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 & Monday
A cool upper level trough is passing through the PNW today. Daytime heating and the cool air mass overhead will help increase shower activity and coverage this afternoon. The air mass is marginally unstable and a rogue thundershower can't be ruled out. Showers should quickly taper off overnight, except for a Puget Sound Convergence Zone expected to form near and north of the Stevens Pass area. Slightly higher accumulations are possible in this area.
The big news is that an entire day of dryness and relative warmth is on tap for Friday. A high amplitude upper level ridge will move over the entire West Coast on Friday. After some morning clouds, freezing levels should rise into the 7000-9000 ft range over the Olympics and Cascades. As has been the case with dry weather forecasts as of late, there are a few caveats. The next approaching frontal system should start to spread some high cloud over the area from the SW in the afternoon. Also, offshore gradients will increase though the Passes.
As the front nears the Washington Coast late Friday night, Pass level offshore winds will become moderate as well as crest level E-SE winds particularly in the southern/central Washington Cascades and Mt. Hood area. Mid and high level clouds will increase Friday night.
Weather Forecast
Olympics, Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
| Thursday Afternoon |
Cloudy with light to occasionally moderate rain and snow showers. Slight chance of a thunderstorm. |
| Thursday Night |
Light rain and snow showers tapering off and becoming mostly cloudy overnight. |
| Friday |
Partly cloudy in the morning, becoming mostly sunny by late morning. Warmer. High clouds increasing Friday afternoon. |
| Friday Night |
Becoming mostly cloudy with increasing mid and high clouds. Breezy E-SE Pass level winds and crest level winds southwest/central-west Cascades. |
Mt. Hood Area
| Thursday Afternoon |
Cloudy with light to occasionally moderate rain and snow showers. Slight chance of a thunderstorm. |
| Thursday Night |
Light rain and snow showers tapering off and becoming mostly cloudy overnight. |
| Friday |
Partly cloudy in the morning, becoming mostly sunny by late morning. Warmer. High clouds increasing Friday afternoon. |
| Friday Night |
Becoming mostly cloudy with increasing mid and high clouds. |
East slopes of the Washington Cascades
| Thursday Afternoon |
Mostly cloudy with light rain and snow showers, except occasionally moderate near the Cascade crest. Slight chance of a thunderstorm. Partly cloudy further east. |
| Thursday Night |
Light rain and snow showers tapering off in the evening and becoming partly to mostly clear overnight. |
| Friday |
Mostly sunny. Warmer. High clouds increasing Friday afternoon. |
| Friday Night |
Becoming partly to mostly cloudy with increasing mid and high clouds. |
Issued: 1:58 PM PDT Thursday, April 20, 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 - Thursday Night | Snow Level | 5000' | 4500' | 5000' | ' | ' | 4500' | ' | 5500' |
| Friday Morning | Freezing Level | 4000' | 3500' | 3500' | ' | ' | 3000' | ' | 4000' |
| Friday Afternoon - Friday Night | Freezing Level * | 7500' | 7500' | 7000' | ' | ' | 7500' | ' | 8500' |
| Hurricane Ridge | Elevation |
|---|---|
| Thursday Afternoon - Thursday Night |
Snow Level 5000' |
| Friday Morning |
Freezing Level 4000' |
| Friday Afternoon - Friday Night |
Freezing Level 7500' (Easterly Flow *) |
| Mt. Baker | Elevation |
|---|---|
| Thursday Afternoon - Thursday Night |
Snow Level 4500' |
| Friday Morning |
Freezing Level 3500' |
| Friday Afternoon - Friday Night |
Freezing Level 7500' (Easterly Flow *) |
| Washington Pass | Elevation |
|---|---|
| Thursday Afternoon - Thursday Night |
Snow Level 5000' |
| Friday Morning |
Freezing Level 3500' |
| Friday Afternoon - Friday Night |
Freezing Level 7000' (Easterly Flow *) |
| Leavenworth | Elevation |
|---|---|
| Thursday Afternoon - Thursday Night |
Snow Level ' |
| Friday Morning |
Freezing Level ' |
| Friday Afternoon - Friday Night |
Freezing Level ' (Easterly Flow *) |
| Stevens Pass | Elevation |
|---|---|
| Thursday Afternoon - Thursday Night |
Snow Level ' |
| Friday Morning |
Freezing Level ' |
| Friday Afternoon - Friday Night |
Freezing Level ' (Easterly Flow *) |
| Snoqualmie Pass | Elevation |
|---|---|
| Thursday Afternoon - Thursday Night |
Snow Level 4500' |
| Friday Morning |
Freezing Level 3000' |
| Friday Afternoon - Friday Night |
Freezing Level 7500' (Easterly Flow *) |
| Mt. Rainier & Crystal | Elevation |
|---|---|
| Thursday Afternoon - Thursday Night |
Snow Level ' |
| Friday Morning |
Freezing Level ' |
| Friday Afternoon - Friday Night |
Freezing Level ' (Easterly Flow *) |
| Mt. Hood | Elevation |
|---|---|
| Thursday Afternoon - Thursday Night |
Snow Level 5500' |
| Friday Morning |
Freezing Level 4000' |
| Friday Afternoon - Friday Night |
Freezing Level 8500' (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
| Monday | Monday | |
|---|---|---|
| Hurricane Ridge | LT 0.25 | LT 0.10 |
| Mt Baker Ski Area | 0.25 - 0.50 | LT 0.10 |
| Washington Pass | LT 0.10 | LT 0.10 |
| Stevens Pass | 0.25 - 0.50 | LT 0.10 |
| Snoqualmie Pass | 0.25 - 0.50 | LT 0.10 |
| Mission Ridge | LT 0.10 | LT 0.10 |
| Crystal Mt | LT 0.25 | LT 0.10 |
| Paradise | 0 - 0.50 | LT 0.10 |
| White Pass | LT 0.25 | LT 0.10 |
| Mt Hood Meadows | LT 0.25 | LT 0.10 |
| Timberline | 0.25 - 0.50 | 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: 1:58 PM PDT Thursday, April 20, 2017
Free Winds at 5000' (mph)
| Hurricane Ridge | Mt. Baker | Stevens to Snoqualmie Pass | Mt. Rainier | Mt. Hood | |
|---|---|---|---|---|---|
| Thursday Afternoon | W 0 - 10 | WSW 0 - 10 | WSW 5 - 15 | --- - | W 15 - 25 |
| Thursday Night - Friday Morning | E 0 - 10 | VAR 0 - 10 | W 0 - 10 | --- - | W 5 - 15 |
| Friday Afternoon | SE 5 - 15 | E 5 - 15 | ESE 10 - 20 | --- - | ESE 15 - 25 |
| Friday Night | SE 10 - 20 | E 5 - 15 | ESE 20 - 35 | --- - | SE 15 - 25 |
| Hurricane Ridge | Elevation |
|---|---|
| Thursday Afternoon | W 0 - 10 |
| Thursday Night - Friday Morning | E 0 - 10 |
| Friday Afternoon | SE 5 - 15 |
| Friday Night | SE 10 - 20 |
| Mt. Baker | Elevation |
|---|---|
| Thursday Afternoon | WSW 0 - 10 |
| Thursday Night - Friday Morning | VAR 0 - 10 |
| Friday Afternoon | E 5 - 15 |
| Friday Night | E 5 - 15 |
| Stevens and Snoqualmie Pass | Elevation |
|---|---|
| Thursday Afternoon | WSW 5 - 15 |
| Thursday Night - Friday Morning | W 0 - 10 |
| Friday Afternoon | ESE 10 - 20 |
| Friday Night | ESE 20 - 35 |
| Mt. Rainier | Elevation |
|---|---|
| Thursday Afternoon | --- - |
| Thursday Night - Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Mt. Hood | Elevation |
|---|---|
| Thursday Afternoon | W 15 - 25 |
| Thursday Night - Friday Morning | W 5 - 15 |
| Friday Afternoon | ESE 15 - 25 |
| Friday Night | SE 15 - 25 |
| Hurricane Ridge | Direction - Speed |
|---|---|
| Thursday Afternoon | W 0 - 10 |
| Thursday Night - Friday Morning | E 0 - 10 |
| Friday Afternoon | SE 5 - 15 |
| Friday Night | SE 10 - 20 |
| Mt. Baker | Direction - Speed |
|---|---|
| Thursday Afternoon | WSW 0 - 10 |
| Thursday Night - Friday Morning | VAR 0 - 10 |
| Friday Afternoon | E 5 - 15 |
| Friday Night | E 5 - 15 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | WSW 5 - 15 |
| Thursday Night - Friday Morning | W 0 - 10 |
| Friday Afternoon | ESE 10 - 20 |
| Friday Night | ESE 20 - 35 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Thursday Afternoon | --- - |
| Thursday Night - Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Thursday Afternoon | W 15 - 25 |
| Thursday Night - Friday Morning | W 5 - 15 |
| Friday Afternoon | ESE 15 - 25 |
| Friday Night | SE 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.
Free Winds at 9000' (mph)
| Mt. Baker | Washington Pass | Stevens to Snoqualmie Pass | Mt. Rainier | Mt. Hood | |
|---|---|---|---|---|---|
| Thursday Afternoon | W 10 - 20 | WNW 15 - 25 | W 15 - 30 | --- - | W 15 - 25 |
| Thursday Night - Friday Morning | N 5 - 15 | N 10 - 20 | N 5 - 15 | --- - | NW 0 - 10 |
| Friday Afternoon | S 10 - 20 | SE 5 - 15 | SE 20 - 30 | --- - | S 10 - 20 |
| Friday Night | S 10 - 20 | S 15 - 25 | SSE 20 - 35 | --- - | S 15 - 30 |
| Mt. Baker | Direction - Speed |
|---|---|
| Thursday Afternoon | W 10 - 20 |
| Thursday Night - Friday Morning | N 5 - 15 |
| Friday Afternoon | S 10 - 20 |
| Friday Night | S 10 - 20 |
| Washington Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | WNW 15 - 25 |
| Thursday Night - Friday Morning | N 10 - 20 |
| Friday Afternoon | SE 5 - 15 |
| Friday Night | S 15 - 25 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | W 15 - 30 |
| Thursday Night - Friday Morning | N 5 - 15 |
| Friday Afternoon | SE 20 - 30 |
| Friday Night | SSE 20 - 35 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Thursday Afternoon | --- - |
| Thursday Night - Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Thursday Afternoon | W 15 - 25 |
| Thursday Night - Friday Morning | NW 0 - 10 |
| Friday Afternoon | S 10 - 20 |
| Friday Night | S 15 - 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: 1:58 PM PDT Thursday, April 20, 2017
Extended Weather Synopsis for Monday night through Monday
The slow moving front should lift northeastward over the area on Saturday, with light rain and snow becoming showers in the afternoon. Locally moderate showers are most likely for the west slopes of the Cascades and Olympics, especially the Mt. Baker area Saturday night. The trailing longwave upper level trough should pass through the area on Sunday, with showers once again increasing in the afternoon. The moisture profile looks deeper on Sunday, so expect a cloudier and cooler day especially along the west slopes of the Cascades.
A rather impressive looking low pressure system for April is forecast to move into western Washington/southern British Columbia on Monday. The exact track will make a difference to how much rain and snow we receive, but a broad brush forecast of wetter and cooler than normal looks accurate for all areas on Monday.
Extended Weather
Olympics, Washington Cascades and Mt. Hood area
Periods of light rain and snow becoming light rain and snow showers, occasionally moderate along the west slopes of the Cascades and Olympics. More sunshine along the east slopes of the central-east and southeast Cascades.
Mostly cloudy with isolated rain and snow showers.
Cloudy with light rain and snow showers, occasionally moderate west slopes of the Cascades, Olympics and Mt. Hood.
Mostly cloudy with scattered light rain and snow showers.
Increasing light to moderate rain and snow.
Extended Snow/Freezing Levels
| Mt. Baker | Snoqualmie Pass | Mt. Hood | Easterly Flow * | ||
|---|---|---|---|---|---|
| Saturday | Snow Level | 5500' - 6500' | 5500' - 6500' | 6000' - 7000' | |
| Saturday Night - Sunday | Snow Level | 4500' - 5500' | 4500' - 5500' | 4500' - 5500' | |
| Sunday Night - Monday | Snow Level | 4000' - 5000' | 4000' - 5000' | 4000' - 5000' |
| Mt. Baker | Elevation |
|---|---|
| Saturday |
Snow Level 5500' - 6500' |
| Saturday Night - Sunday |
Snow Level 4500' - 5500' |
| Sunday Night - Monday |
Snow Level 4000' - 5000' |
| Snoqualmie Pass | Elevation |
|---|---|
| Saturday |
Snow Level 5500' - 6500' |
| Saturday Night - Sunday |
Snow Level 4500' - 5500' |
| Sunday Night - Monday |
Snow Level 4000' - 5000' |
| Mt. Hood | Elevation |
|---|---|
| Saturday |
Snow Level 6000' - 7000' |
| Saturday Night - Sunday |
Snow Level 4500' - 5500' |
| Sunday Night - Monday |
Snow Level 4000' - 5000' |
* 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 Apr 15, 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.
Spring Schedule: The NWAC issued daily mountain weather and avalanche forecasts through Saturday, April 15th. Mountain weather and avalanche forecasts will be issued during the spring transition April 20-22nd and April 27-29th. Weekend outlooks will be issued Thursdays, May 4th, 11th, 18th and 25th.