Jump to: Weather Forecast I Snow/Freezing Level I Precipitation I Free Winds 5k I Free Winds 9k I Extended Weather
Weather Synopsis for Wednesday & Monday
A shortwave trough in moderate westerly flow aloft will pass through the Pacific Northwest today. Snowfall totals look light with this system as it splits with the southern energy forming a cut-off low over California and the northern energy passing through to the upper Plains.
As the system dives south today, northerly flow aloft will develop by Wednesday evening, and surface high pressure will slide south into British Columbia, helping to deliver much colder air into Washington and Oregon. There could be a brief period of convergence and enhanced snow showers from Snoqualmie Pass and south toward Mt. Rainier this evening before drying and clearing. There may be some additional weak upslope clouds and light snow showers along the northern Olympics this evening with the northerly surface gradients.
After a sunny and cold start to Thursday, increasing high clouds will stream in from the northwest in the afternoon. Cloud decks should slowly lower Thursday night from north to south ahead of incoming frontal system. Light snow may develop overnight for the Olympics and North Cascades.
Weather Forecast
Olympics, Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
| Wednesday - Wednesday Evening |
Light rain and snow showers, increasing slightly in the afternoon. Lowering snow levels through the day. Partial clearing in the evening except for potential showers near convergence zone Snoqualmie Pass and south and along north slopes of the Olympics. |
| Wednesday Night - Thursday Morning |
Mostly clear. |
| Thursday Afternoon - Thursday Night |
Increasing clouds in the afternoon and lowering overnight. Light snow possible Olympics and North Cascades overnight. |
East slopes of the Washington Cascades
| Wednesday - Wednesday Evening |
Light rain and snow showers. Lowering snow levels through the day. Clearing in the evening. |
| Wednesday Night - Thursday Morning |
Mostly clear. |
| Thursday Afternoon - Thursday Night |
Increasing clouds in the afternoon and lowering overnight. Light snow possible Northeast Cascades overnight. |
Mt. Hood Area
| Wednesday - Wednesday Evening |
Light rain and snow showers beginning in the afternoon. Lowering snow levels through the day. |
| Wednesday Night - Thursday Afternoon |
Mostly clear. |
| Thursday Evening - Thursday Night |
Increasing clouds in the evening and lowering overnight. |
Issued: 7:04 AM PST Wednesday, December 18, 2013
Snow/Freezing Level (ft)
| Hurricane Ridge | Mt. Baker | Washington Pass | Leavenworth | Stevens Pass | Snoqualmie Pass | Mt. Rainier, Crystal & White Pass | Mt. Hood | ||
|---|---|---|---|---|---|---|---|---|---|
| Wednesday Morning | Snow Level | 2500' | ' | ' | ' | ' | 3500' | ' | 5000' |
| Wednesday Afternoon - Wednesday Evening | Snow Level | 1500' | ' | ' | ' | ' | 1500' | ' | 2000' |
| Wednesday Night | Freezing Level | 500' | ' | ' | ' | ' | 500' | ' | 1000' |
| Thursday | Freezing Level | 2000' | ' | ' | ' | ' | 1500' | ' | 2500' |
| Thursday Night | Snow Level | 2500' | ' | ' | ' | ' | 500' | ' | 1500' |
| Hurricane Ridge | Elevation |
|---|---|
| Wednesday Morning |
Snow Level 2500' |
| Wednesday Afternoon - Wednesday Evening |
Snow Level 1500' |
| Wednesday Night |
Freezing Level 500' |
| Thursday |
Freezing Level 2000' |
| Thursday Night |
Snow Level 2500' |
| Mt. Baker | Elevation |
|---|---|
| Wednesday Morning |
Snow Level ' |
| Wednesday Afternoon - Wednesday Evening |
Snow Level ' |
| Wednesday Night |
Freezing Level ' |
| Thursday |
Freezing Level ' |
| Thursday Night |
Snow Level ' |
| Washington Pass | Elevation |
|---|---|
| Wednesday Morning |
Snow Level ' |
| Wednesday Afternoon - Wednesday Evening |
Snow Level ' |
| Wednesday Night |
Freezing Level ' |
| Thursday |
Freezing Level ' |
| Thursday Night |
Snow Level ' |
| Leavenworth | Elevation |
|---|---|
| Wednesday Morning |
Snow Level ' |
| Wednesday Afternoon - Wednesday Evening |
Snow Level ' |
| Wednesday Night |
Freezing Level ' |
| Thursday |
Freezing Level ' |
| Thursday Night |
Snow Level ' |
| Stevens Pass | Elevation |
|---|---|
| Wednesday Morning |
Snow Level ' |
| Wednesday Afternoon - Wednesday Evening |
Snow Level ' |
| Wednesday Night |
Freezing Level ' |
| Thursday |
Freezing Level ' |
| Thursday Night |
Snow Level ' |
| Snoqualmie Pass | Elevation |
|---|---|
| Wednesday Morning |
Snow Level 3500' |
| Wednesday Afternoon - Wednesday Evening |
Snow Level 1500' |
| Wednesday Night |
Freezing Level 500' |
| Thursday |
Freezing Level 1500' |
| Thursday Night |
Snow Level 500' |
| Mt. Rainier & Crystal | Elevation |
|---|---|
| Wednesday Morning |
Snow Level ' |
| Wednesday Afternoon - Wednesday Evening |
Snow Level ' |
| Wednesday Night |
Freezing Level ' |
| Thursday |
Freezing Level ' |
| Thursday Night |
Snow Level ' |
| Mt. Hood | Elevation |
|---|---|
| Wednesday Morning |
Snow Level 5000' |
| Wednesday Afternoon - Wednesday Evening |
Snow Level 2000' |
| Wednesday Night |
Freezing Level 1000' |
| Thursday |
Freezing Level 2500' |
| Thursday Night |
Snow 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
| Monday | Monday | |
|---|---|---|
| Hurricane Ridge | LT 0.10 | LT 0.25 |
| Mt Baker Ski Area | LT 0.25 | LT 0.25 |
| Washington Pass | LT 0.10 | LT 0.10 |
| Stevens Pass | LT 0.25 | LT 0.10 |
| Snoqualmie Pass | LT 0.25 | LT 0.10 |
| Mission Ridge | LT 0.10 | LT 0.10 |
| Crystal Mt | LT 0.25 | LT 0.10 |
| Paradise | LT 0.25 | LT 0.10 |
| White Pass | LT 0.10 | LT 0.10 |
| Mt Hood Meadows | LT 0.10 | 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: 7:04 AM PST Wednesday, December 18, 2013
Free Winds at 5000' (mph)
| Hurricane Ridge | Mt. Baker | Stevens to Snoqualmie Pass | Mt. Rainier | Mt. Hood | |
|---|---|---|---|---|---|
| Wednesday Morning | W 15 - 25 | --- - | W 10 - 20 | --- - | NW 10 - 20 |
| Wednesday Afternoon - Thursday Morning | NE 10 - 20 | --- - | N 5 - 15 | --- - | N 10 - 20 |
| Thursday Afternoon - Thursday Night | W 5 - 15 | --- - | W 5 - 15 | --- - | WNW 10 - 20 |
| Hurricane Ridge | Elevation |
|---|---|
| Wednesday Morning | W 15 - 25 |
| Wednesday Afternoon - Thursday Morning | NE 10 - 20 |
| Thursday Afternoon - Thursday Night | W 5 - 15 |
| Mt. Baker | Elevation |
|---|---|
| Wednesday Morning | --- - |
| Wednesday Afternoon - Thursday Morning | --- - |
| Thursday Afternoon - Thursday Night | --- - |
| Stevens and Snoqualmie Pass | Elevation |
|---|---|
| Wednesday Morning | W 10 - 20 |
| Wednesday Afternoon - Thursday Morning | N 5 - 15 |
| Thursday Afternoon - Thursday Night | W 5 - 15 |
| Mt. Rainier | Elevation |
|---|---|
| Wednesday Morning | --- - |
| Wednesday Afternoon - Thursday Morning | --- - |
| Thursday Afternoon - Thursday Night | --- - |
| Mt. Hood | Elevation |
|---|---|
| Wednesday Morning | NW 10 - 20 |
| Wednesday Afternoon - Thursday Morning | N 10 - 20 |
| Thursday Afternoon - Thursday Night | WNW 10 - 20 |
| Hurricane Ridge | Direction - Speed |
|---|---|
| Wednesday Morning | W 15 - 25 |
| Wednesday Afternoon - Thursday Morning | NE 10 - 20 |
| Thursday Afternoon - Thursday Night | W 5 - 15 |
| Mt. Baker | Direction - Speed |
|---|---|
| Wednesday Morning | --- - |
| Wednesday Afternoon - Thursday Morning | --- - |
| Thursday Afternoon - Thursday Night | --- - |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Wednesday Morning | W 10 - 20 |
| Wednesday Afternoon - Thursday Morning | N 5 - 15 |
| Thursday Afternoon - Thursday Night | W 5 - 15 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Wednesday Morning | --- - |
| Wednesday Afternoon - Thursday Morning | --- - |
| Thursday Afternoon - Thursday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Wednesday Morning | NW 10 - 20 |
| Wednesday Afternoon - Thursday Morning | N 10 - 20 |
| Thursday Afternoon - Thursday 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 | |
|---|---|---|---|---|---|
| Wednesday Morning | --- - | --- - | WNW 30 - 40 | --- - | WNW 25 - 40 |
| Wednesday Afternoon - Thursday Morning | --- - | --- - | N 10 - 20 | --- - | NE 15 - 30 |
| Thursday Afternoon - Thursday Night | --- - | --- - | NW 30 - 45 | --- - | NW 25 - 40 |
| Mt. Baker | Direction - Speed |
|---|---|
| Wednesday Morning | --- - |
| Wednesday Afternoon - Thursday Morning | --- - |
| Thursday Afternoon - Thursday Night | --- - |
| Washington Pass | Direction - Speed |
|---|---|
| Wednesday Morning | --- - |
| Wednesday Afternoon - Thursday Morning | --- - |
| Thursday Afternoon - Thursday Night | --- - |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Wednesday Morning | WNW 30 - 40 |
| Wednesday Afternoon - Thursday Morning | N 10 - 20 |
| Thursday Afternoon - Thursday Night | NW 30 - 45 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Wednesday Morning | --- - |
| Wednesday Afternoon - Thursday Morning | --- - |
| Thursday Afternoon - Thursday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Wednesday Morning | WNW 25 - 40 |
| Wednesday Afternoon - Thursday Morning | NE 15 - 30 |
| Thursday Afternoon - Thursday Night | NW 25 - 40 |
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: 7:04 AM PST Wednesday, December 18, 2013
Extended Weather Synopsis for Monday night through Monday
A significant weather system will impact the area on Friday. Snow levels should start out very low Friday morning and gradually rise during the day. Warm frontal precipitation riding up and over strong upper level ridging offshore should increase in intensity during the afternoon and evening hours. Most weather models have moderate to occasionally heavy rain and snow by Friday afternoon for the west slopes of the Washington Cascades.
Lack of substantial easterly flow through the passes and a rapid warming trend should make for a messy transition from rain to snow at lower and mid-elevations and inverted snowfall Friday through Friday night. Northwest winds are forecast to be quite strong in the alpine during this period.
Periods of light rain and snow from weaker systems will brush the area Saturday and Sunday as the strong high pressure offshore keeps us mild and drippy.
Extended Weather
Olympics, Washington Cascades and Mt. Hood area
Light snow becoming moderate North Cascades and light snow spreading south.
Rain and snow, heavy at times west slopes of the Cascades. Warming trend continues overnight. Strong NW alpine winds.
Mostly cloudy with periods of light rain and snow. Generally mild.
Light to moderate rain and snow showers tapering down in the afternoon.
Extended Snow/Freezing Levels
| Mt. Baker | Snoqualmie Pass | Mt. Hood | Easterly Flow * | ||
|---|---|---|---|---|---|
| Friday Morning | Snow Level | ' - ' | 2000' - 3000' | 3500' - 4500' | |
| Friday Afternoon | Snow Level | ' - ' | 3500' - 5000' | 6500' - 7500' | |
| Friday Night | Snow Level | ' - ' | 5000' - 6500' | 6500' - 7500' | |
| Saturday - Sunday | Snow Level | ' - ' | 4500' - 6500' | 5500' - 7500' |
| Mt. Baker | Elevation |
|---|---|
| Friday Morning |
Snow Level ' - ' |
| Friday Afternoon |
Snow Level ' - ' |
| Friday Night |
Snow Level ' - ' |
| Saturday - Sunday |
Snow Level ' - ' |
| Snoqualmie Pass | Elevation |
|---|---|
| Friday Morning |
Snow Level 2000' - 3000' |
| Friday Afternoon |
Snow Level 3500' - 5000' |
| Friday Night |
Snow Level 5000' - 6500' |
| Saturday - Sunday |
Snow Level 4500' - 6500' |
| Mt. Hood | Elevation |
|---|---|
| Friday Morning |
Snow Level 3500' - 4500' |
| Friday Afternoon |
Snow Level 6500' - 7500' |
| Friday Night |
Snow Level 6500' - 7500' |
| Saturday - Sunday |
Snow Level 5500' - 7500' |
* 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 17, 2013
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.