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 & Tuesday
Yesterday's ridge of high pressure is shifting inland over Idaho this morning as a Pacific frontal system approaches us. The frontal system should spread light rain and snow inland during the day...with the front reaching the Cascades in the late afternoon or early evening. Precipitation amounts have been shifted downward with this system. A strong temperature inversion exists near the Cascade passes with plenty of cold air over on the eastern side of state (Mazama is in the single digits, while many higher elevation NWAC sites are above freezing). With the easterly flow in the Cascade passes through late afternoon, a mix of snow and freezing rain could begin for Snoqualmie Pass before westerly flow resets the snow level to around 3500 ft later this evening.
Showers will continue through Friday morning with weak NW flow aloft. Light showers and/or light warm frontal precipitation from a system offshore and directed at the central British Columbia coast should continue dribs and drabs of precipitation for the west slopes of the Olympics and Cascades on Friday. A slight warming trend should take place Friday. The upper level ridge will flatten Friday night but the area should remain mostly dry as frontal system stays well north of the border.
Weather Forecast
Olympics, Washington Cascades near and west of the crest including Stevens, Snoqualmie, and White Passes
| Thursday |
Mostly cloudy with light rain and snow developing Olympics and North Cascades in the late morning/early afternoon. |
| Thursday Evening - Friday Morning |
Light to moderate rain and snow, heaviest west slopes. Short period of freezing rain possibly mixed with rain/snow for Cascades Passes at the onset of precipitation in the late afternoon/early evening. |
| Thursday Night - Friday |
Light rain and snow showers generally decreasing except light to moderate showers North Cascades. |
| Friday Night |
Mostly cloudy. |
Mt. Hood Area
| Thursday |
Mostly cloudy. |
| Thursday Evening - Friday Morning |
Light rain and snow developing in the evening. |
| Friday Afternoon - Friday Night |
Mostly cloudy. |
East slopes of the Washington Cascades
| Thursday |
Mostly cloudy. |
| Thursday Evening |
Light rain and snow developing in the evening. |
| Thursday Night - Friday Afternoon |
Light rain and snow showers generally decreasing on Friday. |
| Friday Night |
Mostly cloudy. |
Issued: 7:59 AM PST Thursday, December 12, 2013
Snow/Freezing Level (ft)
| Hurricane Ridge | Mt. Baker | Washington Pass | Leavenworth | Stevens Pass | Snoqualmie Pass | Mt. Rainier, Crystal & White Pass | Mt. Hood | ||
|---|---|---|---|---|---|---|---|---|---|
| Thursday Morning | Snow Level * | 3000' | ' | ' | ' | ' | 3000' | ' | 5000' |
| Thursday Afternoon | Snow Level * | 4000' | ' | ' | ' | ' | 3500' | ' | 3500' |
| Thursday Evening | Snow Level | 5000' | ' | ' | ' | ' | 3500' | ' | 3500' |
| Thursday Night - Friday Morning | Snow Level | 5000' | ' | ' | ' | ' | 4000' | ' | 4500' |
| Friday Afternoon - Friday Night | Snow Level | 5000' | ' | ' | ' | ' | 4500' | ' | 6500' |
| Hurricane Ridge | Elevation |
|---|---|
| Thursday Morning |
Snow Level 3000' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level 4000' (Easterly Flow *) |
| Thursday Evening |
Snow Level 5000' |
| Thursday Night - Friday Morning |
Snow Level 5000' |
| Friday Afternoon - Friday Night |
Snow Level 5000' |
| Mt. Baker | Elevation |
|---|---|
| Thursday Morning |
Snow Level ' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level ' (Easterly Flow *) |
| Thursday Evening |
Snow Level ' |
| Thursday Night - Friday Morning |
Snow Level ' |
| Friday Afternoon - Friday Night |
Snow Level ' |
| Washington Pass | Elevation |
|---|---|
| Thursday Morning |
Snow Level ' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level ' (Easterly Flow *) |
| Thursday Evening |
Snow Level ' |
| Thursday Night - Friday Morning |
Snow Level ' |
| Friday Afternoon - Friday Night |
Snow Level ' |
| Leavenworth | Elevation |
|---|---|
| Thursday Morning |
Snow Level ' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level ' (Easterly Flow *) |
| Thursday Evening |
Snow Level ' |
| Thursday Night - Friday Morning |
Snow Level ' |
| Friday Afternoon - Friday Night |
Snow Level ' |
| Stevens Pass | Elevation |
|---|---|
| Thursday Morning |
Snow Level ' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level ' (Easterly Flow *) |
| Thursday Evening |
Snow Level ' |
| Thursday Night - Friday Morning |
Snow Level ' |
| Friday Afternoon - Friday Night |
Snow Level ' |
| Snoqualmie Pass | Elevation |
|---|---|
| Thursday Morning |
Snow Level 3000' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level 3500' (Easterly Flow *) |
| Thursday Evening |
Snow Level 3500' |
| Thursday Night - Friday Morning |
Snow Level 4000' |
| Friday Afternoon - Friday Night |
Snow Level 4500' |
| Mt. Rainier & Crystal | Elevation |
|---|---|
| Thursday Morning |
Snow Level ' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level ' (Easterly Flow *) |
| Thursday Evening |
Snow Level ' |
| Thursday Night - Friday Morning |
Snow Level ' |
| Friday Afternoon - Friday Night |
Snow Level ' |
| Mt. Hood | Elevation |
|---|---|
| Thursday Morning |
Snow Level 5000' (Easterly Flow *) |
| Thursday Afternoon |
Snow Level 3500' (Easterly Flow *) |
| Thursday Evening |
Snow Level 3500' |
| Thursday Night - Friday Morning |
Snow Level 4500' |
| Friday Afternoon - Friday Night |
Snow Level 6500' |
* 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
| Tuesday | Tuesday | |
|---|---|---|
| Hurricane Ridge | LT 0.25 | LT 0.10 |
| Mt Baker Ski Area | 0 - 0.75 | LT 0.25 |
| Washington Pass | LT 0.25 | LT 0.10 |
| Stevens Pass | 0.25 - 0.50 | LT 0.25 |
| Snoqualmie Pass | 0 - 0.50 | LT 0.25 |
| Mission Ridge | LT 0.10 | LT 0.10 |
| Crystal Mt | LT 0.25 | LT 0.10 |
| Paradise | 0.50 - 0.75 | LT 0.25 |
| White Pass | LT 0.25 | LT 0.10 |
| Mt Hood Meadows | LT 0.25 | LT 0.10 |
| Timberline | 0.25 - 0.50 | 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: 7:59 AM PST Thursday, December 12, 2013
Free Winds at 5000' (mph)
| Hurricane Ridge | Mt. Baker | Stevens to Snoqualmie Pass | Mt. Rainier | Mt. Hood | |
|---|---|---|---|---|---|
| Thursday | SW 20 - 30 | --- - | SW 20 - 30 | --- - | SW 15 - 30 |
| Thursday Night | W 10 - 20 | --- - | W 10 - 20 | --- - | WSW 15 - 25 |
| Friday - Friday Night | W 5 - 15 | --- - | WSW 5 - 15 | --- - | WSW 5 - 15 |
| Hurricane Ridge | Elevation |
|---|---|
| Thursday | SW 20 - 30 |
| Thursday Night | W 10 - 20 |
| Friday - Friday Night | W 5 - 15 |
| Mt. Baker | Elevation |
|---|---|
| Thursday | --- - |
| Thursday Night | --- - |
| Friday - Friday Night | --- - |
| Stevens and Snoqualmie Pass | Elevation |
|---|---|
| Thursday | SW 20 - 30 |
| Thursday Night | W 10 - 20 |
| Friday - Friday Night | WSW 5 - 15 |
| Mt. Rainier | Elevation |
|---|---|
| Thursday | --- - |
| Thursday Night | --- - |
| Friday - Friday Night | --- - |
| Mt. Hood | Elevation |
|---|---|
| Thursday | SW 15 - 30 |
| Thursday Night | WSW 15 - 25 |
| Friday - Friday Night | WSW 5 - 15 |
| Hurricane Ridge | Direction - Speed |
|---|---|
| Thursday | SW 20 - 30 |
| Thursday Night | W 10 - 20 |
| Friday - Friday Night | W 5 - 15 |
| Mt. Baker | Direction - Speed |
|---|---|
| Thursday | --- - |
| Thursday Night | --- - |
| Friday - Friday Night | --- - |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Thursday | SW 20 - 30 |
| Thursday Night | W 10 - 20 |
| Friday - Friday Night | WSW 5 - 15 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Thursday | --- - |
| Thursday Night | --- - |
| Friday - Friday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Thursday | SW 15 - 30 |
| Thursday Night | WSW 15 - 25 |
| Friday - Friday Night | WSW 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 - Thursday | --- - | --- - | SW 30 - 40 | --- - | SW 25 - 35 |
| Thursday Night - Thursday | --- - | --- - | W 15 - 25 | --- - | W 15 - 25 |
| Friday - Friday Night | --- - | --- - | NW 25 - 35 | --- - | NW 25 - 35 |
| Mt. Baker | Direction - Speed |
|---|---|
| Thursday - Thursday | --- - |
| Thursday Night - Thursday | --- - |
| Friday - Friday Night | --- - |
| Washington Pass | Direction - Speed |
|---|---|
| Thursday - Thursday | --- - |
| Thursday Night - Thursday | --- - |
| Friday - Friday Night | --- - |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Thursday - Thursday | SW 30 - 40 |
| Thursday Night - Thursday | W 15 - 25 |
| Friday - Friday Night | NW 25 - 35 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Thursday - Thursday | --- - |
| Thursday Night - Thursday | --- - |
| Friday - Friday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Thursday - Thursday | SW 25 - 35 |
| Thursday Night - Thursday | W 15 - 25 |
| Friday - Friday Night | NW 25 - 35 |
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: 7:59 AM PST Thursday, December 12, 2013
Extended Weather Synopsis for Tuesday night through Tuesday
The weak frontal system aimed at central British Columbia should move south and drape over the N Cascades and Olympics on Saturday, and finally shift south Saturday night. Rain/snow amounts looks generally light with this system and will be accompanied by rising snow levels Saturday night. Of interest with this system should be the strong westerly winds experienced in the alpine as the jet stream sags south and becomes aimed at Washington.
Showers along with some cooling should take place Sunday day through early Monday as an upper ridge of high pressure re-establishes itself along the west coast. Showers should decrease later Monday.
Extended Weather
Washington Cascades
Mostly cloudy with periods of light rain or snow North Cascades. Strong alpine winds.
Mostly cloudy with periods of light rain or snow, except occasionally moderate North Cascades. Strong alpine winds. Warming overnight.
Light rain and snow showers diminishing on Monday. Cooling Sunday night and Monday.
Mt. Hood Area
Partly to mostly cloudy.
Mostly cloudy with periods of light rain or snow. Strong alpine winds. Warming overnight.
Light rain and snow showers diminishing early Monday.
Partly cloudy.
Extended Snow/Freezing Levels
| Mt. Baker | Snoqualmie Pass | Mt. Hood | Easterly Flow * | ||
|---|---|---|---|---|---|
| Saturday | Snow Level | ' - ' | 4500' - 5500' | 4500' - 5500' | |
| Saturday Night - Sunday Morning | Snow Level | ' - ' | 5000' - 7000' | 6000' - 8000' | |
| Sunday Afternoon - Monday | Snow Level | ' - ' | 3000' - 5000' | 4000' - 6000' |
| Mt. Baker | Elevation |
|---|---|
| Saturday |
Snow Level ' - ' |
| Saturday Night - Sunday Morning |
Snow Level ' - ' |
| Sunday Afternoon - Monday |
Snow Level ' - ' |
| Snoqualmie Pass | Elevation |
|---|---|
| Saturday |
Snow Level 4500' - 5500' |
| Saturday Night - Sunday Morning |
Snow Level 5000' - 7000' |
| Sunday Afternoon - Monday |
Snow Level 3000' - 5000' |
| Mt. Hood | Elevation |
|---|---|
| Saturday |
Snow Level 4500' - 5500' |
| Saturday Night - Sunday Morning |
Snow Level 6000' - 8000' |
| Sunday Afternoon - Monday |
Snow Level 4000' - 6000' |
* 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
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.