level winds north and central Cascades in the afternoon. Milder south Cascades. |
| Tuesday Night | Light snow developing in the late evening and spreading south. Light snow becoming occasionally moderate after midnight. Rapid cooling. |
| Wednesday | Light to moderate snow showers becoming lighter in the afternoon except showers becoming scattered with broken skies north Cascades in the afternoon. |
| Wednesday Night | Mostly cloudy with isolated light snow showers. |
East Slopes of the Washington Cascades
| Tuesday | Mostly clear this morning with increasing high and mid clouds during the day, becoming cloudy northeast Cascades and partly sunny southeast Cascades. Increasing crest level winds northeast and central-east Cascades in the afternoon. Milder central-east and southeast Cascades. |
| Tuesday Night | Light snow developing in the late evening and spreading south overnight. Rapid cooling. |
| Wednesday | Light snow showers in the morning becoming scattered showers with broken skies in the afternoon. |
| Wednesday Night | Partly to mostly cloudy. |
Mt. Hood
| Tuesday | Mostly clear this morning, becoming partly sunny in the afternoon with increasing high clouds. Mild. |
| Tuesday Night | Light snow developing after midnight. Rapid cooling. Increasing winds late. |
| Wednesday | Light to moderate snow showers becoming lighter in the afternoon. Windy. |
| Wednesday Night | Mostly cloudy with isolated light snow showers. |
Issued: 3:04 PM PST Tuesday, February 13, 2018
Snow/Freezing Level (ft)
| Hurricane Ridge | Mt. Baker | Washington Pass | Leavenworth | Stevens Pass | Snoqualmie Pass | Mt. Rainier, Crystal & White Pass | Mt. Hood | ||
|---|---|---|---|---|---|---|---|---|---|
| Tuesday Afternoon | Freezing Level | 7000' | 4000' | 5000' | ' | ' | 6500' | ' | 9500' |
| Tuesday Night | Snow Level | 3000' | 2000' | 2500' | ' | ' | 2500' | ' | 3000' |
| Wednesday | Snow Level | 2000' | 1500' | 2000' | ' | ' | 2000' | ' | 2500' |
| Wednesday Night | Snow Level | 1500' | 1000' | 1000' | ' | ' | 1000' | ' | 1500' |
| Hurricane Ridge | Elevation |
|---|---|
| Tuesday Afternoon |
Freezing Level 7000' |
| Tuesday Night |
Snow Level 3000' |
| Wednesday |
Snow Level 2000' |
| Wednesday Night |
Snow Level 1500' |
| Mt. Baker | Elevation |
|---|---|
| Tuesday Afternoon |
Freezing Level 4000' |
| Tuesday Night |
Snow Level 2000' |
| Wednesday |
Snow Level 1500' |
| Wednesday Night |
Snow Level 1000' |
| Washington Pass | Elevation |
|---|---|
| Tuesday Afternoon |
Freezing Level 5000' |
| Tuesday Night |
Snow Level 2500' |
| Wednesday |
Snow Level 2000' |
| Wednesday Night |
Snow Level 1000' |
| Leavenworth | Elevation |
|---|---|
| Tuesday Afternoon |
Freezing Level ' |
| Tuesday Night |
Snow Level ' |
| Wednesday |
Snow Level ' |
| Wednesday Night |
Snow Level ' |
| Stevens Pass | Elevation |
|---|---|
| Tuesday Afternoon |
Freezing Level ' |
| Tuesday Night |
Snow Level ' |
| Wednesday |
Snow Level ' |
| Wednesday Night |
Snow Level ' |
| Snoqualmie Pass | Elevation |
|---|---|
| Tuesday Afternoon |
Freezing Level 6500' |
| Tuesday Night |
Snow Level 2500' |
| Wednesday |
Snow Level 2000' |
| Wednesday Night |
Snow Level 1000' |
| Mt. Rainier & Crystal | Elevation |
|---|---|
| Tuesday Afternoon |
Freezing Level ' |
| Tuesday Night |
Snow Level ' |
| Wednesday |
Snow Level ' |
| Wednesday Night |
Snow Level ' |
| Mt. Hood | Elevation |
|---|---|
| Tuesday Afternoon |
Freezing Level 9500' |
| Tuesday Night |
Snow Level 3000' |
| Wednesday |
Snow Level 2500' |
| 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
| Thursday | Thursday | |
|---|---|---|
| Hurricane Ridge | LT 0.25 | LT 0.25 |
| Mt Baker Ski Area | 0.25 - 0.50 | LT 0.25 |
| Washington Pass | LT 0.25 | LT 0.25 |
| Stevens Pass | 0.25 - 0.50 | 0 - 0.50 |
| Snoqualmie Pass | 0.25 - 0.50 | 0 - 0.50 |
| Mission Ridge | LT 0.10 | LT 0.10 |
| Crystal Mt | LT 0.10 | LT 0.25 |
| Paradise | 0.25 - 0.50 | 0 - 0.50 |
| White Pass | LT 0.25 | LT 0.25 |
| Mt Hood Meadows | LT 0.10 | 0.75 - 1.00 |
| Timberline | LT 0.10 | 0 - 1.00 |
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: 3:04 PM PST Tuesday, February 13, 2018
Free Winds at 5000' (mph)
| Hurricane Ridge | Mt. Baker | Stevens to Snoqualmie Pass | Mt. Rainier | Mt. Hood | |
|---|---|---|---|---|---|
| Tuesday Afternoon | SW 5 - 15 | SW 5 - 15 | SW 5 - 15 | --- - | SW 5 - 15 |
| Tuesday Night | SW 15 - 25 | SW 10 - 20 | SW 15 - 30 | --- - | SW 15 - 25 |
| Wednesday Morning | WNW 10 - 20 | NW 0 - 10 | SW 10 - 20 | --- - | W 20 - 30 |
| Wednesday Afternoon | NW 0 - 10 | NW 0 - 10 | WNW 10 - 20 | --- - | W 20 - 30 |
| Wednesday Night | W 0 - 10 | W 0 - 10 | WNW 5 - 15 | --- - | W 15 - 25 |
| Hurricane Ridge | Elevation |
|---|---|
| Tuesday Afternoon | SW 5 - 15 |
| Tuesday Night | SW 15 - 25 |
| Wednesday Morning | WNW 10 - 20 |
| Wednesday Afternoon | NW 0 - 10 |
| Wednesday Night | W 0 - 10 |
| Mt. Baker | Elevation |
|---|---|
| Tuesday Afternoon | SW 5 - 15 |
| Tuesday Night | SW 10 - 20 |
| Wednesday Morning | NW 0 - 10 |
| Wednesday Afternoon | NW 0 - 10 |
| Wednesday Night | W 0 - 10 |
| Stevens and Snoqualmie Pass | Elevation |
|---|---|
| Tuesday Afternoon | SW 5 - 15 |
| Tuesday Night | SW 15 - 30 |
| Wednesday Morning | SW 10 - 20 |
| Wednesday Afternoon | WNW 10 - 20 |
| Wednesday Night | WNW 5 - 15 |
| Mt. Rainier | Elevation |
|---|---|
| Tuesday Afternoon | --- - |
| Tuesday Night | --- - |
| Wednesday Morning | --- - |
| Wednesday Afternoon | --- - |
| Wednesday Night | --- - |
| Mt. Hood | Elevation |
|---|---|
| Tuesday Afternoon | SW 5 - 15 |
| Tuesday Night | SW 15 - 25 |
| Wednesday Morning | W 20 - 30 |
| Wednesday Afternoon | W 20 - 30 |
| Wednesday Night | W 15 - 25 |
| Hurricane Ridge | Direction - Speed |
|---|---|
| Tuesday Afternoon | SW 5 - 15 |
| Tuesday Night | SW 15 - 25 |
| Wednesday Morning | WNW 10 - 20 |
| Wednesday Afternoon | NW 0 - 10 |
| Wednesday Night | W 0 - 10 |
| Mt. Baker | Direction - Speed |
|---|---|
| Tuesday Afternoon | SW 5 - 15 |
| Tuesday Night | SW 10 - 20 |
| Wednesday Morning | NW 0 - 10 |
| Wednesday Afternoon | NW 0 - 10 |
| Wednesday Night | W 0 - 10 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Tuesday Afternoon | SW 5 - 15 |
| Tuesday Night | SW 15 - 30 |
| Wednesday Morning | SW 10 - 20 |
| Wednesday Afternoon | WNW 10 - 20 |
| Wednesday Night | WNW 5 - 15 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Tuesday Afternoon | --- - |
| Tuesday Night | --- - |
| Wednesday Morning | --- - |
| Wednesday Afternoon | --- - |
| Wednesday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Tuesday Afternoon | SW 5 - 15 |
| Tuesday Night | SW 15 - 25 |
| Wednesday Morning | W 20 - 30 |
| Wednesday Afternoon | W 20 - 30 |
| Wednesday 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 | |
|---|---|---|---|---|---|
| Tuesday Afternoon | WSW 30 - 40 | WSW 35 - 45 | WSW 25 - 35 | --- - | W 10 - 20 |
| Tuesday Night | WSW 25 - 35 | W 25 - 35 | WSW 30 - 40 | --- - | W 40 - 50 |
| Wednesday Morning | NW 5 - 15 | NW 10 - 20 | NW 15 - 30 | --- - | W 40 - 50 |
| Wednesday Afternoon | NW 5 - 15 | NW 10 - 20 | NW 15 - 30 | --- - | WNW 30 - 40 |
| Wednesday Night | NW 10 - 20 | NW 15 - 25 | NW 25 - 35 | --- - | NW 20 - 30 |
| Mt. Baker | Direction - Speed |
|---|---|
| Tuesday Afternoon | WSW 30 - 40 |
| Tuesday Night | WSW 25 - 35 |
| Wednesday Morning | NW 5 - 15 |
| Wednesday Afternoon | NW 5 - 15 |
| Wednesday Night | NW 10 - 20 |
| Washington Pass | Direction - Speed |
|---|---|
| Tuesday Afternoon | WSW 35 - 45 |
| Tuesday Night | W 25 - 35 |
| Wednesday Morning | NW 10 - 20 |
| Wednesday Afternoon | NW 10 - 20 |
| Wednesday Night | NW 15 - 25 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Tuesday Afternoon | WSW 25 - 35 |
| Tuesday Night | WSW 30 - 40 |
| Wednesday Morning | NW 15 - 30 |
| Wednesday Afternoon | NW 15 - 30 |
| Wednesday Night | NW 25 - 35 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Tuesday Afternoon | --- - |
| Tuesday Night | --- - |
| Wednesday Morning | --- - |
| Wednesday Afternoon | --- - |
| Wednesday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Tuesday Afternoon | W 10 - 20 |
| Tuesday Night | W 40 - 50 |
| Wednesday Morning | W 40 - 50 |
| Wednesday Afternoon | WNW 30 - 40 |
| Wednesday Night | NW 20 - 30 |
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: 3:04 PM PST Tuesday, February 13, 2018
Extended Weather Synopsis for Thursday night through Thursday
The story of NW flow aloft over the region continues through the extended period, with the mean position of the Pacific Ridge offshore deciding how much snow levels will rise with Friday's and Saturday's weather systems.
Thursday will be a relative break in the otherwise active pattern expected over much of the holiday weekend, with plenty of moisture trapped along the west slopes of the Cascades and continued cool temperatures leading to a cloudy forecast with light snow showers. Areas further east and south will have a better chance of sunbreaks.
A low pressure system upstream and off the northern tip of Vancouver Island Thursday night will quickly spread light snow over the Olympics and Cascades as it drops SE toward the region. The upper level ridge will have amplified Thursday and should shift slightly closer to the coast Friday and Saturday. This will lift the jet stream into British Columbia and allow some warming to take place Friday afternoon. A second and stronger system arriving Saturday looks to maintain the same snow levels but with the potential for heavier precipitation and stronger winds, especially for the northwest and central-west Cascades. Ensemble forecasts for Friday/Saturday suggest some uncertainty to how much snow levels will rise during this period.
Extended Weather
Olympics, Washington Cascades and Mt. Hood Area
Extended Snow/Freezing Levels
| Mt. Baker | Snoqualmie Pass | Mt. Hood | Easterly Flow * | ||
|---|---|---|---|---|---|
| Thursday | Snow Level | 1000' - 2000' | 1500' - 2500' | 1500' - 2500' | |
| Thursday Night | Snow Level | 500' - 1500' | 1500' - 2500' | 2000' - 3000' | |
| Friday | Snow Level | 2500' - 3500' | 3500' - 4500' | 4000' - 5000' | |
| Friday Night | Snow Level | 3000' - 4000' | 3500' - 4500' | 5000' - 6000' | |
| Saturday | Snow Level | 3500' - 4500' | 4000' - 5000' | 5000' - 6000' |
| Mt. Baker | Elevation |
|---|---|
| Thursday |
Snow Level 1000' - 2000' |
| Thursday Night |
Snow Level 500' - 1500' |
| Friday |
Snow Level 2500' - 3500' |
| Friday Night |
Snow Level 3000' - 4000' |
| Saturday |
Snow Level 3500' - 4500' |
| Snoqualmie Pass | Elevation |
|---|---|
| Thursday |
Snow Level 1500' - 2500' |
| Thursday Night |
Snow Level 1500' - 2500' |
| Friday |
Snow Level 3500' - 4500' |
| Friday Night |
Snow Level 3500' - 4500' |
| Saturday |
Snow Level 4000' - 5000' |
| Mt. Hood | Elevation |
|---|---|
| Thursday |
Snow Level 1500' - 2500' |
| Thursday Night |
Snow Level 2000' - 3000' |
| Friday |
Snow Level 4000' - 5000' |
| Friday Night |
Snow Level 5000' - 6000' |
| Saturday |
Snow Level 5000' - 6000' |
* 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 13, 2018
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