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 & Thursday
A broad weather system passing through California and Oregon on Wednesday produced moderate snow for Mt. Hood with up to 12 inches of snow accumulating through early Thursday morning. Only very light amounts of snow clipped the south and central Washington Cascades. Easterly winds which were moderate from Mt. Hood up to Snoqualmie Pass Wednesday have eased and switched to light westerly above treeline on Thursday. This switch has allowed a 20 degree upward swing in temperature at the top of White Pass from Wednesday afternoon through Thursday afternoon.
An upper level trough will dig off the California coast through the short term period, turning the flow aloft more northerly. Leftover and isolated light showers Thursday morning should give way to a general clearing trend from north to south, although some clouds (low and mid-level clouds) may stay banked up along the east slopes and near the Cascade Passes in particular. Visible satellite shows the southern volcanoes in our area poking up above the clouds.
The Pacific Northwest will stay cold through the short term with some arctic air beginning to creep down the east slopes of the Cascades and through the Fraser Valley beginning Thursday night.
Friday looks like a fair weather day with cold temperatures, generally light winds and mostly sunny skies.
Weather Forecast
Olympics
| Thursday Afternoon |
Mostly sunny. |
| Thursday Night - Friday Morning |
Mostly clear, except becoming mostly cloudy overnight with very light snow showers developing along the north slopes of the Olympics. |
| Friday Afternoon |
Mostly sunny. |
| Friday Night |
Increasing high clouds overnight. |
Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
| Thursday Afternoon |
Becoming partly to mostly sunny. More clearing north Cascades and west of the Cascade Passes. . |
| Thursday Night |
Mostly clear except areas of low clouds and fog. |
| Friday |
Mostly sunny. |
| Friday Night |
Increasing high clouds overnight. |
East slopes of the Washington Cascades
| Thursday Afternoon |
Partly to mostly cloudy north Cascades, cloudy central and southeast Cascades. |
| Thursday Night |
Becoming partly cloudy overnight. Very cold NE Cascades. |
| Friday |
Mostly sunny. |
| Friday Night |
Increasing high clouds overnight. |
Mt. Hood Area
| Thursday Afternoon |
Becoming partly to mostly sunny. |
| Thursday Night |
Mostly clear. |
| Friday |
Mostly sunny. |
| Friday Night |
Increasing high clouds overnight. |
Issued: 2:09 PM PST Thursday, December 15, 2016
Snow/Freezing Level (ft)
| Hurricane Ridge | Mt. Baker | Washington Pass | Leavenworth | Stevens Pass | Snoqualmie Pass | Mt. Rainier, Crystal & White Pass | Mt. Hood | ||
|---|---|---|---|---|---|---|---|---|---|
| Thursday Afternoon | Snow Level * | 500' | 0' | 0' | ' | ' | 500' | ' | 1000' |
| Thursday Night - Friday Night | Freezing Level * | 0' | 0' | 0' | ' | ' | 0' | ' | 0' |
| Hurricane Ridge | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level 500' (Easterly Flow *) |
| Thursday Night - Friday Night |
Freezing Level 0' (Easterly Flow *) |
| Mt. Baker | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level 0' (Easterly Flow *) |
| Thursday Night - Friday Night |
Freezing Level 0' (Easterly Flow *) |
| Washington Pass | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level 0' (Easterly Flow *) |
| Thursday Night - Friday Night |
Freezing Level 0' (Easterly Flow *) |
| Leavenworth | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level ' (Easterly Flow *) |
| Thursday Night - Friday Night |
Freezing Level ' (Easterly Flow *) |
| Stevens Pass | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level ' (Easterly Flow *) |
| Thursday Night - Friday Night |
Freezing Level ' (Easterly Flow *) |
| Snoqualmie Pass | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level 500' (Easterly Flow *) |
| Thursday Night - Friday Night |
Freezing Level 0' (Easterly Flow *) |
| Mt. Rainier & Crystal | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level ' (Easterly Flow *) |
| Thursday Night - Friday Night |
Freezing Level ' (Easterly Flow *) |
| Mt. Hood | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level 1000' (Easterly Flow *) |
| Thursday Night - Friday Night |
Freezing Level 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.
Precipitation Forecast
| Thursday | Thursday | |
|---|---|---|
| Hurricane Ridge | LT 0.10 | LT 0.10 |
| Mt Baker Ski Area | LT 0.10 | LT 0.10 |
| Washington Pass | LT 0.10 | LT 0.10 |
| Stevens Pass | LT 0.10 | LT 0.10 |
| Snoqualmie Pass | LT 0.10 | LT 0.10 |
| Mission Ridge | LT 0.10 | LT 0.10 |
| Crystal Mt | LT 0.10 | LT 0.10 |
| Paradise | LT 0.10 | LT 0.10 |
| White Pass | LT 0.10 | LT 0.10 |
| Mt Hood Meadows | LT 0.10 | LT 0.10 |
| Timberline | LT 0.10 | 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: 2:09 PM PST Thursday, December 15, 2016
Free Winds at 5000' (mph)
| Hurricane Ridge | Mt. Baker | Stevens to Snoqualmie Pass | Mt. Rainier | Mt. Hood | |
|---|---|---|---|---|---|
| Thursday Afternoon | NE 0 - 10 | NE 0 - 10 | E 0 - 10 | --- - | W 5 - 15 |
| Thursday Night - Friday Morning | NE 5 - 15 | NE 10 - 20 | E 0 - 10 | --- - | NE 0 - 10 |
| Friday Afternoon | N 0 - 10 | NE 5 - 15 | VAR 0 - 10 | --- - | VAR 0 - 10 |
| Friday Night | W 5 - 15 | W 5 - 15 | W 5 - 15 | --- - | W 5 - 15 |
| Hurricane Ridge | Elevation |
|---|---|
| Thursday Afternoon | NE 0 - 10 |
| Thursday Night - Friday Morning | NE 5 - 15 |
| Friday Afternoon | N 0 - 10 |
| Friday Night | W 5 - 15 |
| Mt. Baker | Elevation |
|---|---|
| Thursday Afternoon | NE 0 - 10 |
| Thursday Night - Friday Morning | NE 10 - 20 |
| Friday Afternoon | NE 5 - 15 |
| Friday Night | W 5 - 15 |
| Stevens and Snoqualmie Pass | Elevation |
|---|---|
| Thursday Afternoon | E 0 - 10 |
| Thursday Night - Friday Morning | E 0 - 10 |
| Friday Afternoon | VAR 0 - 10 |
| Friday Night | W 5 - 15 |
| Mt. Rainier | Elevation |
|---|---|
| Thursday Afternoon | --- - |
| Thursday Night - Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Mt. Hood | Elevation |
|---|---|
| Thursday Afternoon | W 5 - 15 |
| Thursday Night - Friday Morning | NE 0 - 10 |
| Friday Afternoon | VAR 0 - 10 |
| Friday Night | W 5 - 15 |
| Hurricane Ridge | Direction - Speed |
|---|---|
| Thursday Afternoon | NE 0 - 10 |
| Thursday Night - Friday Morning | NE 5 - 15 |
| Friday Afternoon | N 0 - 10 |
| Friday Night | W 5 - 15 |
| Mt. Baker | Direction - Speed |
|---|---|
| Thursday Afternoon | NE 0 - 10 |
| Thursday Night - Friday Morning | NE 10 - 20 |
| Friday Afternoon | NE 5 - 15 |
| Friday Night | W 5 - 15 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | E 0 - 10 |
| Thursday Night - Friday Morning | E 0 - 10 |
| Friday Afternoon | VAR 0 - 10 |
| Friday Night | W 5 - 15 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Thursday Afternoon | --- - |
| Thursday Night - Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Thursday Afternoon | W 5 - 15 |
| Thursday Night - Friday Morning | NE 0 - 10 |
| Friday Afternoon | VAR 0 - 10 |
| Friday Night | W 5 - 15 |
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 | N 0 - 10 | N 0 - 10 | NNW 0 - 10 | --- - | W 10 - 20 |
| Thursday Night - Friday Morning | NNE 10 - 20 | N 15 - 25 | N 10 - 20 | --- - | N 10 - 20 |
| Friday Afternoon | N 10 - 20 | N 20 - 30 | N 15 - 30 | --- - | NNW 20 - 30 |
| Friday Night | NW 15 - 25 | NW 10 - 20 | NW 20 - 30 | --- - | NW 20 - 30 |
| Mt. Baker | Direction - Speed |
|---|---|
| Thursday Afternoon | N 0 - 10 |
| Thursday Night - Friday Morning | NNE 10 - 20 |
| Friday Afternoon | N 10 - 20 |
| Friday Night | NW 15 - 25 |
| Washington Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | N 0 - 10 |
| Thursday Night - Friday Morning | N 15 - 25 |
| Friday Afternoon | N 20 - 30 |
| Friday Night | NW 10 - 20 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | NNW 0 - 10 |
| Thursday Night - Friday Morning | N 10 - 20 |
| Friday Afternoon | N 15 - 30 |
| Friday Night | NW 20 - 30 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Thursday Afternoon | --- - |
| Thursday Night - Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Thursday Afternoon | W 10 - 20 |
| Thursday Night - Friday Morning | N 10 - 20 |
| Friday Afternoon | NNW 20 - 30 |
| Friday 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: 2:09 PM PST Thursday, December 15, 2016
Extended Weather Synopsis for Thursday night through Thursday
A weak upper trough coming down in Northwest flow aloft may bring some very light showers to the mountains on Saturday, although the main weather effect will be an increase of low and mid-level moisture directed into the west slopes.
On Sunday, warm frontal moisture streaming over the top of an upper level ridge located around 140 W will increase the amount of moisture over the area with light rain and snow developing Sunday morning mainly over the Olympics and north Cascades and beginning to spread south during the day. Mt. Hood may stay dry on Sunday. A gradual moderation of temperatures will begin Sunday and continue through Monday. By Monday afternoon, a cold front should come crashing through the PNW ushering in a stormy pattern through midweek.
Extended Weather
Olympics, Washington Cascades and Mt. Hood
Cloudy with chance of light snow showers Olympics, west slopes of the Cascades and Mt. Hood.
Cloudy with light rain and snow Olympics and north Cascades spreading south during the day.
Light rain and snow, except very light Mt. Hood. Gradual warming trend.
Light to moderate rain and snow.
Extended Snow/Freezing Levels
| Mt. Baker | Snoqualmie Pass | Mt. Hood | Easterly Flow * | ||
|---|---|---|---|---|---|
| Saturday - Saturday Night | Snow Level | 0' - 500' | 0' - 500' | 500' - 1500' | |
| Sunday | Snow Level | 1000' - 2000' | 1500' - 2500' | 2000' - 3000' | |
| Sunday Night - Monday | Snow Level | 2500' - 3500' | 3000' - 4000' | 3000' - 4000' |
| Mt. Baker | Elevation |
|---|---|
| Saturday - Saturday Night |
Snow Level 0' - 500' |
| Sunday |
Snow Level 1000' - 2000' |
| Sunday Night - Monday |
Snow Level 2500' - 3500' |
| Snoqualmie Pass | Elevation |
|---|---|
| Saturday - Saturday Night |
Snow Level 0' - 500' |
| Sunday |
Snow Level 1500' - 2500' |
| Sunday Night - Monday |
Snow Level 3000' - 4000' |
| Mt. Hood | Elevation |
|---|---|
| Saturday - Saturday Night |
Snow Level 500' - 1500' |
| Sunday |
Snow Level 2000' - 3000' |
| Sunday Night - Monday |
Snow Level 3000' - 4000' |
* 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 15, 2016
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