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 & Friday
Afternoon update: Precipitation forecasts for Day 1 have been adjusted downward, heavier precipitation still expected overnight through Monday morning. Snowfall totals through 2 PM Sunday have been light to non-existent due to warmer than expected temperatures and lighter precipitation totals.
The upper ridge that led to a long period of dry weather over the Pacific Northwest has been temporarily flattened as the polar jet takes aim at southern British Columbia through the short term period. This will open the door to warm frontal moisture in strong westerly flow aloft. Light to moderate precipitation should affect the west slopes of the Olympics and central and northern Washington Cascades today, with precipitation amounts falling off sharply to the south and east today. A warming trend will eventually overwhelm weak easterly flow in the Cascade Passes; Snoqualmie is expected to change to rain by mid-day while Stevens Pass should hold off until mid-late afternoon.
The frontal boundary will finally shift south Sunday night through Monday morning, bringing some moderate precipitation to the SW Cascades including the Paradise area. Crystal mountain looks to be fairly blocked in this pattern with much lower totals. A slight cooling trend will take place late Sunday night through Monday, but snow levels for the southern Washington Cascades and Mt. Hood area should stay on the mild side throughout the short term. The other main weather factor will be strong W-SW winds which are expected to increase Sunday afternoon and stay strong through Monday morning.
Precipitation should temporarily ease off Monday afternoon before another potent storm system approaching in westerly flow begins to renew moderate precipitation late Monday night.
Weather Forecast
Olympics
| Sunday | Periods of light rain and snow. Mild. |
| Sunday Night | Light rain and snow. Slight cooling trend. |
| Monday | Light rain and snow tapering off in the afternoon. Cooler. |
| Monday Night | Rain and snow increasing overnight and becoming moderate. |
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
| Sunday | Light rain and snow developing in the morning and increasing during the afternoon, becoming moderate central Cascades. Warming trend. |
| Sunday Night | Light to moderate rain and snow, locally heavier Stevens and Snoqualmie Passes. Milder. Windy. |
| Monday | Moderate rain and snow, heaviest central and south Cascades, becoming light in the afternoon. Slow cooling trend. |
| Monday Night | Rain and snow increasing overnight and becoming moderate. |
East Slopes of the Washington Cascades
| Sunday | Light rain and snow except light to occasionally moderate central-east Cascades near the Cascade crest. Slow warming trend. |
| Sunday Night | Light rain and snow, locally moderate central-east Cascades near the Cascade crest. Milder. Windy. |
| Monday | Light rain and snow, tapering off in the afternoon from north to south. Slow cooling trend. |
| Monday Night | Light rain and snow developing and increasing overnight. |
Mt. Hood
| Sunday | Periods of light rain and snow. Mild. |
| Sunday Night | Periods of light rain and snow. Mild. |
| Monday | Light to occasionally moderate rain and snow. Mild. |
| Monday Night | Periods of light rain and snow. Slight cooling trend late. |
Issued: 3:02 PM PST Sunday, December 17, 2017
Snow/Freezing Level (ft)
| Hurricane Ridge | Mt. Baker | Washington Pass | Leavenworth | Stevens Pass | Snoqualmie Pass | Mt. Rainier, Crystal & White Pass | Mt. Hood | ||
|---|---|---|---|---|---|---|---|---|---|
| Sunday Afternoon | Snow Level | 6500' | 4500' | 4000' | ' | ' | 5500' | ' | 7000' |
| Sunday Night | Snow Level | 6000' | 4500' | 4500' | ' | ' | 5500' | ' | 6000' |
| Monday Morning | Snow Level | 4500' | 3500' | 4000' | ' | ' | 4500' | ' | 6000' |
| Monday Afternoon | Snow Level | 3000' | 2500' | 2500' | ' | ' | 3500' | ' | 6000' |
| Monday Night | Snow Level * | 3500' | 2500' | 2500' | ' | ' | 4000' | ' | 5500' |
| Hurricane Ridge | Elevation |
|---|---|
| Sunday Afternoon |
Snow Level 6500' |
| Sunday Night |
Snow Level 6000' |
| Monday Morning |
Snow Level 4500' |
| Monday Afternoon |
Snow Level 3000' |
| Monday Night |
Snow Level 3500' (Easterly Flow *) |
| Mt. Baker | Elevation |
|---|---|
| Sunday Afternoon |
Snow Level 4500' |
| Sunday Night |
Snow Level 4500' |
| Monday Morning |
Snow Level 3500' |
| Monday Afternoon |
Snow Level 2500' |
| Monday Night |
Snow Level 2500' (Easterly Flow *) |
| Washington Pass | Elevation |
|---|---|
| Sunday Afternoon |
Snow Level 4000' |
| Sunday Night |
Snow Level 4500' |
| Monday Morning |
Snow Level 4000' |
| Monday Afternoon |
Snow Level 2500' |
| Monday Night |
Snow Level 2500' (Easterly Flow *) |
| Leavenworth | Elevation |
|---|---|
| Sunday Afternoon |
Snow Level ' |
| Sunday Night |
Snow Level ' |
| Monday Morning |
Snow Level ' |
| Monday Afternoon |
Snow Level ' |
| Monday Night |
Snow Level ' (Easterly Flow *) |
| Stevens Pass | Elevation |
|---|---|
| Sunday Afternoon |
Snow Level ' |
| Sunday Night |
Snow Level ' |
| Monday Morning |
Snow Level ' |
| Monday Afternoon |
Snow Level ' |
| Monday Night |
Snow Level ' (Easterly Flow *) |
| Snoqualmie Pass | Elevation |
|---|---|
| Sunday Afternoon |
Snow Level 5500' |
| Sunday Night |
Snow Level 5500' |
| Monday Morning |
Snow Level 4500' |
| Monday Afternoon |
Snow Level 3500' |
| Monday Night |
Snow Level 4000' (Easterly Flow *) |
| Mt. Rainier & Crystal | Elevation |
|---|---|
| Sunday Afternoon |
Snow Level ' |
| Sunday Night |
Snow Level ' |
| Monday Morning |
Snow Level ' |
| Monday Afternoon |
Snow Level ' |
| Monday Night |
Snow Level ' (Easterly Flow *) |
| Mt. Hood | Elevation |
|---|---|
| Sunday Afternoon |
Snow Level 7000' |
| Sunday Night |
Snow Level 6000' |
| Monday Morning |
Snow Level 6000' |
| Monday Afternoon |
Snow Level 6000' |
| Monday Night |
Snow Level 5500' (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
| Friday | Friday | |
|---|---|---|
| Hurricane Ridge | 0.25 - 0.50 | 0 - 1.00 |
| Mt Baker Ski Area | 1.00 - 1.50 | 0 - 0.75 |
| Washington Pass | 0 - 0.50 | 0.50 - 0.75 |
| Stevens Pass | 1.50 - 2.00 | 1.00 - 1.50 |
| Snoqualmie Pass | 2.00 - 2.50 | 0 - 1.50 |
| Mission Ridge | LT 0.25 | 0.25 - 0.50 |
| Crystal Mt | LT 0.25 | 0 - 0.75 |
| Paradise | 1.00 - 1.50 | 0 - 2.00 |
| White Pass | 0.25 - 0.50 | 0 - 1.00 |
| Mt Hood Meadows | LT 0.10 | 0 - 0.50 |
| Timberline | LT 0.25 | 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: 3:02 PM PST Sunday, December 17, 2017
Free Winds at 5000' (mph)
| Hurricane Ridge | Mt. Baker | Stevens to Snoqualmie Pass | Mt. Rainier | Mt. Hood | |
|---|---|---|---|---|---|
| Sunday Afternoon | WSW 20 - 30 | SW 15 - 25 | SW 25 - 35 | --- - | W 10 - 20 |
| Sunday Night | WSW 15 - 25 | WSW 20 - 30 | SW 30 - 50 | --- - | SW 20 - 30 |
| Monday Morning | WSW 15 - 25 | WSW 15 - 25 | WSW 15 - 30 | --- - | WSW 25 - 35 |
| Monday Afternoon | W 5 - 15 | WSW 5 - 15 | WSW 10 - 20 | --- - | SW 20 - 30 |
| Monday Night | S 25 - 35 | SE 5 - 15 | SW 20 - 30 | --- - | SW 25 - 35 |
| Hurricane Ridge | Elevation |
|---|---|
| Sunday Afternoon | WSW 20 - 30 |
| Sunday Night | WSW 15 - 25 |
| Monday Morning | WSW 15 - 25 |
| Monday Afternoon | W 5 - 15 |
| Monday Night | S 25 - 35 |
| Mt. Baker | Elevation |
|---|---|
| Sunday Afternoon | SW 15 - 25 |
| Sunday Night | WSW 20 - 30 |
| Monday Morning | WSW 15 - 25 |
| Monday Afternoon | WSW 5 - 15 |
| Monday Night | SE 5 - 15 |
| Stevens and Snoqualmie Pass | Elevation |
|---|---|
| Sunday Afternoon | SW 25 - 35 |
| Sunday Night | SW 30 - 50 |
| Monday Morning | WSW 15 - 30 |
| Monday Afternoon | WSW 10 - 20 |
| Monday Night | SW 20 - 30 |
| Mt. Rainier | Elevation |
|---|---|
| Sunday Afternoon | --- - |
| Sunday Night | --- - |
| Monday Morning | --- - |
| Monday Afternoon | --- - |
| Monday Night | --- - |
| Mt. Hood | Elevation |
|---|---|
| Sunday Afternoon | W 10 - 20 |
| Sunday Night | SW 20 - 30 |
| Monday Morning | WSW 25 - 35 |
| Monday Afternoon | SW 20 - 30 |
| Monday Night | SW 25 - 35 |
| Hurricane Ridge | Direction - Speed |
|---|---|
| Sunday Afternoon | WSW 20 - 30 |
| Sunday Night | WSW 15 - 25 |
| Monday Morning | WSW 15 - 25 |
| Monday Afternoon | W 5 - 15 |
| Monday Night | S 25 - 35 |
| Mt. Baker | Direction - Speed |
|---|---|
| Sunday Afternoon | SW 15 - 25 |
| Sunday Night | WSW 20 - 30 |
| Monday Morning | WSW 15 - 25 |
| Monday Afternoon | WSW 5 - 15 |
| Monday Night | SE 5 - 15 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Sunday Afternoon | SW 25 - 35 |
| Sunday Night | SW 30 - 50 |
| Monday Morning | WSW 15 - 30 |
| Monday Afternoon | WSW 10 - 20 |
| Monday Night | SW 20 - 30 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Sunday Afternoon | --- - |
| Sunday Night | --- - |
| Monday Morning | --- - |
| Monday Afternoon | --- - |
| Monday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Sunday Afternoon | W 10 - 20 |
| Sunday Night | SW 20 - 30 |
| Monday Morning | WSW 25 - 35 |
| Monday Afternoon | SW 20 - 30 |
| Monday Night | SW 25 - 35 |
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 | WSW 35 - 45 | WSW 40 - 50 | W 40 - 50 | --- - | W 45 - 55 |
| Sunday Night | WSW 40 - 50 | W 50 - 60 | WSW 40 - 55 | --- - | W 45 - 55 |
| Monday Morning | WSW 30 - 40 | W 45 - 55 | W 45 - 60 | --- - | W 45 - 55 |
| Monday Afternoon | WSW 25 - 35 | W 35 - 45 | WSW 45 - 55 | --- - | W 35 - 45 |
| Monday Night | SW 25 - 35 | SW 25 - 35 | SW 40 - 50 | --- - | SW 40 - 50 |
| Mt. Baker | Direction - Speed |
|---|---|
| Sunday Afternoon | WSW 35 - 45 |
| Sunday Night | WSW 40 - 50 |
| Monday Morning | WSW 30 - 40 |
| Monday Afternoon | WSW 25 - 35 |
| Monday Night | SW 25 - 35 |
| Washington Pass | Direction - Speed |
|---|---|
| Sunday Afternoon | WSW 40 - 50 |
| Sunday Night | W 50 - 60 |
| Monday Morning | W 45 - 55 |
| Monday Afternoon | W 35 - 45 |
| Monday Night | SW 25 - 35 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Sunday Afternoon | W 40 - 50 |
| Sunday Night | WSW 40 - 55 |
| Monday Morning | W 45 - 60 |
| Monday Afternoon | WSW 45 - 55 |
| Monday Night | SW 40 - 50 |
| 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 | W 45 - 55 |
| Monday Morning | W 45 - 55 |
| Monday Afternoon | W 35 - 45 |
| Monday Night | SW 40 - 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.
Issued: 3:02 PM PST Sunday, December 17, 2017
Extended Weather Synopsis for Friday night through Friday
Our sudden jump into an active pattern continues with another frontal wave developing in strong westerly flow aloft and approaching our region Monday night into Tuesday. A strong surface low will develop this time as the associated upper level trough digs off the Pacific coast on Tuesday, orienting the frontal boundary more N-S than the last system. Heavy precipitation will develop out ahead of the front with strong SW winds, especially in the alpine. There will be a warming trend that peaks mid-afternoon/early evening although snow levels do not look quite as high as the Sunday/Sunday night system.
The front will pass through the Cascades early Tuesday evening with sharp cooling and showers behind. Showers should quickly diminish on Wednesday as the upper level ridge amplifies offshore and the flow aloft turns northerly. Thursday currently looks dry but clouds out ahead of an approaching shortwave trough in NW flow aloft may spread over the area by the afternoon.
Extended Weather
Olympics, Washington Cascades and Mt. Hood Area
Extended Snow/Freezing Levels
| Mt. Baker | Snoqualmie Pass | Mt. Hood | Easterly Flow * | ||
|---|---|---|---|---|---|
| Tuesday | Snow Level | 3000' - 4000' | 4000' - 5000' | 5000' - 6000' | * |
| Tuesday Night | Snow Level | 1500' - 2500' | 2000' - 3000' | 2500' - 3500' | |
| Wednesday | Freezing Level | 0' - 1000' | 500' - 1500' | 1500' - 2500' | |
| Wednesday Night | Freezing Level | 0' - 1000' | 500' - 1500' | 500' - 1500' | |
| Thursday | Freezing Level | 1000' - 2000' | 500' - 1500' | 1500' - 2500' |
| Mt. Baker | Elevation |
|---|---|
| Tuesday |
Snow Level 3000' - 4000' (Easterly Flow *) |
| Tuesday Night |
Snow Level 1500' - 2500' |
| Wednesday |
Freezing Level 0' - 1000' |
| Wednesday Night |
Freezing Level 0' - 1000' |
| Thursday |
Freezing Level 1000' - 2000' |
| Snoqualmie Pass | Elevation |
|---|---|
| Tuesday |
Snow Level 4000' - 5000' (Easterly Flow *) |
| Tuesday Night |
Snow Level 2000' - 3000' |
| Wednesday |
Freezing Level 500' - 1500' |
| Wednesday Night |
Freezing Level 500' - 1500' |
| Thursday |
Freezing Level 500' - 1500' |
| Mt. Hood | Elevation |
|---|---|
| Tuesday |
Snow Level 5000' - 6000' (Easterly Flow *) |
| Tuesday Night |
Snow Level 2500' - 3500' |
| Wednesday |
Freezing Level 1500' - 2500' |
| Wednesday Night |
Freezing Level 500' - 1500' |
| Thursday |
Freezing 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 Dec 17, 2017
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