Jump to: Weather Forecast I Snow/Freezing Level I Precipitation I Free Winds 5k I Free Winds 9k I Extended Weather
Weather Synopsis for Thursday & Sunday
Afternoon update: Many areas have been nudged lower for Day 1 Precipitation Forecast ending 4 am Friday.
Warm frontal moisture will continue to ride over flat upper level ridging that is centered over the Pacific Northwest today. This will mean continuing light rain and snow for the north Cascades and Olympics with decreasing clouds and precipitation further south. There is a large north to south snow level gradient over our region as well, with much milder temperatures expected down in Oregon.
The frontal boundary will quickly sag south this evening, producing a period of moderate to heavy precipitation especially for the west slopes of the central Cascades. There will be a slight warming trend today, especially for the south Washington Cascades and Mt. Hood. A shift from east to west winds should allow snow levels to bump up to 3500 feet for Snoqualmie Pass area this evening with precipitation. A brief period of strong westerly winds should accompany the frontal passage late this afternoon and evening while winds decrease for areas like Mt. Baker that saw strong pre-frontal winds during the day. Showers should continue overnight in a period of NW flow, with perhaps a convergence zone forming downwind of Vancouver Island.
The trailing longwave trough will swing through the area on Friday, keeping the air mass unstable enough to support scattered showers mainly along the west slopes of the Cascades in the morning. By the afternoon northerly flow should help dry us out with sunshine expected. Weak ridging will flop over the area Friday night as we continue our break between weather systems.
Weather Forecast
Olympics
| Thursday Afternoon |
Light to occasionally moderate rain and snow transitioning to showers. Windy. Cooling trend late. |
| Thursday Night |
Mostly cloudy with light rain and snow showers. Cooler. |
| Friday |
Becoming mostly sunny with isolated showers in the morning. |
| Friday Night |
Mostly clear. |
Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
| Thursday Afternoon - Thursday Evening |
Moderate rain and snow north part. Light rain and snow developing south part. Winds increasing. Slight warming trend. |
| Thursday Night |
Light to moderate showers. Cooling trend. |
| Friday |
Mostly cloudy with scattered light snow showers in the morning becoming mostly sunny in the afternoon. Cooler. |
| Friday Night |
Mostly clear. |
East slopes of the Washington Cascades
| Thursday Afternoon - Evening |
Light to moderate rain and snow north part. Light rain and snow developing south part. Winds increasing. Slight warming trend. |
| Thursday Night |
Mostly cloudy with light showers. Windy. Cooling trend. |
| Friday |
Partly cloudy with isolated showers in the morning becoming mostly sunny. |
| Friday Night |
Mostly clear. |
Mt. Hood Area
| Thursday |
Partly cloudy. Mild. |
| Thursday Night |
Light rain and snow developing and transitioning to light showers late overnight. Windy. Cooling trend late. |
| Friday |
Partly to mostly cloudy with scattered light snow showers in the morning becoming mostly sunny in the afternoon. Cooler. |
| Friday Night |
Mostly clear. |
Issued: 2:34 PM PST Thursday, December 29, 2016
Snow/Freezing Level (ft)
| Hurricane Ridge | Mt. Baker | Washington Pass | Leavenworth | Stevens Pass | Snoqualmie Pass | Mt. Rainier, Crystal & White Pass | Mt. Hood | ||
|---|---|---|---|---|---|---|---|---|---|
| Thursday Mid-day | Snow Level * | 4500' | 3000' | 2000' | ' | ' | 3000' | ' | 7000' |
| Thursday Afternoon | Snow Level * | 3000' | 2500' | 2500' | ' | ' | 3000' | ' | 6000' |
| Thursday Evening | Snow Level | 2000' | 2000' | 2000' | ' | ' | 3500' | ' | 5500' |
| Thursday Night - Friday | Snow Level | 1500' | 1500' | 500' | ' | ' | 1500' | ' | 2000' |
| Friday Night | Freezing Level | 1500' | 500' | 0' | ' | ' | 500' | ' | 1500' |
| Hurricane Ridge | Elevation |
|---|---|
| Thursday Mid-day |
Snow Level 4500' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level 3000' (Easterly Flow *) |
| Thursday Evening |
Snow Level 2000' |
| Thursday Night - Friday |
Snow Level 1500' |
| Friday Night |
Freezing Level 1500' |
| Mt. Baker | Elevation |
|---|---|
| Thursday Mid-day |
Snow Level 3000' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level 2500' (Easterly Flow *) |
| Thursday Evening |
Snow Level 2000' |
| Thursday Night - Friday |
Snow Level 1500' |
| Friday Night |
Freezing Level 500' |
| Washington Pass | Elevation |
|---|---|
| Thursday Mid-day |
Snow Level 2000' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level 2500' (Easterly Flow *) |
| Thursday Evening |
Snow Level 2000' |
| Thursday Night - Friday |
Snow Level 500' |
| Friday Night |
Freezing Level 0' |
| Leavenworth | Elevation |
|---|---|
| Thursday Mid-day |
Snow Level ' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level ' (Easterly Flow *) |
| Thursday Evening |
Snow Level ' |
| Thursday Night - Friday |
Snow Level ' |
| Friday Night |
Freezing Level ' |
| Stevens Pass | Elevation |
|---|---|
| Thursday Mid-day |
Snow Level ' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level ' (Easterly Flow *) |
| Thursday Evening |
Snow Level ' |
| Thursday Night - Friday |
Snow Level ' |
| Friday Night |
Freezing Level ' |
| Snoqualmie Pass | Elevation |
|---|---|
| Thursday Mid-day |
Snow Level 3000' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level 3000' (Easterly Flow *) |
| Thursday Evening |
Snow Level 3500' |
| Thursday Night - Friday |
Snow Level 1500' |
| Friday Night |
Freezing Level 500' |
| Mt. Rainier & Crystal | Elevation |
|---|---|
| Thursday Mid-day |
Snow Level ' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level ' (Easterly Flow *) |
| Thursday Evening |
Snow Level ' |
| Thursday Night - Friday |
Snow Level ' |
| Friday Night |
Freezing Level ' |
| Mt. Hood | Elevation |
|---|---|
| Thursday Mid-day |
Snow Level 7000' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level 6000' (Easterly Flow *) |
| Thursday Evening |
Snow Level 5500' |
| Thursday Night - Friday |
Snow Level 2000' |
| Friday Night |
Freezing 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
| Sunday | Sunday | |
|---|---|---|
| Hurricane Ridge | 0 - 0.50 | LT 0.10 |
| Mt Baker Ski Area | 0 - 1.00 | LT 0.10 |
| Washington Pass | 0.50 - 0.75 | LT 0.10 |
| Stevens Pass | 1.00 - 1.50 | LT 0.10 |
| Snoqualmie Pass | 0 - 1.00 | LT 0.10 |
| Mission Ridge | LT 0.25 | LT 0.10 |
| Crystal Mt | LT 0.25 | LT 0.10 |
| Paradise | 0 - 0.50 | LT 0.10 |
| White Pass | 0.25 - 0.50 | LT 0.10 |
| Mt Hood Meadows | LT 0.25 | LT 0.10 |
| Timberline | LT 0.25 | LT 0.10 |
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: 2:34 PM PST Thursday, December 29, 2016
Free Winds at 5000' (mph)
| Hurricane Ridge | Mt. Baker | Stevens to Snoqualmie Pass | Mt. Rainier | Mt. Hood | |
|---|---|---|---|---|---|
| Thursday Afternoon | W 20 - 30 | SW 20 - 35 | SW 25 - 45 | --- - | WSW 15 - 25 |
| Thursday Night | NW 15 - 25 | W 10 - 20 | W 15 - 25 | --- - | W 25 - 35 |
| Friday | N 0 - 10 | NW 0 - 10 | NW 5 - 15 | --- - | NW 10 - 20 |
| Friday Night | W 0 - 10 | W 0 - 10 | W 0 - 10 | --- - | NW 0 - 10 |
| Hurricane Ridge | Elevation |
|---|---|
| Thursday Afternoon | W 20 - 30 |
| Thursday Night | NW 15 - 25 |
| Friday | N 0 - 10 |
| Friday Night | W 0 - 10 |
| Mt. Baker | Elevation |
|---|---|
| Thursday Afternoon | SW 20 - 35 |
| Thursday Night | W 10 - 20 |
| Friday | NW 0 - 10 |
| Friday Night | W 0 - 10 |
| Stevens and Snoqualmie Pass | Elevation |
|---|---|
| Thursday Afternoon | SW 25 - 45 |
| Thursday Night | W 15 - 25 |
| Friday | NW 5 - 15 |
| Friday Night | W 0 - 10 |
| Mt. Rainier | Elevation |
|---|---|
| Thursday Afternoon | --- - |
| Thursday Night | --- - |
| Friday | --- - |
| Friday Night | --- - |
| Mt. Hood | Elevation |
|---|---|
| Thursday Afternoon | WSW 15 - 25 |
| Thursday Night | W 25 - 35 |
| Friday | NW 10 - 20 |
| Friday Night | NW 0 - 10 |
| Hurricane Ridge | Direction - Speed |
|---|---|
| Thursday Afternoon | W 20 - 30 |
| Thursday Night | NW 15 - 25 |
| Friday | N 0 - 10 |
| Friday Night | W 0 - 10 |
| Mt. Baker | Direction - Speed |
|---|---|
| Thursday Afternoon | SW 20 - 35 |
| Thursday Night | W 10 - 20 |
| Friday | NW 0 - 10 |
| Friday Night | W 0 - 10 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | SW 25 - 45 |
| Thursday Night | W 15 - 25 |
| Friday | NW 5 - 15 |
| Friday Night | W 0 - 10 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Thursday Afternoon | --- - |
| Thursday Night | --- - |
| Friday | --- - |
| Friday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Thursday Afternoon | WSW 15 - 25 |
| Thursday Night | W 25 - 35 |
| Friday | NW 10 - 20 |
| Friday Night | NW 0 - 10 |
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 | |
|---|---|---|---|---|---|
| Thursday Afternoon | SW 40 - 50 | SW 50 - 60 | WSW 50 - 60 | --- - | WSW 50 - 60 |
| Thursday Night | W 20 - 30 | W 30 - 40 | W 30 - 50 | --- - | WSW 50 - 60 |
| Friday - Friday Night | N 10 - 20 | N 10 - 20 | NW 15 - 25 | --- - | N 15 - 25 |
| Mt. Baker | Direction - Speed |
|---|---|
| Thursday Afternoon | SW 40 - 50 |
| Thursday Night | W 20 - 30 |
| Friday - Friday Night | N 10 - 20 |
| Washington Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | SW 50 - 60 |
| Thursday Night | W 30 - 40 |
| Friday - Friday Night | N 10 - 20 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | WSW 50 - 60 |
| Thursday Night | W 30 - 50 |
| Friday - Friday Night | NW 15 - 25 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Thursday Afternoon | --- - |
| Thursday Night | --- - |
| Friday - Friday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Thursday Afternoon | WSW 50 - 60 |
| Thursday Night | WSW 50 - 60 |
| Friday - Friday Night | N 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.
Issued: 2:34 PM PST Thursday, December 29, 2016
Extended Weather Synopsis for Sunday night through Sunday
A weather system will race down from the NW on Saturday, bringing a quick shot of precipitation to the area that begins Saturday afternoon and continues through the New Year. Alpine winds will quickly ramp up Saturday afternoon as the front sweeps south.
A weak low pressure system set up off the Washington Coast Sunday may produce some light showers for the southwest and central-west Cascades with some light upslope showers possible over the east slopes. The main story will be the arctic air mass that begins to work over to the west side of the Cascade crest late Sunday and becomes entrenched through Tuesday. Scattered showers should wind down Sunday night and moderate easterly flow may develop on Monday as the high pressure sliding down from British Columbia helps to reinforce the cold air over the PNW.
Extended Weather
Olympics, Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
Mostly cloudy north and central Cascades and the Olympics. Mostly sunny south Washington Cascades and Mt. Hood.
Light rain and snow developing from north to south over the Cascades and Olympics. Mostly cloudy at Mt. Hood. Alpine winds increasing.
Light snow showers tapering down with a clearing trend Sunday from north to south.
Clear and cold.
Extended Snow/Freezing Levels
| Mt. Baker | Snoqualmie Pass | Mt. Hood | Easterly Flow * | ||
|---|---|---|---|---|---|
| Saturday | Snow Level | 0' - 1000' | 1000' - 2000' | 1500' - 2500' | |
| Saturday Night - Sunday Morning | Snow Level | 0' - 500' | 500' - 1500' | 1000' - 2000' | |
| Sunday - Monday | Freezing Level | 0' - 0' | 0' - 0' | 0' - 0' | * |
| Mt. Baker | Elevation |
|---|---|
| Saturday |
Snow Level 0' - 1000' |
| Saturday Night - Sunday Morning |
Snow Level 0' - 500' |
| Sunday - Monday |
Freezing Level 0' - 0' (Easterly Flow *) |
| Snoqualmie Pass | Elevation |
|---|---|
| Saturday |
Snow Level 1000' - 2000' |
| Saturday Night - Sunday Morning |
Snow Level 500' - 1500' |
| Sunday - Monday |
Freezing Level 0' - 0' (Easterly Flow *) |
| Mt. Hood | Elevation |
|---|---|
| Saturday |
Snow Level 1500' - 2500' |
| Saturday Night - Sunday Morning |
Snow Level 1000' - 2000' |
| Sunday - Monday |
Freezing Level 0' - 0' (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.
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 29, 2016
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