Issued: 2:07 PM PST Monday, February 20, 2023
by Dennis D'Amico

Jump to: Weather Forecast I Precipitation I Snow Level I 5000' Temps I Ridgeline Winds I Extended Weather

Weather Synopsis

WNW flow continues to deliver light to occasionally moderate rain and snow and strong West winds to our mountains today, with the higher precipitation rates favoring areas near and west of the Cascade crest, particularly north of I-90. This pattern has seen little change since Sunday, but it will finally start to evolve late this afternoon and Monday night as a cold front sweeps down from the NW. 

Precipitation rates will begin to increase later this afternoon, becoming heavy in many areas through the frontal passage this evening. Snow levels, which have bumped around 3500-5500' across the region, will stay steady or increase slightly through this time period as well. Following the frontal passage, we can expect significant post-frontal showers in westerly flow as snow levels drop to around 2000' by sunrise Tuesday morning. Westerly ridgeline winds were already strong, and should become extreme overnight for a wide swath of the region. This is not an event to be caught out in the alpine or an exposed location tonight. There may be some convergence banding with the post-frontal snow showers, but the prevalence of showers up and down the Cascades with significant spillover due to the strong W winds along the east slope of the Cascades means everyone will see accumulating snow.  

An unseasonably cold upper trough will dig over the area on Tuesday, keeping convective snow showers at low snow levels going throughout the day.  Westerly winds should finally begin to back off in the afternoon, although they will linger longer down near Mt Hood. 

The pattern will change once again Tuesday night. Very cold air from the interior will come out the Fraser Valley and through the Cascades Passes with cold easterly flow.  We can expect light snow showers, with some light upslope enhancement along the east slopes of the Cascades and the north slopes of the Olympics in this pattern. 

Weather Forecast

Olympics
West North
West Central
West South
Stevens Pass
Snoqualmie Pass
East North
East Central
East South
Mt. Hood
Use dropdown to select your zone
Monday Night Light to occasionally moderate rain and snow becoming light to moderate rain and snow showers late evening. Strong to extreme ridgeline winds.
Tuesday Light to moderate snow showers. Strong ridgeline winds in the morning, decreasing to moderate in the afternoon.
Monday Night Moderate to heavy rain and snow becoming showers after midnight. Strong ridgeline winds.
Tuesday Light to moderate snow showers in the morning, becoming more scattered showers in the afternoon. Moderate ridgeline winds in the morning, decreasing in the afternoon.
Monday Night Moderate to heavy rain and snow becoming showers after midnight. Strong to extreme ridgeline winds.
Tuesday Light to moderate snow showers in the morning, becoming more scattered showers in the afternoon. Strong ridgeline winds in the morning, decreasing to moderate in the afternoon.
Monday Night Moderate to heavy rain and snow becoming showers after midnight. Strong to extreme ridgeline winds.
Tuesday Light to moderate snow showers. Strong to extreme ridgeline winds in the morning, decreasing in the afternoon.
Monday Night Moderate to heavy rain and snow becoming showers after midnight. Strong W Pass level winds, extreme W ridgeline winds.
Tuesday Light to moderate snow showers in the morning, becoming more scattered showers in the afternoon. Strong ridgeline W winds at Pass and ridgeline level in the morning, decreasing to moderate in the afternoon.
Monday Night Moderate to heavy rain and snow becoming showers after midnight. Strong W Pass level winds, extreme W ridgeline winds.
Tuesday Light to moderate snow showers. Strong to extreme ridgeline W winds at Pass and ridgeline level in the morning, decreasing in the afternoon.
Monday Night Moderate rain and snow becoming showers after midnight. Strong to extreme ridgeline winds.
Tuesday Light to moderate snow showers in the morning and heaviest near the Cascade crest, becoming mostly cloudy and scattered showers in the afternoon. Strong ridgeline winds in the morning, decreasing to moderate in the afternoon.
Monday Night Moderate rain and snow becoming showers after midnight. Extreme winds ridgeline winds.
Tuesday Light to moderate snow showers in the morning and heaviest near the Cascade crest, becoming mostly cloudy and scattered showers in the afternoon. Strong to extreme ridgeline winds in the morning, decreasing in the afternoon.
Monday Night Moderate rain and snow becoming showers after midnight. Extreme winds ridgeline winds.
Tuesday Light to moderate snow showers in the morning and heaviest near the Cascade crest, becoming mostly cloudy and scattered showers in the afternoon. Strong to extreme ridgeline winds in the morning, decreasing to moderate in the afternoon.
Monday Night Moderate rain and snow becoming showers after midnight. Extreme winds ridgeline winds.
Tuesday Light to moderate snow showers. Strong to extreme ridgeline winds.

Issued: 2:07 PM PST Monday, February 20, 2023

Precipitation (in)

Monday Night Tuesday Tuesday Night Wednesday
4 pm - 4 am 4 am - 4 pm 4 pm - 4 am 4 am - 4 pm
Hurricane Ridge 0.25 - 0.50 0.50 LT 0.25 LT 0.10
Mt Baker Ski Area 0.75 -1.00 0.50 LT 0.10 LT 0.10
Mt. Loop - Barlow Pass 1.00 - 1.50 0.50 - 0.75 LT 0.25 LT 0.10
Stevens Pass 0.75 -1.00 0.50 LT 0.10 LT 0.10
Snoqualmie Pass 1.00 0.50 - 0.75 LT 0.25 LT 0.10
Crystal Mt 0.25 - 0.50 0.25 LT 0.10 LT 0.10
Paradise 1.00 0.75 LT 0.25 LT 0.10
White Pass 0.75 0.50 LT 0.25 LT 0.10
Washington Pass 0.50 - 0.75 LT 0.25 LT 0.10 LT 0.10
Mission Ridge 0.25 LT 0.10 LT 0.25 LT 0.10
Salmon la Sac - Gallagher Head 0.75 -1.00 0.25 - 0.50 LT 0.10 LT 0.10
Tieton River - Darland Mt. 0.50 0.25 - 0.50 LT 0.10 LT 0.10
Mt Hood Meadows 0.50 0.75 LT 0.25 LT 0.10
Timberline 0.75 -1.00 1.00 0.25 LT 0.10
Hurricane Ridge Precipitation (in)
Monday Night 0.25 - 0.50
Tuesday 0.50
Tuesday Night LT 0.25
Wednesday LT 0.10
Mt Baker Ski Area Precipitation (in)
Monday Night 0.75 -1.00
Tuesday 0.50
Tuesday Night LT 0.10
Wednesday LT 0.10
Mt. Loop - Barlow Pass Precipitation (in)
Monday Night 1.00 - 1.50
Tuesday 0.50 - 0.75
Tuesday Night LT 0.25
Wednesday LT 0.10
Stevens Pass Precipitation (in)
Monday Night 0.75 -1.00
Tuesday 0.50
Tuesday Night LT 0.10
Wednesday LT 0.10
Snoqualmie Pass Precipitation (in)
Monday Night 1.00
Tuesday 0.50 - 0.75
Tuesday Night LT 0.25
Wednesday LT 0.10
Crystal Mt Precipitation (in)
Monday Night 0.25 - 0.50
Tuesday 0.25
Tuesday Night LT 0.10
Wednesday LT 0.10
Paradise Precipitation (in)
Monday Night 1.00
Tuesday 0.75
Tuesday Night LT 0.25
Wednesday LT 0.10
White Pass Precipitation (in)
Monday Night 0.75
Tuesday 0.50
Tuesday Night LT 0.25
Wednesday LT 0.10
Washington Pass Precipitation (in)
Monday Night 0.50 - 0.75
Tuesday LT 0.25
Tuesday Night LT 0.10
Wednesday LT 0.10
Mission Ridge Precipitation (in)
Monday Night 0.25
Tuesday LT 0.10
Tuesday Night LT 0.25
Wednesday LT 0.10
Salmon la Sac - Gallagher Head Precipitation (in)
Monday Night 0.75 -1.00
Tuesday 0.25 - 0.50
Tuesday Night LT 0.10
Wednesday LT 0.10
Tieton River - Darland Mt. Precipitation (in)
Monday Night 0.50
Tuesday 0.25 - 0.50
Tuesday Night LT 0.10
Wednesday LT 0.10
Mt Hood Meadows Precipitation (in)
Monday Night 0.50
Tuesday 0.75
Tuesday Night LT 0.25
Wednesday LT 0.10
Timberline Precipitation (in)
Monday Night 0.75 -1.00
Tuesday 1.00
Tuesday Night 0.25
Wednesday LT 0.10

Issued: 2:07 PM PST Monday, February 20, 2023

Snow Level (ft)

Monday Evening Monday Night Tuesday Morning Tuesday Afternoon Tuesday Evening Tuesday Night* Wednesday Morning* Wednesday Afternoon*
Olympics 4500' 2000' 1500' 2000' 500' 0 500' 1000'
West North 3500' 2000' 1500' 2000' 1000' 0 0 500'
West Central 4500' 2000' 1500' 2000' 1000' 0 0 500'
West South 4500' 2500' 1500' 2000' 1000' 0 500' 1000'
Stevens Pass 4500' 2500' 1500' 2000' 1000' 0 0 500'
Snoqualmie Pass 4500' 2500' 1500' 2000' 1000' 0 0 500'
East North 4000' 2500' 1500' 2500' 500' 0 0 1000'
East Central 4500' 2500' 1500' 2500' 1000' 0 0 1000'
East South 5000' 3000' 1500' 2500' 1000' 0 500' 1000'
Mt. Hood 5500' 3000' 1500' 2000' 1000' 0 500' 1000'
Olympics Elevation
Monday Evening 4500'
Monday Night 2000'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Tuesday Evening 500'
Tuesday Night* 0'
Wednesday Morning* 500'
Wednesday Afternoon* 1000'
West North Elevation
Monday Evening 3500'
Monday Night 2000'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Tuesday Evening 1000'
Tuesday Night* 0'
Wednesday Morning* 0'
Wednesday Afternoon* 500'
West Central Elevation
Monday Evening 4500'
Monday Night 2000'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Tuesday Evening 1000'
Tuesday Night* 0'
Wednesday Morning* 0'
Wednesday Afternoon* 500'
West South Elevation
Monday Evening 4500'
Monday Night 2500'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Tuesday Evening 1000'
Tuesday Night* 0'
Wednesday Morning* 500'
Wednesday Afternoon* 1000'
Stevens Pass Elevation
Monday Evening 4500'
Monday Night 2500'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Tuesday Evening 1000'
Tuesday Night* 0'
Wednesday Morning* 0'
Wednesday Afternoon* 500'
Snoqualmie Pass Elevation
Monday Evening 4500'
Monday Night 2500'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Tuesday Evening 1000'
Tuesday Night* 0'
Wednesday Morning* 0'
Wednesday Afternoon* 500'
East North Elevation
Monday Evening 4000'
Monday Night 2500'
Tuesday Morning 1500'
Tuesday Afternoon 2500'
Tuesday Evening 500'
Tuesday Night* 0'
Wednesday Morning* 0'
Wednesday Afternoon* 1000'
East Central Elevation
Monday Evening 4500'
Monday Night 2500'
Tuesday Morning 1500'
Tuesday Afternoon 2500'
Tuesday Evening 1000'
Tuesday Night* 0'
Wednesday Morning* 0'
Wednesday Afternoon* 1000'
East South Elevation
Monday Evening 5000'
Monday Night 3000'
Tuesday Morning 1500'
Tuesday Afternoon 2500'
Tuesday Evening 1000'
Tuesday Night* 0'
Wednesday Morning* 500'
Wednesday Afternoon* 1000'
Mt. Hood Elevation
Monday Evening 5500'
Monday Night 3000'
Tuesday Morning 1500'
Tuesday Afternoon 2000'
Tuesday Evening 1000'
Tuesday Night* 0'
Wednesday Morning* 500'
Wednesday Afternoon* 1000'

Issued: 2:07 PM PST Monday, February 20, 2023

5000' Temperatures (°F)

Monday Night Tuesday
Max / Min Max / Min
Olympics 30 / 22 27 / 21
West North 29 / 22 27 / 21
West Central 29 / 22 27 / 22
West South 32 / 23 28 / 23
Stevens Pass 30 / 22 27 / 23
Snoqualmie Pass 30 / 22 27 / 22
East North 31 / 21 26 / 22
East Central 31 / 21 27 / 22
East South 32 / 21 27 / 21
Mt. Hood 33 / 23 28 / 22
Olympics 5000' Temperature Forecast
(Max / Min)
Monday Night 30 / 22
Tuesday 27 / 21
West North 5000' Temperature Forecast
(Max / Min)
Monday Night 29 / 22
Tuesday 27 / 21
West Central 5000' Temperature Forecast
(Max / Min)
Monday Night 29 / 22
Tuesday 27 / 22
West South 5000' Temperature Forecast
(Max / Min)
Monday Night 32 / 23
Tuesday 28 / 23
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Monday Night 30 / 22
Tuesday 27 / 23
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Monday Night 30 / 22
Tuesday 27 / 22
East North 5000' Temperature Forecast
(Max / Min)
Monday Night 31 / 21
Tuesday 26 / 22
East Central 5000' Temperature Forecast
(Max / Min)
Monday Night 31 / 21
Tuesday 27 / 22
East South 5000' Temperature Forecast
(Max / Min)
Monday Night 32 / 21
Tuesday 27 / 21
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Monday Night 33 / 23
Tuesday 28 / 22

Issued: 2:07 PM PST Monday, February 20, 2023

Ridgeline Winds (mph)

Monday Evening Monday Night Tuesday Morning Tuesday Afternoon
Olympics W 30-40 W 35-50 W 25-35 W 10-20
West North SW 30-40 W 20-30 W 15-25 W 5-15
West Central SW 25-35 W 30-40 W 20-30 W 10-20
West South W 40-55 W 35-50 W 30-40 W 20-30
Stevens Pass WSW 35-50 W 35-50 W 20-30 W 15-25
Snoqualmie Pass WSW 35-50 W 35-50 W 25-35 W 20-30
East North WSW 35-50 W 30-40 W 20-30 WNW 10-20
East Central WSW 40-55 W 40-55 W 35-50 WNW 20-30
East South WSW 35-50 W 40-55 W 30-40 WNW 15-25
Mt. Hood WSW 40-55 W 40-55 W 35-50 WNW 30-40
Olympics Ridgeline Winds (mph)
Monday Evening W 30-40
Monday Night W 35-50
Tuesday Morning W 25-35
Tuesday Afternoon W 10-20
West North Ridgeline Winds (mph)
Monday Evening SW 30-40
Monday Night W 20-30
Tuesday Morning W 15-25
Tuesday Afternoon W 5-15
West Central Ridgeline Winds (mph)
Monday Evening SW 25-35
Monday Night W 30-40
Tuesday Morning W 20-30
Tuesday Afternoon W 10-20
West South Ridgeline Winds (mph)
Monday Evening W 40-55
Monday Night W 35-50
Tuesday Morning W 30-40
Tuesday Afternoon W 20-30
Stevens Pass Ridgeline Winds (mph)
Monday Evening WSW 35-50
Monday Night W 35-50
Tuesday Morning W 20-30
Tuesday Afternoon W 15-25
Snoqualmie Pass Ridgeline Winds (mph)
Monday Evening WSW 35-50
Monday Night W 35-50
Tuesday Morning W 25-35
Tuesday Afternoon W 20-30
East North Ridgeline Winds (mph)
Monday Evening WSW 35-50
Monday Night W 30-40
Tuesday Morning W 20-30
Tuesday Afternoon WNW 10-20
East Central Ridgeline Winds (mph)
Monday Evening WSW 40-55
Monday Night W 40-55
Tuesday Morning W 35-50
Tuesday Afternoon WNW 20-30
East South Ridgeline Winds (mph)
Monday Evening WSW 35-50
Monday Night W 40-55
Tuesday Morning W 30-40
Tuesday Afternoon WNW 15-25
Mt. Hood Ridgeline Winds (mph)
Monday Evening WSW 40-55
Monday Night W 40-55
Tuesday Morning W 35-50
Tuesday Afternoon WNW 30-40

Issued: 2:07 PM PST Monday, February 20, 2023

Extended Weather Synopsis

Cold temperatures and E-SE winds will continue Wednesday night and begin to decrease Thursday as the upper trough begins to split off from the main upper level flow.  Thursday and Friday look to be cold and mainly dry (few flurries possible) days with variable cloud cover.  

Extended Snow Level (ft)

Wednesday Night* Thursday * Thursday Night* Friday
West North 0 500' 0 1000'
Snoqualmie Pass 0 500' 0 1000'
Mt. Hood 0 500' 0 1000'
West North Elevation
Wednesday Night* 0'
Thursday * 500'
Thursday Night* 0'
Friday 1000'
Snoqualmie Pass Elevation
Wednesday Night* 0'
Thursday * 500'
Thursday Night* 0'
Friday 1000'
Mt. Hood Elevation
Wednesday Night* 0'
Thursday * 500'
Thursday Night* 0'
Friday 1000'

Jump to: Weather Forecast I Precipitation I Snow Level I 5000' Temps I Ridgeline Winds I Extended Weather

Previous forecast from Feb 20, 2023

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.

The 5000’ temperature forecast does not imply a trend over the 12 hr period and only represents the max and min temperatures within a 12 hr period in the zone. The 6-hr snow level forecast, the forecast discussion, and weather forecast sections may add detail regarding temperature trends.

The snow level forecast represents the general snow level over a 6 hr time period. Freezing levels are forecast when precipitation is not expected.

*Easterly or offshore flow is highlighted with an asterisk when we expect relatively cool east winds in the major Cascade Passes. Easterly flow will often lead to temperature inversions and is a key variable for forecasting precipitation type in the Cascade Passes. Strong easterly flow events can affect terrain on a more regional scale.

Ridgeline winds are the average wind speed and direction over a 6 hr time period.

The wind forecast represents an elevation range instead of a single elevation slice. The elevation range overlaps with the near and above treeline elevation bands in the avalanche forecast and differs per zone.

Wind direction indicates the direction the wind originates or comes from on the 16-point compass rose.

Water Equivalent (WE) is the liquid water equivalent of all precipitation types; rain, snow, ice pellets, etc., forecast to the hundredth of an inch at specific locations. To use WE as a proxy for snowfall amounts, start with a snow to water ratio of 10:1 (10 inches of snow = 1 inch WE). Temperatures at or near freezing will generally have a lower ratio (heavy wet snow) and very cold temperatures can have a much higher ratio (dry fluffy snow).

The label LT, is shorthand for ‘less than’.