Following a cold and snowy period, the active weather patterns turns up the moisture dial and the temperatures as well: we're bracing for two atmospheric river events.
Saturday evening light snow showers continue to taper in post-frontal westerly flow as slightly cooler air settles in.
An approaching warm front begins to lift northward in the early morning hours. Warming and steady precipitation start first at Mt Hood with increasing rain and snow as snow levels rise. By morning, expect snow levels there to be above 7000 ft. While the heaviest precipitation will focus on Mt Hood on Sunday (where 24-hour precipitation totals could be in the 3-3.5" range), the southern Washington Cascades will also receive 1-2" of precipitation as snow changes to rain at most low and mid elevations from south to north as the day progresses. This transition will be particularly messy at the Cascade Passes where low-level E flow in the morning could create freezing rain or sleet in the mid-morning hours as the warm air over-runs it. By late in the day, W winds will overwhelm the cold air pool in most areas, except perhaps Washington Pass where there is a 50/50 chance precipitation stays all snow.
A cold front pushing through Sunday afternoon brings slightly cooler conditions, with light rain and snow showers along the west slopes of the Cascades Sunday night.
The second atmospheric river approaches on Monday with more rain and further increases in snow levels along with E winds. This time, the cold pool east of the Cascades will be very week and not particularly relevant.
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
Saturday
Night
Light snow showers in the evening. Light snow developing overnight. Light to occasionally moderate ridgeline winds.
Sunday
Light to moderate rain and snow in the morning. Rising snow levels. Moderate ridgeline winds.
Saturday
Night
Decreasing light snow showers tapering to flurries after midnight. Light ridgeline winds.
Sunday
Increasing rain snow along with rising snow levels in the morning, then becoming light rain and snow showers late in the day. Increasing moderate winds.
Saturday
Night
Decreasing light to moderate snow showers tapering to flurries after midnight. Light to moderate ridgeline winds becoming light overnight.
Sunday
Increasing moderate to heavy rain and snow along with rising snow levels, then moderate rain and snow showers in the afternoon. Light to moderate ridgeline winds.
Saturday
Night
Light showers in the evening with light snow developing in the early morning hours. Light to moderate ridgeline winds become light.
Sunday
Heavy rain and snow along with rising snow levels with moderate rain and snow showers in the afternoon. Moderate ridgeline winds.
Saturday
Night
Decreasing light to moderate snow showers tapering to flurries after midnight. Moderate ridgeline winds become light. Light W wind at the Pass switches E in the early morning hours.
Sunday
Moderate to heavy to start with a wintry mix likely late morning, then a changeover to rain. Ridgeline winds increase into the moderate range by the afternoon. Mostly light E winds switch W at the Pass by the afternoon.
Saturday
Night
Decreasing light to moderate snow showers tapering to flurries after midnight. Moderate ridgeline winds become light. Light to moderate W wind in the early evening becomes light overnight at the Pass switches E in the early morning hours.
Sunday
Heavy snow to start with a wintry mix likely mid-morning, then a changeover to rain. Ridgeline winds increase into the moderate range by mid-morning. Mostly light E winds switch W at the Pass by the afternoon.
Moderate snow, mixing with and then changing to rain. Increasing moderate ridgeline winds.
Saturday
Night
Snow flurries in the evening, then light snow develops in the early morning hours. Decreasing light to moderate ridgeline winds.
Sunday
Increasing light to moderate snow changing to rain at lower and middle elevations by the afternoon. Ridgeline winds increasing into the moderate range.
Saturday
Night
Light snow becoming moderate to heavy overnight. Moderate to strong ridgeline winds.
Sunday
Very heavy rain and high-elevation snow. Strong ridgeline winds.
Issued: 2:14 PM PST Saturday, December 2, 2023
Precipitation (in)
Saturday Night
Sunday
Sunday Night
Monday
4 pm - 4 am
4 am - 4 pm
4 pm - 4 am
4 am - 4 pm
Hurricane Ridge
LT 0.10
0.25
LT 0.10
0.50
Mt Baker Ski Area
LT 0.10
0.50
LT 0.10
0.75
Mt. Loop - Barlow Pass
LT 0.25
1.00
LT 0.10
1.00
Stevens Pass
LT 0.25
1.00
LT 0.10
0.75
Snoqualmie Pass
LT 0.25
1.50
LT 0.10
1.00
Crystal Mt
LT 0.10
0.50
LT 0.10
0.50
Paradise
0.25
2.00
LT 0.25
1.50
White Pass
LT 0.25
1.00
LT 0.25
0.50
Washington Pass
LT 0.10
0.50 - 0.75
LT 0.10
0.25 - 0.50
Mission Ridge
0
0.25 - 0.50
0
0.25 - 0.50
Salmon la Sac - Gallagher Head
LT 0.10
0.75 -1.00
LT 0.10
0.50 - 0.75
Tieton River - Darland Mt.
LT 0.10
0.50
LT 0.10
0.50
Mt Hood Meadows
0.75 -1.00
2.50 - 3.50
0.25 - 0.50
0.75
Timberline
1.00
3.00 - 4.00
0.50
0.75
Hurricane Ridge
Precipitation (in)
Saturday Night
LT 0.10
Sunday
0.25
Sunday Night
LT 0.10
Monday
0.50
Mt Baker Ski Area
Precipitation (in)
Saturday Night
LT 0.10
Sunday
0.50
Sunday Night
LT 0.10
Monday
0.75
Mt. Loop - Barlow Pass
Precipitation (in)
Saturday Night
LT 0.25
Sunday
1.00
Sunday Night
LT 0.10
Monday
1.00
Stevens Pass
Precipitation (in)
Saturday Night
LT 0.25
Sunday
1.00
Sunday Night
LT 0.10
Monday
0.75
Snoqualmie Pass
Precipitation (in)
Saturday Night
LT 0.25
Sunday
1.50
Sunday Night
LT 0.10
Monday
1.00
Crystal Mt
Precipitation (in)
Saturday Night
LT 0.10
Sunday
0.50
Sunday Night
LT 0.10
Monday
0.50
Paradise
Precipitation (in)
Saturday Night
0.25
Sunday
2.00
Sunday Night
LT 0.25
Monday
1.50
White Pass
Precipitation (in)
Saturday Night
LT 0.25
Sunday
1.00
Sunday Night
LT 0.25
Monday
0.50
Washington Pass
Precipitation (in)
Saturday Night
LT 0.10
Sunday
0.50 - 0.75
Sunday Night
LT 0.10
Monday
0.25 - 0.50
Mission Ridge
Precipitation (in)
Saturday Night
0
Sunday
0.25 - 0.50
Sunday Night
0
Monday
0.25 - 0.50
Salmon la Sac - Gallagher Head
Precipitation (in)
Saturday Night
LT 0.10
Sunday
0.75 -1.00
Sunday Night
LT 0.10
Monday
0.50 - 0.75
Tieton River - Darland Mt.
Precipitation (in)
Saturday Night
LT 0.10
Sunday
0.50
Sunday Night
LT 0.10
Monday
0.50
Mt Hood Meadows
Precipitation (in)
Saturday Night
0.75 -1.00
Sunday
2.50 - 3.50
Sunday Night
0.25 - 0.50
Monday
0.75
Timberline
Precipitation (in)
Saturday Night
1.00
Sunday
3.00 - 4.00
Sunday Night
0.50
Monday
0.75
Issued: 2:14 PM PST Saturday, December 2, 2023
Snow Level (ft)
Saturday
Evening
Saturday
Night*
Sunday
Morning*
Sunday
Afternoon*
Sunday
Evening
Sunday
Night
Monday
Morning*
Monday
Afternoon*
Olympics
3000'
2500'
5000'
6500'
4000'
4000'
6000'
8500'
West North
2500'
2000'
2500'
4000'
3500'
3000'
3500'
6000'
West Central
2500'
2500'
2500'
5500'
4000'
3000'
3500'
6500'
West South
3000'
2500'
4500'
7000'
5500'
3500'
4000'
8000'
Stevens Pass
2500'
2000'
2000'
4500'
4500'
3000'
3000'
5500'
Snoqualmie Pass
3000'
2500'
3000'
5500'
4500'
3000'
3000'
7000'
East North
2000'
1000'
1000'
3500'
3500'
2000'
2500'
4500'
East Central
2500'
1500'
2500'
4500'
5000'
3000'
3000'
5500'
East South
3000'
2500'
4000'
7000'
6000'
4000'
5000'
8000'
Mt. Hood
3500'
4500'
7000'
8000'
6000'
7000'
8000'
9000'
Olympics
Elevation
Saturday
Evening
3000'
Saturday
Night*
2500'
Sunday
Morning*
5000'
Sunday
Afternoon*
6500'
Sunday
Evening
4000'
Sunday
Night
4000'
Monday
Morning*
6000'
Monday
Afternoon*
8500'
West North
Elevation
Saturday
Evening
2500'
Saturday
Night*
2000'
Sunday
Morning*
2500'
Sunday
Afternoon*
4000'
Sunday
Evening
3500'
Sunday
Night
3000'
Monday
Morning*
3500'
Monday
Afternoon*
6000'
West Central
Elevation
Saturday
Evening
2500'
Saturday
Night*
2500'
Sunday
Morning*
2500'
Sunday
Afternoon*
5500'
Sunday
Evening
4000'
Sunday
Night
3000'
Monday
Morning*
3500'
Monday
Afternoon*
6500'
West South
Elevation
Saturday
Evening
3000'
Saturday
Night*
2500'
Sunday
Morning*
4500'
Sunday
Afternoon*
7000'
Sunday
Evening
5500'
Sunday
Night
3500'
Monday
Morning*
4000'
Monday
Afternoon*
8000'
Stevens Pass
Elevation
Saturday
Evening
2500'
Saturday
Night*
2000'
Sunday
Morning*
2000'
Sunday
Afternoon*
4500'
Sunday
Evening
4500'
Sunday
Night
3000'
Monday
Morning*
3000'
Monday
Afternoon*
5500'
Snoqualmie Pass
Elevation
Saturday
Evening
3000'
Saturday
Night*
2500'
Sunday
Morning*
3000'
Sunday
Afternoon*
5500'
Sunday
Evening
4500'
Sunday
Night
3000'
Monday
Morning*
3000'
Monday
Afternoon*
7000'
East North
Elevation
Saturday
Evening
2000'
Saturday
Night*
1000'
Sunday
Morning*
1000'
Sunday
Afternoon*
3500'
Sunday
Evening
3500'
Sunday
Night
2000'
Monday
Morning*
2500'
Monday
Afternoon*
4500'
East Central
Elevation
Saturday
Evening
2500'
Saturday
Night*
1500'
Sunday
Morning*
2500'
Sunday
Afternoon*
4500'
Sunday
Evening
5000'
Sunday
Night
3000'
Monday
Morning*
3000'
Monday
Afternoon*
5500'
East South
Elevation
Saturday
Evening
3000'
Saturday
Night*
2500'
Sunday
Morning*
4000'
Sunday
Afternoon*
7000'
Sunday
Evening
6000'
Sunday
Night
4000'
Monday
Morning*
5000'
Monday
Afternoon*
8000'
Mt. Hood
Elevation
Saturday
Evening
3500'
Saturday
Night*
4500'
Sunday
Morning*
7000'
Sunday
Afternoon*
8000'
Sunday
Evening
6000'
Sunday
Night
7000'
Monday
Morning*
8000'
Monday
Afternoon*
9000'
Issued: 2:14 PM PST Saturday, December 2, 2023
5000' Temperatures (°F)
Saturday
Night
Sunday
Max / Min
Max / Min
Olympics
33 / 26
38 / 29
Olympics
33 / 26
38 / 29
West North
25 / 24
35 / 28
West Central
28 / 26
38 / 29
West South
30 / 24
39 / 30
Stevens Pass
26 / 23
38 / 26
Snoqualmie Pass
27 / 23
38 / 27
East North
21 / 18
33 / 21
East South
29 / 24
39 / 29
Mt. Hood
36 / 29
41 / 36
Olympics
5000' Temperature Forecast (Max / Min)
Saturday
Night
33 / 26
Sunday
38 / 29
Olympics
5000' Temperature Forecast (Max / Min)
Saturday
Night
33 / 26
Sunday
38 / 29
West North
5000' Temperature Forecast (Max / Min)
Saturday
Night
25 / 24
Sunday
35 / 28
West Central
5000' Temperature Forecast (Max / Min)
Saturday
Night
28 / 26
Sunday
38 / 29
West South
5000' Temperature Forecast (Max / Min)
Saturday
Night
30 / 24
Sunday
39 / 30
Stevens Pass
5000' Temperature Forecast (Max / Min)
Saturday
Night
26 / 23
Sunday
38 / 26
Snoqualmie Pass
5000' Temperature Forecast (Max / Min)
Saturday
Night
27 / 23
Sunday
38 / 27
East North
5000' Temperature Forecast (Max / Min)
Saturday
Night
21 / 18
Sunday
33 / 21
East South
5000' Temperature Forecast (Max / Min)
Saturday
Night
29 / 24
Sunday
39 / 29
Mt. Hood
5000' Temperature Forecast (Max / Min)
Saturday
Night
36 / 29
Sunday
41 / 36
Issued: 2:14 PM PST Saturday, December 2, 2023
Ridgeline Winds (mph)
Saturday
Evening
Saturday
Night
Sunday
Morning
Sunday
Afternoon
Olympics
SW 10-20
SSW 5-15
SW 15-25
WSW 15-25
West North
W 10-20
SSW 5-15
SSW 15-25
SW 20-30
West Central
W 10-20
SSW 5-15
SSE 10-20
WSW 15-25
West South
WSW 10-20
SSW 5-15
SW 5-15
WSW 15-25
Stevens Pass
W 15-25
SW 5-15
S 5-15
WSW 15-25
Snoqualmie Pass
W 20-30
SSW 5-15
SE 5-15
W 20-30
East North
W 10-20
SW 5-15
S 5-15
WSW 20-30
East Central
W 20-30
WSW 10-20
SW 10-20
WSW 25-35
East South
W 10-20
WSW 5-15
SW 10-20
WSW 15-25
Mt. Hood
WSW 25-35
WSW 20-30
WSW 25-35
WSW 30-40
Olympics
Ridgeline Winds (mph)
Saturday
Evening
SW
10-20
Saturday
Night
SSW
5-15
Sunday
Morning
SW
15-25
Sunday
Afternoon
WSW
15-25
West North
Ridgeline Winds (mph)
Saturday
Evening
W
10-20
Saturday
Night
SSW
5-15
Sunday
Morning
SSW
15-25
Sunday
Afternoon
SW
20-30
West Central
Ridgeline Winds (mph)
Saturday
Evening
W
10-20
Saturday
Night
SSW
5-15
Sunday
Morning
SSE
10-20
Sunday
Afternoon
WSW
15-25
West South
Ridgeline Winds (mph)
Saturday
Evening
WSW
10-20
Saturday
Night
SSW
5-15
Sunday
Morning
SW
5-15
Sunday
Afternoon
WSW
15-25
Stevens Pass
Ridgeline Winds (mph)
Saturday
Evening
W
15-25
Saturday
Night
SW
5-15
Sunday
Morning
S
5-15
Sunday
Afternoon
WSW
15-25
Snoqualmie Pass
Ridgeline Winds (mph)
Saturday
Evening
W
20-30
Saturday
Night
SSW
5-15
Sunday
Morning
SE
5-15
Sunday
Afternoon
W
20-30
East North
Ridgeline Winds (mph)
Saturday
Evening
W
10-20
Saturday
Night
SW
5-15
Sunday
Morning
S
5-15
Sunday
Afternoon
WSW
20-30
East Central
Ridgeline Winds (mph)
Saturday
Evening
W
20-30
Saturday
Night
WSW
10-20
Sunday
Morning
SW
10-20
Sunday
Afternoon
WSW
25-35
East South
Ridgeline Winds (mph)
Saturday
Evening
W
10-20
Saturday
Night
WSW
5-15
Sunday
Morning
SW
10-20
Sunday
Afternoon
WSW
15-25
Mt. Hood
Ridgeline Winds (mph)
Saturday
Evening
WSW
25-35
Saturday
Night
WSW
20-30
Sunday
Morning
WSW
25-35
Sunday
Afternoon
WSW
30-40
Issued: 2:14 PM PST Saturday, December 2, 2023
Extended Weather Synopsis
The majority of the second atmospheric river arrives Monday night warm front pushing snow levels up to around 9000 ft. The heaviest precipitation arrives late Monday night and early Tuesday before a cold front eases southward Tuesday afternoon. The cold front and associated moisture linger on Tuesday night over Mt Hood with cooling temperatures bringing chances for snowfall once again by Wednesday.
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).