Issued: 2:09 PM PST Monday, December 19, 2022
by Dennis D'Amico

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

Weather Synopsis

Precipitation out ahead of a developing warm front has already transitioned the mountains from scattered showers to steady light snow in many areas this afternoon. This trend will continue overnight as a low pressure system deepens and tracks toward our region.  This system will move fast in westerly zonal flow but punch a significant punch. Heavier snowfall will develop for the northern and central Cascades in the morning, and shift south in the afternoon as a cold front sweeps through around mid-day or early afternoon. 

As this system slams into arctic air entrenched along the Washington Cascades, we can squeeze out more low density snowfall than our usual storms.  Storm totals will likely be 1 to 2.5 ft range for most areas through Tuesday afternoon. Some warming will occur down near Mt Hood, and to a lesser extent for the southern Washington Cascades mid-day through early Tuesday afternoon.  

Subtle storm track variations are likely to nudge the higher storm totals north or south as the event occurs. Strong to extreme W-SW winds will develop to the south of the low pressure system. Look for winds to increase during the day on Tuesday.  

Showers and a possible PSCZ will add a few more fluffy inches Tuesday night.  A ridge will build offshore on Wednesday and bring our region a drying trend. Very cold air will once again settle over the area with mountain temperatures generally in the single digits. 

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 snow developing and becoming moderate by late tonight. Winds becoming strong.
Tuesday Stormy with moderate to occasionally heavy snow becoming scattered snow showers in the afternoon.
Monday Night Light snow developing and becoming moderate by late tonight. Winds becoming strong.
Tuesday Windy with moderate to possibly heavy snow in the morning, then becoming scattered snow showers in the afternoon.
Monday Night Light snow developing and becoming moderate by late tonight. Winds becoming strong.
Tuesday Windy with moderate to occasionally heavy snow.
Monday Night Light snow developing overnight. Winds becoming strong.
Tuesday Light to moderate snow developing during the morning. Strong ridgeline winds.
Monday Night Light snow developing and becoming moderate late. Ridgeline winds becoming strong out of the west. Light East winds at Pass level.
Tuesday Moderate to occasionally heavy snow. Strong west winds at ridgeline, light east winds at Pass level.
Monday Night Light snow developing and becoming light to moderate late. Ridgeline winds becoming strong out of the west. Light East winds at Pass level.
Tuesday Moderate to occasionally heavy snow. Strong west winds at ridgeline, light east winds at Pass level.
Monday Night Cloudy with light snow developing overnight and becoming moderate late tonight. Moderate ridgeline winds.
Tuesday Windy with moderate to possibly heavy snow in the morning, then becoming scattered snow showers late in the afternoon.
Monday Night Cloudy with light snow developing overnight. Moderate ridgeline winds.
Tuesday Light to moderate snow developing in the morning. Strong ridgeline winds.
Monday Night Cloudy with light snow developing overnight. Moderate ridgeline winds.
Tuesday Light to moderate snow developing mid-day. Strong ridgeline winds.
Monday Night Cloudy with light snow developing overnight. Moderate to strong ridgeline winds.
Tuesday Light to moderate snow developing mid-day. Strong ridgeline winds.

Issued: 2:09 PM PST Monday, December 19, 2022

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 - 0.75 LT 0.10 0
Mt Baker Ski Area 0.25 0.75 -1.00 LT 0.10 0
Mt. Loop - Barlow Pass 0.25 - 0.50 1.00 LT 0.25 LT 0.10
Stevens Pass 0.25 0.75 -1.00 0.25 LT 0.10
Snoqualmie Pass 0.25 - 0.50 1.00 0.25 LT 0.10
Crystal Mt LT 0.25 0.25 - 0.50 LT 0.25 LT 0.10
Paradise 0.25 0.75 -1.00 0.25 LT 0.10
White Pass LT 0.25 0.50 - 0.75 0.25 LT 0.10
Washington Pass LT 0.25 0.50 - 0.75 0 0
Mission Ridge LT 0.10 0.25 0 0
Salmon la Sac - Gallagher Head LT 0.25 0.75 LT 0.25 LT 0.10
Tieton River - Darland Mt. LT 0.10 0.25 - 0.50 LT 0.25 LT 0.10
Mt Hood Meadows LT 0.10 0.50 - 0.75 1.00 LT 0.25
Timberline LT 0.10 0.75 1.00 - 1.50 LT 0.25
Hurricane Ridge Precipitation (in)
Monday Night 0.25
Tuesday 0.50 - 0.75
Tuesday Night LT 0.10
Wednesday 0
Mt Baker Ski Area Precipitation (in)
Monday Night 0.25
Tuesday 0.75 -1.00
Tuesday Night LT 0.10
Wednesday 0
Mt. Loop - Barlow Pass Precipitation (in)
Monday Night 0.25 - 0.50
Tuesday 1.00
Tuesday Night LT 0.25
Wednesday LT 0.10
Stevens Pass Precipitation (in)
Monday Night 0.25
Tuesday 0.75 -1.00
Tuesday Night 0.25
Wednesday LT 0.10
Snoqualmie Pass Precipitation (in)
Monday Night 0.25 - 0.50
Tuesday 1.00
Tuesday Night 0.25
Wednesday LT 0.10
Crystal Mt Precipitation (in)
Monday Night LT 0.25
Tuesday 0.25 - 0.50
Tuesday Night LT 0.25
Wednesday LT 0.10
Paradise Precipitation (in)
Monday Night 0.25
Tuesday 0.75 -1.00
Tuesday Night 0.25
Wednesday LT 0.10
White Pass Precipitation (in)
Monday Night LT 0.25
Tuesday 0.50 - 0.75
Tuesday Night 0.25
Wednesday LT 0.10
Washington Pass Precipitation (in)
Monday Night LT 0.25
Tuesday 0.50 - 0.75
Tuesday Night 0
Wednesday 0
Mission Ridge Precipitation (in)
Monday Night LT 0.10
Tuesday 0.25
Tuesday Night 0
Wednesday 0
Salmon la Sac - Gallagher Head Precipitation (in)
Monday Night LT 0.25
Tuesday 0.75
Tuesday Night LT 0.25
Wednesday LT 0.10
Tieton River - Darland Mt. Precipitation (in)
Monday Night LT 0.10
Tuesday 0.25 - 0.50
Tuesday Night LT 0.25
Wednesday LT 0.10
Mt Hood Meadows Precipitation (in)
Monday Night LT 0.10
Tuesday 0.50 - 0.75
Tuesday Night 1.00
Wednesday LT 0.25
Timberline Precipitation (in)
Monday Night LT 0.10
Tuesday 0.75
Tuesday Night 1.00 - 1.50
Wednesday LT 0.25

Issued: 2:09 PM PST Monday, December 19, 2022

Snow Level (ft)

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

Issued: 2:09 PM PST Monday, December 19, 2022

5000' Temperatures (°F)

Monday Night Tuesday
Max / Min Max / Min
Olympics 23 / 13 25 / 15
West North 14 / 7 17 / 7
West Central 17 / 13 21 / 11
West South 22 / 14 27 / 22
Stevens Pass 13 / 7 20 / 12
Snoqualmie Pass 16 / 11 22 / 15
East North 5 / 1 13 / 2
East Central 11 / 8 21 / 13
East South 19 / 14 27 / 19
Mt. Hood 23 / 21 29 / 21
Olympics 5000' Temperature Forecast
(Max / Min)
Monday Night 23 / 13
Tuesday 25 / 15
West North 5000' Temperature Forecast
(Max / Min)
Monday Night 14 / 7
Tuesday 17 / 7
West Central 5000' Temperature Forecast
(Max / Min)
Monday Night 17 / 13
Tuesday 21 / 11
West South 5000' Temperature Forecast
(Max / Min)
Monday Night 22 / 14
Tuesday 27 / 22
Stevens Pass 5000' Temperature Forecast
(Max / Min)
Monday Night 13 / 7
Tuesday 20 / 12
Snoqualmie Pass 5000' Temperature Forecast
(Max / Min)
Monday Night 16 / 11
Tuesday 22 / 15
East North 5000' Temperature Forecast
(Max / Min)
Monday Night 5 / 1
Tuesday 13 / 2
East Central 5000' Temperature Forecast
(Max / Min)
Monday Night 11 / 8
Tuesday 21 / 13
East South 5000' Temperature Forecast
(Max / Min)
Monday Night 19 / 14
Tuesday 27 / 19
Mt. Hood 5000' Temperature Forecast
(Max / Min)
Monday Night 23 / 21
Tuesday 29 / 21

Issued: 2:09 PM PST Monday, December 19, 2022

Ridgeline Winds (mph)

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

Issued: 2:09 PM PST Monday, December 19, 2022

Extended Weather Synopsis

The ridge will hold Wednesday night and begin to shift inland on Thursday.  A series of frontal systems will crash into the ridge, with light snow developing Thursday or Thursday night.  Very strong offshore flow will lead to strong east gradients cranking that cold air through the Passes Wednesday night through Thursday night. Another frontal system should arrive Friday. Eventually, milder air will work into the area late this week west of the crest and likely over the weekend for the Passes and east slopes of the Cascades. 

Extended Snow Level (ft)

Wednesday Night* Thursday * Thursday Night* Friday *
West North 0 0 0 3000'
Snoqualmie Pass 0 0 0 3000'
Mt. Hood 0 0 1000' 5500'
West North Elevation
Wednesday Night* 0'
Thursday * 0'
Thursday Night* 0'
Friday * 3000'
Snoqualmie Pass Elevation
Wednesday Night* 0'
Thursday * 0'
Thursday Night* 0'
Friday * 3000'
Mt. Hood Elevation
Wednesday Night* 0'
Thursday * 0'
Thursday Night* 1000'
Friday * 5500'

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

Previous forecast from Dec 19, 2022

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’.