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 & Friday
A moist NW flow will prevail on Thursday as the Pacific Northwest continues to sit between a broad ridge of high pressure (centered off the California coast around 145 W) and a large-scale trough over interior Canada. The moist westerly flow will continue to bank clouds against the west slopes Cascades, bringing isolated snow showers to the west slopes of the Cascades today, with scattered snow showers and minor accumulation most likely at Mt. Hood.
A shortwave trough is sliding down the British Columbia coastline, already spreading high clouds ahead of it along with increasing rain and snow starting in the evening hours on Thursday. Snow levels will gradually rise as the shortwave trough approaches and with the jetstream shifting north slightly into British Columbia, allowing slightly warmer air to move into the region. The shortwave will be associated with a weak surface cold frontal feature which should pass the Cascades on Friday afternoon, bring in slightly cooler air Friday night. Crest-level winds will also increase into the moderate range by Friday morning and may become strong at times in the central and south Cascades. Late Friday afternoon it is likely that Snoqualmie pass will see a changeover to rain or very wet snow right at pass level for some hours before changing back to snow, while Stevens Pass is unlikely to see rain at pass level.
Friday night post-frontal rain and snow showers will gradually decrease, but be will be replaced with incoming moisture ahead of a stronger trough and storm system sliding southeastward along the British Columbia coastline, slated to arrive on Saturday.
Weather Forecast
Olympics
| Thursday | Increasing high clouds with some scattered low clouds. |
| Thursday Night | Clouds lowering and thickening with increasing light snow after midnight. |
| Friday | Decreasing light snow ending during the afternoon hours with some slight clearing possible by late afternoon. |
| Friday Night | Increasing clouds with light rain and snow arriving after midnight. |
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
| Thursday | Mostly cloudy with a mix of low clouds and increasing high clouds. Isolated snow showers. |
| Thursday Night | Increasing light snow becoming moderate after midnight. Westerly winds increasing to moderate. |
| Friday | Moderate rain and snow becoming moderate rain and snow showers by mid-afternoon with shower activity most prevalent from Snoqualmie Pass north to the Skagit Valley. Moderate to occasionally strong crest-level winds. |
| Friday Night | Increasing clouds with light rain and snow arriving after midnight. Increasing crest-level winds. |
East Slopes of the Washington Cascades
| Thursday | Increasing high clouds. |
| Thursday Night | Increasing light snow. Westerly winds becoming moderate. |
| Friday | Light rain and snow becoming showery by mid-afternoon with shower activity most prevalent central part. Moderate to occasionally strong crest-level winds. |
| Friday Night | Increasing clouds with light rain and snow arriving after midnight. Increasing crest-level winds. |
Mt. Hood
| Thursday | Cloudy with scattered snow showers. |
| Thursday Night | Light snow becoming moderate after midnight. |
| Friday | Moderate rain and snow with rising snow levels. Moderate crest-level winds. |
| Friday Night | Light to moderate rain and snow showers continue and become light to moderate rain and snow as flow shifts from westerly to W-SW. |
Issued: 2:44 PM PST Thursday, February 15, 2018
Snow/Freezing Level (ft)
| Hurricane Ridge | Mt. Baker | Washington Pass | Leavenworth | Stevens Pass | Snoqualmie Pass | Mt. Rainier, Crystal & White Pass | Mt. Hood | ||
|---|---|---|---|---|---|---|---|---|---|
| Thursday Afternoon | Snow Level | 1500' | 1500' | 1500' | ' | ' | 2000' | ' | 2500' |
| Thursday Night | Snow Level | 2000' | 1500' | 1500' | ' | ' | 2000' | ' | 2000' |
| Friday Morning | Snow Level | 3500' | 2000' | 1500' | ' | ' | 2500' | ' | 3000' |
| Friday Afternoon | Snow Level | 3000' | 2500' | 2500' | ' | ' | 3500' | ' | 4000' |
| Friday Night | Snow Level | 3000' | 2500' | 2500' | ' | ' | 3000' | ' | 4500' |
| Hurricane Ridge | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level 1500' |
| Thursday Night |
Snow Level 2000' |
| Friday Morning |
Snow Level 3500' |
| Friday Afternoon |
Snow Level 3000' |
| Friday Night |
Snow Level 3000' |
| Mt. Baker | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level 1500' |
| Thursday Night |
Snow Level 1500' |
| Friday Morning |
Snow Level 2000' |
| Friday Afternoon |
Snow Level 2500' |
| Friday Night |
Snow Level 2500' |
| Washington Pass | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level 1500' |
| Thursday Night |
Snow Level 1500' |
| Friday Morning |
Snow Level 1500' |
| Friday Afternoon |
Snow Level 2500' |
| Friday Night |
Snow Level 2500' |
| Leavenworth | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level ' |
| Thursday Night |
Snow Level ' |
| Friday Morning |
Snow Level ' |
| Friday Afternoon |
Snow Level ' |
| Friday Night |
Snow Level ' |
| Stevens Pass | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level ' |
| Thursday Night |
Snow Level ' |
| Friday Morning |
Snow Level ' |
| Friday Afternoon |
Snow Level ' |
| Friday Night |
Snow Level ' |
| Snoqualmie Pass | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level 2000' |
| Thursday Night |
Snow Level 2000' |
| Friday Morning |
Snow Level 2500' |
| Friday Afternoon |
Snow Level 3500' |
| Friday Night |
Snow Level 3000' |
| Mt. Rainier & Crystal | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level ' |
| Thursday Night |
Snow Level ' |
| Friday Morning |
Snow Level ' |
| Friday Afternoon |
Snow Level ' |
| Friday Night |
Snow Level ' |
| Mt. Hood | Elevation |
|---|---|
| Thursday Afternoon |
Snow Level 2500' |
| Thursday Night |
Snow Level 2000' |
| Friday Morning |
Snow Level 3000' |
| Friday Afternoon |
Snow Level 4000' |
| Friday Night |
Snow Level 4500' |
* 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
| Friday | Friday | |
|---|---|---|
| Hurricane Ridge | LT 0.10 | LT 0.25 |
| Mt Baker Ski Area | LT 0.25 | 0 - 0.50 |
| Washington Pass | LT 0.25 | LT 0.25 |
| Stevens Pass | 0.25 - 0.50 | 0 - 1.00 |
| Snoqualmie Pass | 0.25 - 0.50 | 1.00 - 1.25 |
| Mission Ridge | LT 0.10 | LT 0.10 |
| Crystal Mt | LT 0.10 | LT 0.25 |
| Paradise | 0.25 - 0.50 | 1.00 - 1.25 |
| White Pass | LT 0.25 | 0 - 0.75 |
| Mt Hood Meadows | 0.25 - 0.50 | 0 - 1.00 |
| Timberline | 0.25 - 0.50 | 1.00 - 1.25 |
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: 2:44 PM PST Thursday, February 15, 2018
Free Winds at 5000' (mph)
| Hurricane Ridge | Mt. Baker | Stevens to Snoqualmie Pass | Mt. Rainier | Mt. Hood | |
|---|---|---|---|---|---|
| Thursday Afternoon | WSW 10 - 20 | SSW 10 - 20 | W 15 - 25 | --- - | W 20 - 30 |
| Thursday Night | WSW 20 - 30 | SW 15 - 25 | W 20 - 30 | --- - | W 25 - 35 |
| Friday Morning | WSW 20 - 30 | WSW 20 - 30 | WSW 25 - 35 | --- - | WSW 30 - 40 |
| Friday Afternoon | W 15 - 25 | W 15 - 25 | W 30 - 40 | --- - | WSW 30 - 40 |
| Friday Night | SW 20 - 30 | SW 15 - 25 | WSW 25 - 35 | --- - | WSW 30 - 45 |
| Hurricane Ridge | Elevation |
|---|---|
| Thursday Afternoon | WSW 10 - 20 |
| Thursday Night | WSW 20 - 30 |
| Friday Morning | WSW 20 - 30 |
| Friday Afternoon | W 15 - 25 |
| Friday Night | SW 20 - 30 |
| Mt. Baker | Elevation |
|---|---|
| Thursday Afternoon | SSW 10 - 20 |
| Thursday Night | SW 15 - 25 |
| Friday Morning | WSW 20 - 30 |
| Friday Afternoon | W 15 - 25 |
| Friday Night | SW 15 - 25 |
| Stevens and Snoqualmie Pass | Elevation |
|---|---|
| Thursday Afternoon | W 15 - 25 |
| Thursday Night | W 20 - 30 |
| Friday Morning | WSW 25 - 35 |
| Friday Afternoon | W 30 - 40 |
| Friday Night | WSW 25 - 35 |
| Mt. Rainier | Elevation |
|---|---|
| Thursday Afternoon | --- - |
| Thursday Night | --- - |
| Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Mt. Hood | Elevation |
|---|---|
| Thursday Afternoon | W 20 - 30 |
| Thursday Night | W 25 - 35 |
| Friday Morning | WSW 30 - 40 |
| Friday Afternoon | WSW 30 - 40 |
| Friday Night | WSW 30 - 45 |
| Hurricane Ridge | Direction - Speed |
|---|---|
| Thursday Afternoon | WSW 10 - 20 |
| Thursday Night | WSW 20 - 30 |
| Friday Morning | WSW 20 - 30 |
| Friday Afternoon | W 15 - 25 |
| Friday Night | SW 20 - 30 |
| Mt. Baker | Direction - Speed |
|---|---|
| Thursday Afternoon | SSW 10 - 20 |
| Thursday Night | SW 15 - 25 |
| Friday Morning | WSW 20 - 30 |
| Friday Afternoon | W 15 - 25 |
| Friday Night | SW 15 - 25 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | W 15 - 25 |
| Thursday Night | W 20 - 30 |
| Friday Morning | WSW 25 - 35 |
| Friday Afternoon | W 30 - 40 |
| Friday Night | WSW 25 - 35 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Thursday Afternoon | --- - |
| Thursday Night | --- - |
| Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Thursday Afternoon | W 20 - 30 |
| Thursday Night | W 25 - 35 |
| Friday Morning | WSW 30 - 40 |
| Friday Afternoon | WSW 30 - 40 |
| Friday Night | WSW 30 - 45 |
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 | WSW 15 - 25 | WSW 15 - 25 | WSW 25 - 35 | --- - | W 25 - 35 |
| Thursday Night | WSW 25 - 35 | WSW 35 - 50 | W 40 - 60 | --- - | WNW 40 - 60 |
| Friday Morning | WSW 40 - 60 | WSW 45 - 65 | W 45 - 65 | --- - | WNW 45 - 65 |
| Friday Afternoon | W 20 - 30 | W 30 - 40 | W 50 - 70 | --- - | W 40 - 60 |
| Friday Night | WSW 25 - 35 | WSW 30 - 40 | WSW 45 - 65 | --- - | W 40 - 60 |
| Mt. Baker | Direction - Speed |
|---|---|
| Thursday Afternoon | WSW 15 - 25 |
| Thursday Night | WSW 25 - 35 |
| Friday Morning | WSW 40 - 60 |
| Friday Afternoon | W 20 - 30 |
| Friday Night | WSW 25 - 35 |
| Washington Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | WSW 15 - 25 |
| Thursday Night | WSW 35 - 50 |
| Friday Morning | WSW 45 - 65 |
| Friday Afternoon | W 30 - 40 |
| Friday Night | WSW 30 - 40 |
| Stevens and Snoqualmie Pass | Direction - Speed |
|---|---|
| Thursday Afternoon | WSW 25 - 35 |
| Thursday Night | W 40 - 60 |
| Friday Morning | W 45 - 65 |
| Friday Afternoon | W 50 - 70 |
| Friday Night | WSW 45 - 65 |
| Mt. Rainier | Direction - Speed |
|---|---|
| Thursday Afternoon | --- - |
| Thursday Night | --- - |
| Friday Morning | --- - |
| Friday Afternoon | --- - |
| Friday Night | --- - |
| Mt. Hood | Direction - Speed |
|---|---|
| Thursday Afternoon | W 25 - 35 |
| Thursday Night | WNW 40 - 60 |
| Friday Morning | WNW 45 - 65 |
| Friday Afternoon | W 40 - 60 |
| Friday Night | W 40 - 60 |
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: 2:44 PM PST Thursday, February 15, 2018
Extended Weather Synopsis for Friday night through Friday
On Saturday, a potent and well-developed storm system will follow its predecessor along the coast of British Columbia, with a shortwave trough and associated low pressure center crossing Vancouver Island Saturday morning and bringing a surface cold front from NW to SE across the Washington Cascades and Mt. Hood from 10 AM to 2PM. Heavy snow (and low elevation rain) and strong winds will increase ahead of the front on Saturday and temperatures will increase by a few degrees (perhaps causing snow to once again mix with rain at Snoqualmie Pass) before the cold front lowers snow levels rapidly on Saturday afternoon. The post-frontal westerly flow will continue continue to bring moderate to heavy snow to the mountains Saturday night along with decreasing winds and further dropping temperatures.
On Sunday, a cold upper trough will settle into the Pacific Northwest with a modified arctic front passing from north to south during the day, bringing northerly flow (and a component of offshore flow) and a chance for light accumulations of lowland snow. The modified arctic air mass will settle into the Pacific Northwest, bringing clearing skies and a very cold night on Sunday night, likely the coldest of the season.
The cold air mass will remain in place on Monday and fair weather is expected with northerly flow aloft.
Extended Weather
Olympics, Washington Cascades and Mt. Hood Area
Extended Snow/Freezing Levels
| Mt. Baker | Snoqualmie Pass | Mt. Hood | Easterly Flow * | ||
|---|---|---|---|---|---|
| Saturday | Snow Level | 1500' - 3500' | 1500' - 3500' | 3500' - 4500' | |
| Saturday Night | Snow Level | 0' - 2000' | 0' - 2000' | 1' - 3000' | |
| Sunday | Snow Level | 0' - 1000' | 0' - 1000' | 0' - 1000' | |
| Sunday Night | Snow Level | 0' - 1000' | 0' - 1000' | 0' - 1000' | * |
| Monday | Snow Level | 0' - 1000' | 0' - 1000' | 0' - 1000' |
| Mt. Baker | Elevation |
|---|---|
| Saturday |
Snow Level 1500' - 3500' |
| Saturday Night |
Snow Level 0' - 2000' |
| Sunday |
Snow Level 0' - 1000' |
| Sunday Night |
Snow Level 0' - 1000' (Easterly Flow *) |
| Monday |
Snow Level 0' - 1000' |
| Snoqualmie Pass | Elevation |
|---|---|
| Saturday |
Snow Level 1500' - 3500' |
| Saturday Night |
Snow Level 0' - 2000' |
| Sunday |
Snow Level 0' - 1000' |
| Sunday Night |
Snow Level 0' - 1000' (Easterly Flow *) |
| Monday |
Snow Level 0' - 1000' |
| Mt. Hood | Elevation |
|---|---|
| Saturday |
Snow Level 3500' - 4500' |
| Saturday Night |
Snow Level 1' - 3000' |
| Sunday |
Snow Level 0' - 1000' |
| Sunday Night |
Snow Level 0' - 1000' (Easterly Flow *) |
| Monday |
Snow Level 0' - 1000' |
* 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 Feb 15, 2018
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