Most places will experience the proverbial "calm before the storm" Sunday evening. A few isolated showers could continue to bounce around the region overnight, primarily in the Olympics and locations close to the Canadian border. Everywhere else should see dry weather with increasing clouds and strengthening winds as our next weather system bears down on the Pacific Northwest.
The first in a series of very wet storms should arrive in the region right around sunrise spreading precipitation from NW to SE. This fast-moving front appears to bring moderate precipitation and strong ridgetop winds across the mountains with modest and short-lived spill over to trailheads further east. Snow levels stay relatively low (2500-3500') through this initial event.
Just as the first system exits the region Monday afternoon, the jet stream takes aim at Washington and Oregon. Several waves of precipitation fed by a sub-tropical moisture tap line up to impact the mountains. Warmer air, ushered in by the atmospheric river, should send snow levels on a steady climb upward. The question remains, how high will they go? Plenty of uncertainty lingers about the snowline during these storms. Cold air east of the crest eventually scours out causing all locations to experience mild conditions. Heavy precipitation spreads over the mountains Monday night into Tuesday with all areas receiving significant amounts of water. Rain and snow begin to lessen by Tuesday afternoon, but the active weather isn't over as we head into the extended forecast period.
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
Sunday
Night
Cloudy with isolated showers. Strong SW winds increasing overnight.
Monday
Cloudy with rain and snow. Strong SW winds in the morning.
Sunday
Night
Cloudy with scattered showers. Strong S winds increasing overnight,.
Monday
Cloudy. Moderate to heavy rain and snow. Strong S winds in the morning.
Sunday
Night
Cloudy with isolated showers. Strong SW winds increasing overnight.
Monday
Cloudy with moderate to heavy rain and snow. Strong SW winds in the morning.
Sunday
Night
Becoming cloudy. Moderate to strong SW winds increasing overnight.
Monday
Cloudy with rain and snow. Heaviest near the volcanoes. Strong SW winds.
Sunday
Night
Becoming cloudy. Light easterly flow at Pass level. Light to moderate S winds.
Monday
Cloudy with rain and snow. Light easterly flow at Pass level. Strong SW winds in the morning.
Cloudy light rain and snow. Strong W winds increasing during the day.
Issued: 1:58 PM PST Sunday, January 10, 2021
Precipitation (in)
Sunday Night
Monday
Monday Night
Tuesday
4 pm - 4 am
4 am - 4 pm
4 pm - 4 am
4 am - 4 pm
Hurricane Ridge
LT 0.25
0.25 - 0.50
1.00
0.50
Mt Baker Ski Area
0.25 - 0.50
0.75
1.00
1.00 - 1.50
Mt. Loop - Barlow Pass
LT 0.10
0.50 - 0.75
1.00
1.00
Stevens Pass
0
0.25 - 0.50
0.75
1.00
Snoqualmie Pass
0
0.50
1.00
1.00 - 1.50
Crystal Mt
0
0.25 - 0.50
0.75 -1.00
0.75 -1.00
Paradise
0
0.75 -1.00
1.50
1.50
White Pass
0
0.25 - 0.50
0.75
1.00
Washington Pass
LT 0.10
0.25
0.50
0.75 -1.00
Mission Ridge
0
LT 0.10
0.50
0.50
Salmon la Sac - Gallagher Head
0
0.25 - 0.50
0.75 -1.00
1.00
Tieton River - Darland Mt.
0
0.25
0.50 - 0.75
0.75
Mt Hood Meadows
0
0.25 - 0.50
1.00
1.00 - 1.50
Timberline
0
0.25 - 0.50
1.00
1.00 - 1.50
Hurricane Ridge
Precipitation (in)
Sunday Night
LT 0.25
Monday
0.25 - 0.50
Monday Night
1.00
Tuesday
0.50
Mt Baker Ski Area
Precipitation (in)
Sunday Night
0.25 - 0.50
Monday
0.75
Monday Night
1.00
Tuesday
1.00 - 1.50
Mt. Loop - Barlow Pass
Precipitation (in)
Sunday Night
LT 0.10
Monday
0.50 - 0.75
Monday Night
1.00
Tuesday
1.00
Stevens Pass
Precipitation (in)
Sunday Night
0
Monday
0.25 - 0.50
Monday Night
0.75
Tuesday
1.00
Snoqualmie Pass
Precipitation (in)
Sunday Night
0
Monday
0.50
Monday Night
1.00
Tuesday
1.00 - 1.50
Crystal Mt
Precipitation (in)
Sunday Night
0
Monday
0.25 - 0.50
Monday Night
0.75 -1.00
Tuesday
0.75 -1.00
Paradise
Precipitation (in)
Sunday Night
0
Monday
0.75 -1.00
Monday Night
1.50
Tuesday
1.50
White Pass
Precipitation (in)
Sunday Night
0
Monday
0.25 - 0.50
Monday Night
0.75
Tuesday
1.00
Washington Pass
Precipitation (in)
Sunday Night
LT 0.10
Monday
0.25
Monday Night
0.50
Tuesday
0.75 -1.00
Mission Ridge
Precipitation (in)
Sunday Night
0
Monday
LT 0.10
Monday Night
0.50
Tuesday
0.50
Salmon la Sac - Gallagher Head
Precipitation (in)
Sunday Night
0
Monday
0.25 - 0.50
Monday Night
0.75 -1.00
Tuesday
1.00
Tieton River - Darland Mt.
Precipitation (in)
Sunday Night
0
Monday
0.25
Monday Night
0.50 - 0.75
Tuesday
0.75
Mt Hood Meadows
Precipitation (in)
Sunday Night
0
Monday
0.25 - 0.50
Monday Night
1.00
Tuesday
1.00 - 1.50
Timberline
Precipitation (in)
Sunday Night
0
Monday
0.25 - 0.50
Monday Night
1.00
Tuesday
1.00 - 1.50
Issued: 1:58 PM PST Sunday, January 10, 2021
Snow Level (ft)
Sunday
Evening*
Sunday
Night*
Monday
Morning*
Monday
Afternoon*
Monday
Evening*
Monday
Night*
Tuesday
Morning
Tuesday
Afternoon
Olympics
4000'
4500'
4000'
3500'
4000'
5000'
6000'
4500'
West North
4000'
3500'
3500'
4000'
3000'
3000'
4000'
4500'
West Central
4000'
3500'
3000'
4000'
3500'
3000'
5000'
5500'
West South
4000'
4000'
4000'
4500'
4000'
4500'
6500'
6000'
Stevens Pass
3500'
3000'
2500'
4000'
3500'
3000'
5500'
5500'
Snoqualmie Pass
4000'
3000'
2500'
4000'
3500'
3500'
6000'
6000'
East North
2500'
2000'
2000'
3000'
3000'
2500'
2500'
3500'
East Central
3000'
2500'
2500'
3500'
3000'
3000'
3500'
6000'
East South
4000'
3500'
3500'
4500'
4000'
4000'
6000'
6000'
Mt. Hood
5500'
5500'
4500'
6000'
6000'
7000'
7500'
7500'
Olympics
Elevation
Sunday
Evening*
4000'
Sunday
Night*
4500'
Monday
Morning*
4000'
Monday
Afternoon*
3500'
Monday
Evening*
4000'
Monday
Night*
5000'
Tuesday
Morning
6000'
Tuesday
Afternoon
4500'
West North
Elevation
Sunday
Evening*
4000'
Sunday
Night*
3500'
Monday
Morning*
3500'
Monday
Afternoon*
4000'
Monday
Evening*
3000'
Monday
Night*
3000'
Tuesday
Morning
4000'
Tuesday
Afternoon
4500'
West Central
Elevation
Sunday
Evening*
4000'
Sunday
Night*
3500'
Monday
Morning*
3000'
Monday
Afternoon*
4000'
Monday
Evening*
3500'
Monday
Night*
3000'
Tuesday
Morning
5000'
Tuesday
Afternoon
5500'
West South
Elevation
Sunday
Evening*
4000'
Sunday
Night*
4000'
Monday
Morning*
4000'
Monday
Afternoon*
4500'
Monday
Evening*
4000'
Monday
Night*
4500'
Tuesday
Morning
6500'
Tuesday
Afternoon
6000'
Stevens Pass
Elevation
Sunday
Evening*
3500'
Sunday
Night*
3000'
Monday
Morning*
2500'
Monday
Afternoon*
4000'
Monday
Evening*
3500'
Monday
Night*
3000'
Tuesday
Morning
5500'
Tuesday
Afternoon
5500'
Snoqualmie Pass
Elevation
Sunday
Evening*
4000'
Sunday
Night*
3000'
Monday
Morning*
2500'
Monday
Afternoon*
4000'
Monday
Evening*
3500'
Monday
Night*
3500'
Tuesday
Morning
6000'
Tuesday
Afternoon
6000'
East North
Elevation
Sunday
Evening*
2500'
Sunday
Night*
2000'
Monday
Morning*
2000'
Monday
Afternoon*
3000'
Monday
Evening*
3000'
Monday
Night*
2500'
Tuesday
Morning
2500'
Tuesday
Afternoon
3500'
East Central
Elevation
Sunday
Evening*
3000'
Sunday
Night*
2500'
Monday
Morning*
2500'
Monday
Afternoon*
3500'
Monday
Evening*
3000'
Monday
Night*
3000'
Tuesday
Morning
3500'
Tuesday
Afternoon
6000'
East South
Elevation
Sunday
Evening*
4000'
Sunday
Night*
3500'
Monday
Morning*
3500'
Monday
Afternoon*
4500'
Monday
Evening*
4000'
Monday
Night*
4000'
Tuesday
Morning
6000'
Tuesday
Afternoon
6000'
Mt. Hood
Elevation
Sunday
Evening*
5500'
Sunday
Night*
5500'
Monday
Morning*
4500'
Monday
Afternoon*
6000'
Monday
Evening*
6000'
Monday
Night*
7000'
Tuesday
Morning
7500'
Tuesday
Afternoon
7500'
Issued: 1:58 PM PST Sunday, January 10, 2021
5000' Temperatures (°F)
Sunday
Night
Monday
Max / Min
Max / Min
Olympics
32 / 29
31 / 30
West North
30 / 30
31 / 29
West Central
30 / 29
32 / 28
West South
34 / 31
33 / 32
Stevens Pass
29 / 25
32 / 25
Snoqualmie Pass
30 / 26
32 / 27
East North
26 / 24
32 / 24
East Central
29 / 26
32 / 27
East South
31 / 27
34 / 28
Mt. Hood
34 / 31
35 / 32
Olympics
5000' Temperature Forecast (Max / Min)
Sunday
Night
32 / 29
Monday
31 / 30
West North
5000' Temperature Forecast (Max / Min)
Sunday
Night
30 / 30
Monday
31 / 29
West Central
5000' Temperature Forecast (Max / Min)
Sunday
Night
30 / 29
Monday
32 / 28
West South
5000' Temperature Forecast (Max / Min)
Sunday
Night
34 / 31
Monday
33 / 32
Stevens Pass
5000' Temperature Forecast (Max / Min)
Sunday
Night
29 / 25
Monday
32 / 25
Snoqualmie Pass
5000' Temperature Forecast (Max / Min)
Sunday
Night
30 / 26
Monday
32 / 27
East North
5000' Temperature Forecast (Max / Min)
Sunday
Night
26 / 24
Monday
32 / 24
East Central
5000' Temperature Forecast (Max / Min)
Sunday
Night
29 / 26
Monday
32 / 27
East South
5000' Temperature Forecast (Max / Min)
Sunday
Night
31 / 27
Monday
34 / 28
Mt. Hood
5000' Temperature Forecast (Max / Min)
Sunday
Night
34 / 31
Monday
35 / 32
Issued: 1:58 PM PST Sunday, January 10, 2021
Ridgeline Winds (mph)
Sunday
Evening
Sunday
Night
Monday
Morning
Monday
Afternoon
Olympics
SSW 30-40
SW 40-55
SW 40-55
W 20-30
West North
S 30-40
S 35-50
S 40-55
W 20-30
West Central
SSW 20-30
SSW 25-35
WSW 35-50
W 15-25
West South
SW 15-25
SW 20-30
SW 35-50
W 25-35
Stevens Pass
S 10-20
SSW 10-20
SW 25-35
W 20-30
Snoqualmie Pass
SSW 20-30
SSW 15-25
SW 30-40
W 20-30
East North
SW 15-25
SW 15-25
SW 25-35
W 20-30
East Central
SW 15-25
SW 25-35
SW 30-40
W 30-40
East South
SW 20-30
SW 25-35
WSW 30-40
W 40-55
Mt. Hood
SW 15-25
SW 30-40
WSW 35-50
W 40-55
Olympics
Ridgeline Winds (mph)
Sunday
Evening
SSW
30-40
Sunday
Night
SW
40-55
Monday
Morning
SW
40-55
Monday
Afternoon
W
20-30
West North
Ridgeline Winds (mph)
Sunday
Evening
S
30-40
Sunday
Night
S
35-50
Monday
Morning
S
40-55
Monday
Afternoon
W
20-30
West Central
Ridgeline Winds (mph)
Sunday
Evening
SSW
20-30
Sunday
Night
SSW
25-35
Monday
Morning
WSW
35-50
Monday
Afternoon
W
15-25
West South
Ridgeline Winds (mph)
Sunday
Evening
SW
15-25
Sunday
Night
SW
20-30
Monday
Morning
SW
35-50
Monday
Afternoon
W
25-35
Stevens Pass
Ridgeline Winds (mph)
Sunday
Evening
S
10-20
Sunday
Night
SSW
10-20
Monday
Morning
SW
25-35
Monday
Afternoon
W
20-30
Snoqualmie Pass
Ridgeline Winds (mph)
Sunday
Evening
SSW
20-30
Sunday
Night
SSW
15-25
Monday
Morning
SW
30-40
Monday
Afternoon
W
20-30
East North
Ridgeline Winds (mph)
Sunday
Evening
SW
15-25
Sunday
Night
SW
15-25
Monday
Morning
SW
25-35
Monday
Afternoon
W
20-30
East Central
Ridgeline Winds (mph)
Sunday
Evening
SW
15-25
Sunday
Night
SW
25-35
Monday
Morning
SW
30-40
Monday
Afternoon
W
30-40
East South
Ridgeline Winds (mph)
Sunday
Evening
SW
20-30
Sunday
Night
SW
25-35
Monday
Morning
WSW
30-40
Monday
Afternoon
W
40-55
Mt. Hood
Ridgeline Winds (mph)
Sunday
Evening
SW
15-25
Sunday
Night
SW
30-40
Monday
Morning
WSW
35-50
Monday
Afternoon
W
40-55
Issued: 1:58 PM PST Sunday, January 10, 2021
Extended Weather Synopsis
With an atmospheric river pointed at the Washington/Oregon border, expect relatively warm and wet weather. A developing low pressure rides the jet stream and brings another round of moderate to heavy rain and snow to the mountains Tuesday night into Wednesday. At the moment, this event appears the wettest of all three waves of precipitation. After several days of active weather and a thorough soaking, a high-pressure ridge begins to build over the Pacific Northwest. This ridge should give us a chance to dry out and see a return to sunshine.
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).