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Weather Synopsis for Thursday & Thursday
Our persistent upper ridge and warm airmass has returned to its full glory and will bring us one more day of unseasonably warm weather aloft. A surface high pressure located east of the Cascades will continue to support offshore flow across the Cascades today. Inversion conditions will continue to cause areas of low clouds and cooler temperatures at lower elevations east of the crest and through the Cascade passes.
On Thursday night, a weak cold front and shortwave ridge will continue to flatten our ridge and will be arriving on our coastline by morning.
A shortwave and associated weakening cold front will pass the Olympics and Cascades during the mid-morning hours with SW flow aloft switching to WNW behind the front.
Weather Forecast
Olympics
| Thursday |
Increasing high clouds. |
| Thursday Night |
High clouds lowering late with increasing light to moderate rain by morning. |
| Friday |
Light to moderate rain and snow in the morning becoming decreasing light to moderate rain and snow showers in the afternoon. |
| Friday Night |
Mostly cloudy. |
Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
| Thursday |
Increasing high clouds. Low clouds and cooler in the passes, mainly Snoqualmie. |
| Thursday Night |
Increasing high clouds with lower-level clouds arriving by morning. Cooler with low clouds all night in the passes, mainly Snoqualmie. |
| Friday |
Increasing light to moderate rain, snow and areas of freezing rain initially in deep valleys and passes. Precipitation starts early in the north and moves south as the morning progresses, bringing 3-6 hours of precipitation to most locations before becoming light to moderate rain and snow showers by afternoon, with the afternoon precipitation heaviest in the central part. |
| Friday Night |
Lingering light rain and snow showers, mainly central part. |
Mt. Hood Area
| Thursday |
Increasing high clouds. |
| Thursday Night |
Increasing high clouds lowering toward morning. |
| Friday |
Increasing rain and snow starting mid-morning becoming light rain and snow showers by evening. |
| Friday Night |
Decreasing light snow showers. |
Stevens, Snoqualmie, and White Passes
| Thursday |
Increasing high clouds. Low clouds at lower elevations with the inversion. |
| Thursday Night |
Increasing high clouds with lower-level clouds arriving by morning. Low clouds at lower elevations with the inversion. |
| Friday |
Increasing light to moderate rain, snow or freezing rain initially changing to all snow. Precipitation starts early in the north and moves south as the morning progresses, bringing 3-6 hours of precipitation to most locations before becoming light snow showers by afternoon, with the afternoon precipitation heaviest in the central part. |
| Friday Night |
Lingering light snow showers, mainly central part higher elevations. |
Issued: 7:43 AM PST Thursday, December 14, 2017
Snow/Freezing Level (ft)
| Hurricane Ridge | Mt. Baker | Washington Pass | Leavenworth | Stevens Pass | Snoqualmie Pass | Mt. Rainier, Crystal & White Pass | Mt. Hood | ||
|---|---|---|---|---|---|---|---|---|---|
| Thursday Afternoon | Freezing Level * | 11500' | 11500' | 12000' | ' | ' | 12500' | ' | 13000' |
| Friday Morning | Snow Level | 4000' | 3500' | 4000' | ' | ' | 4000' | ' | 6000' |
| Thursday Morning | Freezing Level * | 12500' | 12000' | 12000' | ' | ' | 12500' | ' | 13500' |
| Thursday Night | Snow Level * | 6500' | 5500' | 6500' | ' | ' | 8000' | ' | 10500' |
| Friday Afternoon | Snow Level | 3000' | 2500' | 3000' | ' | ' | 3000' | ' | 3000' |
| Friday Night | Snow Level | 2500' | 1500' | 1500' | ' | ' | 2000' | ' | 2000' |
| Hurricane Ridge | Elevation |
|---|---|
| Thursday Afternoon |
Freezing Level 11500' (Easterly Flow *) |
| Friday Morning |
Snow Level 4000' |
| Thursday Morning |
Freezing Level 12500' (Easterly Flow *) |
| Thursday Night |
Snow Level 6500' (Easterly Flow *) |
| Friday Afternoon |
Snow Level 3000' |
| Friday Night |
Snow Level 2500' |
| Mt. Baker | Elevation |
|---|---|
| Thursday Afternoon |
Freezing Level 11500' (Easterly Flow *) |
| Friday Morning |
Snow Level 3500' |
| Thursday Morning |
Freezing Level 12000' (Easterly Flow *) |
| Thursday Night |
Snow Level 5500' (Easterly Flow *) |
| Friday Afternoon |
Snow Level 2500' |
| Friday Night |
Snow Level 1500' |
| Washington Pass | Elevation |
|---|---|
| Thursday Afternoon |
Freezing Level 12000' (Easterly Flow *) |
| Friday Morning |
Snow Level 4000' |
| Thursday Morning |
Freezing Level 12000' (Easterly Flow *) |
| Thursday Night |
Snow Level 6500' (Easterly Flow *) |
| Friday Afternoon |
Snow Level 3000' |
| Friday Night |
Snow Level 1500' |
| Leavenworth | Elevation |
|---|---|
| Thursday Afternoon |
Freezing Level ' (Easterly Flow *) |
| Friday Morning |
Snow Level ' |
| Thursday Morning |
Freezing Level ' (Easterly Flow *) |
| Thursday Night |
Snow Level ' (Easterly Flow *) |
| Friday Afternoon |
Snow Level ' |
| Friday Night |
Snow Level ' |
| Stevens Pass | Elevation |
|---|---|
| Thursday Afternoon |
Freezing Level ' (Easterly Flow *) |
| Friday Morning |
Snow Level ' |
| Thursday Morning |
Freezing Level ' (Easterly Flow *) |
| Thursday Night |
Snow Level ' (Easterly Flow *) |
| Friday Afternoon |
Snow Level ' |
| Friday Night |
Snow Level ' |
| Snoqualmie Pass | Elevation |
|---|---|
| Thursday Afternoon |
Freezing Level 12500' (Easterly Flow *) |
| Friday Morning |
Snow Level 4000' |
| Thursday Morning |
Freezing Level 12500' (Easterly Flow *) |
| Thursday Night |
Snow Level 8000' (Easterly Flow *) |
| Friday Afternoon |
Snow Level 3000' |
| Friday Night |
Snow Level 2000' |
| Mt. Rainier & Crystal | Elevation |
|---|---|
| Thursday Afternoon |
Freezing Level ' (Easterly Flow *) |
| Friday Morning |
Snow Level ' |
| Thursday Morning |
Freezing Level ' (Easterly Flow *) |
| Thursday Night |
Snow Level ' (Easterly Flow *) |
| Friday Afternoon |
Snow Level ' |
| Friday Night |
Snow Level ' |
| Mt. Hood | Elevation |
|---|---|
| Thursday Afternoon |
Freezing Level 13000' (Easterly Flow *) |
| Friday Morning |
Snow Level 6000' |
| Thursday Morning |
Freezing Level 13500' (Easterly Flow *) |
| Thursday Night |
Snow Level 10500' (Easterly Flow *) |
| Friday Afternoon |
Snow Level 3000' |
| Friday Night |
Snow Level 2000' |
* 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 | 0.25 - 0.50 |
| Mt Baker Ski Area | LT 0.10 | 0.25 - 0.50 |
| Washington Pass | LT 0.10 | LT 0.25 |
| Stevens Pass | LT 0.10 | 0.25 - 0.50 |
| Snoqualmie Pass | LT 0.10 | 0.25 - 0.50 |
| Mission Ridge | LT 0.10 | LT 0.10 |
| Crystal Mt | LT 0.10 | 0.25 - 0.50 |
| Paradise | LT 0.10 | 0.25 - 0.50 |
| White Pass | LT 0.10 | LT 0.25 |
| Mt Hood Meadows | LT 0.10 | LT 0.25 |
| Timberline | LT 0.10 | LT 0.25 |
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: 7:43 AM PST Thursday, December 14, 2017
Free Winds at 5000' (mph)
| Hurricane Ridge | Mt. Baker | Stevens to Snoqualmie Pass | Mt. Rainier | Mt. Hood | |
|---|---|---|---|---|---|
| Thursday Afternoon | WSW 10 - 15 | SSW 5 - 10 | VAR 0 - 10 | --- - | S 5 - 10 |
| Friday Morning | W 15 - 20 | SW 10 - 15 | W 10 - 15 | --- - | WSW 20 - 25 |
| Thursday Morning | WSW 5 - 10 | N 0 - 10 | ESE 5 - 10 | --- - | ESE 10 - 15 |
| Thursday Night | WSW 10 - 15 | WSW 5 - 10 | W 10 - 15 | --- - | WSW 15 - 20 |
| Friday Afternoon | W 20 - 25 | W 15 - 20 | W 15 - 20 | --- - | W 25 - 30 |
| Friday Night | W 20 - 25 | WSW 10 - 15 | W 15 - 20 | --- - | WNW 25 - 30 |
| Hurricane Ridge | Elevation |
|---|---|
| Thursday Afternoon | WSW 10 - 15 |
| Friday Morning | W 15 - 20 |
| Thursday Morning | WSW 5 - 10 |
| Thursday Night | WSW 10 - 15 |
| Friday Afternoon | W 20 - 25 |
| Friday Night | W 20 - 25 |
| Mt. Baker | Elevation |
|---|---|
| Thursday Afternoon | SSW 5 - 10 |
| Friday Morning | SW 10 - 15 |
| Thursday Morning | N 0 - 10 |
| Thursday Night | WSW 5 - 10 |
| Friday Afternoon | W 15 - 20 |
| Friday Night | WSW 10 - 15 |
| Stevens and Snoqualmie Pass | Elevation |
|---|---|
| Thursday Afternoon | VAR 0 - 10 |
| Friday Morning | W 10 - 15 |
| Thursday Morning | ESE 5 - 10 |
| Thursday Night | W 10 - 15 |
| Friday Afternoon | W 15 - 20 |
| Friday Night | W 15 - 20 |
| Mt. Rainier | Elevation |
|---|---|
| Thursday Afternoon | --- - |
| Friday Morning | --- - |
| Thursday Morning | --- - |
| Thursday Night | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Mt. Hood | Elevation |
|---|---|
| Thursday Afternoon | S 5 - 10 |
| Friday Morning | WSW 20 - 25 |
| Thursday Morning | ESE 10 - 15 |
| Thursday Night | WSW 15 - 20 |
| Friday Afternoon | W 25 - 30 |
| Friday Night | WNW 25 - 30 |
| Hurricane Ridge | Direction - Speed |
|---|---|
| Thursday Afternoon | WSW 10 - 15 |
| Friday Morning | W 15 - 20 |
| Thursday Morning | WSW 5 - 10 |
| Thursday Night | WSW 10 - 15 |
| Friday Afternoon | W 20 - 25 |
| Friday Night | W 20 - 25 |
| Mt. Baker | Direction - Speed |
|---|---|
| Thursday Afternoon | SSW 5 - 10 |
| Friday Morning | SW 10 - 15 |
| Thursday Morning | N 0 - 10 |
| Thursday Night | WSW 5 - 10 |
| Friday Afternoon | W 15 - 20 |
| Friday Night | WSW 10 - 15 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | VAR 0 - 10 |
| Friday Morning | W 10 - 15 |
| Thursday Morning | ESE 5 - 10 |
| Thursday Night | W 10 - 15 |
| Friday Afternoon | W 15 - 20 |
| Friday Night | W 15 - 20 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Thursday Afternoon | --- - |
| Friday Morning | --- - |
| Thursday Morning | --- - |
| Thursday Night | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Thursday Afternoon | S 5 - 10 |
| Friday Morning | WSW 20 - 25 |
| Thursday Morning | ESE 10 - 15 |
| Thursday Night | WSW 15 - 20 |
| Friday Afternoon | W 25 - 30 |
| Friday Night | WNW 25 - 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.
Free Winds at 9000' (mph)
| Mt. Baker | Washington Pass | Stevens to Snoqualmie Pass | Mt. Rainier | Mt. Hood | |
|---|---|---|---|---|---|
| Thursday Morning | WNW 10 - 15 | WNW 5 - 15 | WNW 15 - 20 | --- - | WNW 10 - 15 |
| Thursday Afternoon | W 20 - 25 | WSW 20 - 25 | W 20 - 25 | --- - | WNW 15 - 20 |
| Thursday Night | WSW 30 - 40 | WSW 35 - 50 | WSW 40 - 55 | --- - | WSW 25 - 30 |
| Friday Morning | W 20 - 25 | W 20 - 25 | W 25 - 35 | --- - | WSW 35 - 50 |
| Friday Afternoon | W 15 - 20 | W 20 - 30 | W 30 - 40 | --- - | W 40 - 55 |
| Friday Night | W 25 - 35 | W 20 - 25 | WNW 40 - 55 | --- - | NW 45 - 65 |
| Mt. Baker | Direction - Speed |
|---|---|
| Thursday Morning | WNW 10 - 15 |
| Thursday Afternoon | W 20 - 25 |
| Thursday Night | WSW 30 - 40 |
| Friday Morning | W 20 - 25 |
| Friday Afternoon | W 15 - 20 |
| Friday Night | W 25 - 35 |
| Washington Pass | Direction - Speed |
|---|---|
| Thursday Morning | WNW 5 - 15 |
| Thursday Afternoon | WSW 20 - 25 |
| Thursday Night | WSW 35 - 50 |
| Friday Morning | W 20 - 25 |
| Friday Afternoon | W 20 - 30 |
| Friday Night | W 20 - 25 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Thursday Morning | WNW 15 - 20 |
| Thursday Afternoon | W 20 - 25 |
| Thursday Night | WSW 40 - 55 |
| Friday Morning | W 25 - 35 |
| Friday Afternoon | W 30 - 40 |
| Friday Night | WNW 40 - 55 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Thursday Morning | --- - |
| Thursday Afternoon | --- - |
| Thursday Night | --- - |
| Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Thursday Morning | WNW 10 - 15 |
| Thursday Afternoon | WNW 15 - 20 |
| Thursday Night | WSW 25 - 30 |
| Friday Morning | WSW 35 - 50 |
| Friday Afternoon | W 40 - 55 |
| Friday Night | NW 45 - 65 |
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 13, 2017
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.