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Weather Synopsis for Friday & Thursday
A longwave upper trough is digging off the California coast while dry northerly flow is seen aloft and at the surface over the PNW. The sensible weather effects can best be summarized as it's cold out there and the winds are relatively light. The cold weather station winner this morning on the NWAC network looks to be the Washington Pass base station (elev 5450 ft) checking in with -8F at 6 am. Low/mid clouds along the east slopes with ceilings in the 2500-4500 ft range are getting pulled through the Cascade Passes with weak easterly flow with only scattered mid level clouds elsewhere. By Friday afternoon generally sunny skies should be seen everywhere.
A weak upper level shortwave approaching in NW flow aloft will pass through the Washington Cascades Saturday. This will increase high clouds Friday night and moisture up to about crest level on Saturday. Expect mostly cloudy conditions along the west slopes with a few sunbreak holes mostly likely to poke out for the Mt. Baker area and the Olympics and decreasing cloud cover further east of the Cascade crest. A few light snow showers are likely on Saturday along the west slopes as well.
Warm frontal moisture also coming down in NW flow aloft will begin to nick the Olympics and north Cascades with light precipitation early Sunday morning. Temperatures will remain cold through the short term with snow/freezing levels near sea level.
Weather Forecast
Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
| Friday Morning |
Partly cloudy except mostly cloudy Cascade Passes. Cold. |
| Friday Afternoon |
Mostly sunny and cold. |
| Friday Night |
Mostly clear, then becoming mostly cloudy overnight with increasing mid and high clouds. |
| Saturday - Saturday Night |
Mostly cloudy with occasional light snow showers especially central and south Cascades. |
East slopes of the Washington Cascades
| Friday Morning |
Cloudy. Cold. |
| Friday Afternoon |
Becoming partly to mostly sunny. Cold. |
| Friday Night |
Mostly clear, then becoming partly to mostly cloudy overnight with increasing mid and high clouds. |
| Saturday - Saturday Night |
Mostly cloudy with occasional light snow showers near the Cascade crest but decreasing clouds and partly cloudy further east. |
Olympics
| Friday Morning |
Mostly clear except partly to mostly cloudy north slopes of the Olympics. Light to moderate NE winds. |
| Friday Afternoon |
Mostly sunny and cold. |
| Friday Night |
Mostly clear, then becoming mostly cloudy overnight with increasing mid and high clouds. |
| Saturday |
Mostly cloudy with occasional light snow showers mainly in the morning, becoming partly sunny Saturday afternoon. |
| Saturday Night |
Increasing clouds with light rain and snow developing late Saturday night. |
Mt. Hood Area
| Friday Morning |
Partly cloudy. Cold. |
| Friday Afternoon |
Mostly sunny and cold. |
| Friday Night |
Mostly clear, then becoming mostly cloudy overnight with increasing mid and high clouds. |
| Saturday - Saturday Night |
Mostly cloudy with a chance of very light snow showers. |
Issued: 7:12 AM PST Friday, December 16, 2016
Snow/Freezing Level (ft)
| Hurricane Ridge | Mt. Baker | Washington Pass | Leavenworth | Stevens Pass | Snoqualmie Pass | Mt. Rainier, Crystal & White Pass | Mt. Hood | ||
|---|---|---|---|---|---|---|---|---|---|
| Friday - Friday Night | Freezing Level | 0' | 0' | 0' | ' | ' | 0' | ' | 0' |
| Saturday - Saturday Night | Snow Level | 500' | 0' | 0' | ' | ' | 0' | ' | 500' |
| Hurricane Ridge | Elevation |
|---|---|
| Friday - Friday Night |
Freezing Level 0' |
| Saturday - Saturday Night |
Snow Level 500' |
| Mt. Baker | Elevation |
|---|---|
| Friday - Friday Night |
Freezing Level 0' |
| Saturday - Saturday Night |
Snow Level 0' |
| Washington Pass | Elevation |
|---|---|
| Friday - Friday Night |
Freezing Level 0' |
| Saturday - Saturday Night |
Snow Level 0' |
| Leavenworth | Elevation |
|---|---|
| Friday - Friday Night |
Freezing Level ' |
| Saturday - Saturday Night |
Snow Level ' |
| Stevens Pass | Elevation |
|---|---|
| Friday - Friday Night |
Freezing Level ' |
| Saturday - Saturday Night |
Snow Level ' |
| Snoqualmie Pass | Elevation |
|---|---|
| Friday - Friday Night |
Freezing Level 0' |
| Saturday - Saturday Night |
Snow Level 0' |
| Mt. Rainier & Crystal | Elevation |
|---|---|
| Friday - Friday Night |
Freezing Level ' |
| Saturday - Saturday Night |
Snow Level ' |
| Mt. Hood | Elevation |
|---|---|
| Friday - Friday Night |
Freezing Level 0' |
| Saturday - Saturday Night |
Snow Level 500' |
* 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: 7:12 AM PST Friday, December 16, 2016
Free Winds at 5000' (mph)
| Hurricane Ridge | Mt. Baker | Stevens to Snoqualmie Pass | Mt. Rainier | Mt. Hood | |
|---|---|---|---|---|---|
| Friday Morning | NE 10 - 20 | NE 5 - 15 | E 0 - 10 | --- - | E 0 - 10 |
| Friday Afternoon | N 0 - 10 | NE 0 - 10 | VAR 0 - 10 | --- - | VAR 0 - 10 |
| Friday Night - Saturday Morning | W 5 - 15 | W 0 - 10 | W 0 - 10 | --- - | W 5 - 15 |
| Saturday Afternoon - Saturday Night | NW 10 - 20 | VAR 0 - 10 | WNW 5 - 15 | --- - | WNW 10 - 20 |
| Hurricane Ridge | Elevation |
|---|---|
| Friday Morning | NE 10 - 20 |
| Friday Afternoon | N 0 - 10 |
| Friday Night - Saturday Morning | W 5 - 15 |
| Saturday Afternoon - Saturday Night | NW 10 - 20 |
| Mt. Baker | Elevation |
|---|---|
| Friday Morning | NE 5 - 15 |
| Friday Afternoon | NE 0 - 10 |
| Friday Night - Saturday Morning | W 0 - 10 |
| Saturday Afternoon - Saturday Night | VAR 0 - 10 |
| Stevens and Snoqualmie Pass | Elevation |
|---|---|
| Friday Morning | E 0 - 10 |
| Friday Afternoon | VAR 0 - 10 |
| Friday Night - Saturday Morning | W 0 - 10 |
| Saturday Afternoon - Saturday Night | WNW 5 - 15 |
| Mt. Rainier | Elevation |
|---|---|
| Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night - Saturday Morning | --- - |
| Saturday Afternoon - Saturday Night | --- - |
| Mt. Hood | Elevation |
|---|---|
| Friday Morning | E 0 - 10 |
| Friday Afternoon | VAR 0 - 10 |
| Friday Night - Saturday Morning | W 5 - 15 |
| Saturday Afternoon - Saturday Night | WNW 10 - 20 |
| Hurricane Ridge | Direction - Speed |
|---|---|
| Friday Morning | NE 10 - 20 |
| Friday Afternoon | N 0 - 10 |
| Friday Night - Saturday Morning | W 5 - 15 |
| Saturday Afternoon - Saturday Night | NW 10 - 20 |
| Mt. Baker | Direction - Speed |
|---|---|
| Friday Morning | NE 5 - 15 |
| Friday Afternoon | NE 0 - 10 |
| Friday Night - Saturday Morning | W 0 - 10 |
| Saturday Afternoon - Saturday Night | VAR 0 - 10 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Friday Morning | E 0 - 10 |
| Friday Afternoon | VAR 0 - 10 |
| Friday Night - Saturday Morning | W 0 - 10 |
| Saturday Afternoon - Saturday Night | WNW 5 - 15 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night - Saturday Morning | --- - |
| Saturday Afternoon - Saturday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Friday Morning | E 0 - 10 |
| Friday Afternoon | VAR 0 - 10 |
| Friday Night - Saturday Morning | W 5 - 15 |
| Saturday Afternoon - Saturday Night | WNW 10 - 20 |
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 | |
|---|---|---|---|---|---|
| Friday Morning | NNE 10 - 20 | N 15 - 25 | NNE 5 - 15 | --- - | N 5 - 15 |
| Friday Afternoon | N 10 - 20 | N 15 - 30 | N 15 - 25 | --- - | N 15 - 25 |
| Friday Night | NW 15 - 25 | NW 10 - 20 | NW 15 - 30 | --- - | NW 15 - 30 |
| Saturday - Saturday Night | NW 15 - 25 | NNW 15 - 25 | NW 20 - 35 | --- - | NW 20 - 30 |
| Mt. Baker | Direction - Speed |
|---|---|
| Friday Morning | NNE 10 - 20 |
| Friday Afternoon | N 10 - 20 |
| Friday Night | NW 15 - 25 |
| Saturday - Saturday Night | NW 15 - 25 |
| Washington Pass | Direction - Speed |
|---|---|
| Friday Morning | N 15 - 25 |
| Friday Afternoon | N 15 - 30 |
| Friday Night | NW 10 - 20 |
| Saturday - Saturday Night | NNW 15 - 25 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Friday Morning | NNE 5 - 15 |
| Friday Afternoon | N 15 - 25 |
| Friday Night | NW 15 - 30 |
| Saturday - Saturday Night | NW 20 - 35 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Saturday - Saturday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Friday Morning | N 5 - 15 |
| Friday Afternoon | N 15 - 25 |
| Friday Night | NW 15 - 30 |
| Saturday - Saturday 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.
Jump to: Weather Forecast I Snow/Freezing Level I Precipitation I Free Winds 5k I Free Winds 9k
Previous forecast from Dec 15, 2016
The NWAC program is administered by the USDA-Forest Service and operates from the National Weather Service Forecast Office in Seattle. NWAC services are made possible by important collaboration and support from a wide variety of federal, state and private cooperators.