Precipitation associated with a Pacific frontal system has spread over the area today. So far precipitation has been lighter north of the jet stream over Washington state with the jet pointed into Oregon. Precipitation should start to increase for all areas as the front pushes inland this evening, passing through the Cascades around 10 pm. With a switch to westerlies in the Cascade Passes, we'll see a brief bump in snow levels to about 2500' around midnight.
Showers will increase tonight with strong westerly ridgeline winds across the area. A trailing trough will help invigorate shower activity through Friday morning; 4-10 inches of snow is likely tonight with closer to a foot possible near Mt. Hood. A convergence zone may form at times, especially Friday morning in the vicinity of the Mt Loop Hwy. The convergence zone is not expected to shift south to I-90.
Showers will continue but ease in intensity on Friday as westerly flow weakens and with weak upper-level troughing overhead. A similar pattern of scattered showers should continue Friday night through Saturday morning. By Saturday afternoon, showers will transition to steadier precipitation over the Olympics, central and north Cascades as warm frontal precipitation associated with an atmospheric river begins to shift into the region.
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
Thursday
Night
Cloudy with light to occasionally moderate rain and snow showers. Strong ridgeline winds.
Friday
Cloudy with light scattered showers.
Thursday
Night
Cloudy with moderate rain and snow showers. Strong ridgeline winds.
Friday
Cloudy with light to occasionally moderate showers.
Thursday
Night
Cloudy with moderate rain and snow showers. Strong ridgeline winds.
Friday
Cloudy with light to occasionally moderate showers.
Thursday
Night
Cloudy with moderate rain and snow showers. Strong ridgeline winds.
Friday
Mostly cloudy with scattered light to occasionally moderate showers. Strong ridgeline winds decreasing in the afternoon.
Thursday
Night
Cloudy with moderate rain and snow showers. Strong ridgeline winds.
Friday
Cloudy with scattered light to occasionally moderate showers. Strong ridgeline and Pass level westerly winds decreasing in the afternoon.
Thursday
Night
Cloudy with moderate rain and snow showers. Strong ridgeline winds.
Friday
Cloudy with scattered light to occasionally moderate showers. Strong ridgeline and Pass level westerly winds decreasing in the afternoon.
Thursday
Night
Cloudy with light to occasionally moderate rain and snow showers. Strong ridgeline winds.
Friday
Cloudy with scattered light showers. Strong ridgeline winds decreasing in the afternoon.
Thursday
Night
Cloudy with light to occasionally moderate rain and snow showers. Strong ridgeline winds.
Friday
Mostly cloudy with scattered light showers. Strong ridgeline winds decreasing in the afternoon.
Thursday
Night
Cloudy with light to occasionally moderate rain and snow showers. Strong ridgeline winds.
Friday
Mostly cloudy with scattered light showers. Strong ridgeline winds decreasing in the afternoon.
Thursday
Night
Cloudy with moderate rain and snow showers. Strong ridgeline winds.
Friday
Mostly cloudy with scattered light to occasionally moderate showers. Strong ridgeline winds decreasing in the afternoon.
Issued: 1:59 PM PST Thursday, February 18, 2021
Precipitation (in)
Thursday Night
Friday
Friday Night
Saturday
4 pm - 4 am
4 am - 4 pm
4 pm - 4 am
4 am - 4 pm
Hurricane Ridge
0.50
LT 0.25
LT 0.10
LT 0.10
Mt Baker Ski Area
0.75
0.25 - 0.50
0.25
LT 0.10
Mt. Loop - Barlow Pass
0.75 -1.00
0.50
LT 0.25
LT 0.25
Stevens Pass
0.50 - 0.75
0.25
LT 0.25
LT 0.25
Snoqualmie Pass
0.75
0.25
0.25
0.25
Crystal Mt
0.25
LT 0.25
LT 0.10
LT 0.25
Paradise
0.50 - 0.75
0.25 - 0.50
LT 0.25
LT 0.25
White Pass
0.50
0.25
LT 0.10
LT 0.25
Washington Pass
0.25 - 0.50
LT 0.25
LT 0.10
LT 0.10
Mission Ridge
LT 0.25
LT 0.10
LT 0.10
LT 0.10
Salmon la Sac - Gallagher Head
0.25 - 0.50
LT 0.25
LT 0.25
LT 0.10
Tieton River - Darland Mt.
0.25 - 0.50
LT 0.10
LT 0.10
LT 0.10
Mt Hood Meadows
0.75 -1.00
LT 0.25
LT 0.25
LT 0.25
Timberline
1.00
0.25
0.25
LT 0.25
Hurricane Ridge
Precipitation (in)
Thursday Night
0.50
Friday
LT 0.25
Friday Night
LT 0.10
Saturday
LT 0.10
Mt Baker Ski Area
Precipitation (in)
Thursday Night
0.75
Friday
0.25 - 0.50
Friday Night
0.25
Saturday
LT 0.10
Mt. Loop - Barlow Pass
Precipitation (in)
Thursday Night
0.75 -1.00
Friday
0.50
Friday Night
LT 0.25
Saturday
LT 0.25
Stevens Pass
Precipitation (in)
Thursday Night
0.50 - 0.75
Friday
0.25
Friday Night
LT 0.25
Saturday
LT 0.25
Snoqualmie Pass
Precipitation (in)
Thursday Night
0.75
Friday
0.25
Friday Night
0.25
Saturday
0.25
Crystal Mt
Precipitation (in)
Thursday Night
0.25
Friday
LT 0.25
Friday Night
LT 0.10
Saturday
LT 0.25
Paradise
Precipitation (in)
Thursday Night
0.50 - 0.75
Friday
0.25 - 0.50
Friday Night
LT 0.25
Saturday
LT 0.25
White Pass
Precipitation (in)
Thursday Night
0.50
Friday
0.25
Friday Night
LT 0.10
Saturday
LT 0.25
Washington Pass
Precipitation (in)
Thursday Night
0.25 - 0.50
Friday
LT 0.25
Friday Night
LT 0.10
Saturday
LT 0.10
Mission Ridge
Precipitation (in)
Thursday Night
LT 0.25
Friday
LT 0.10
Friday Night
LT 0.10
Saturday
LT 0.10
Salmon la Sac - Gallagher Head
Precipitation (in)
Thursday Night
0.25 - 0.50
Friday
LT 0.25
Friday Night
LT 0.25
Saturday
LT 0.10
Tieton River - Darland Mt.
Precipitation (in)
Thursday Night
0.25 - 0.50
Friday
LT 0.10
Friday Night
LT 0.10
Saturday
LT 0.10
Mt Hood Meadows
Precipitation (in)
Thursday Night
0.75 -1.00
Friday
LT 0.25
Friday Night
LT 0.25
Saturday
LT 0.25
Timberline
Precipitation (in)
Thursday Night
1.00
Friday
0.25
Friday Night
0.25
Saturday
LT 0.25
Issued: 1:59 PM PST Thursday, February 18, 2021
Snow Level (ft)
Thursday
Evening*
Thursday
Night
Friday
Morning
Friday
Afternoon
Friday
Evening
Friday
Night
Saturday
Morning
Saturday
Afternoon
Olympics
3500'
2000'
2000'
3000'
2000'
1500'
2000'
2500'
West North
2000'
1500'
2000'
2500'
2000'
1500'
1500'
2000'
West Central
2000'
2500'
2500'
2500'
2000'
1500'
1500'
2000'
West South
3000'
3000'
3000'
3000'
2000'
1500'
2000'
2000'
Stevens Pass
1500'
2500'
2500'
2500'
2000'
1500'
1500'
2000'
Snoqualmie Pass
2000'
2500'
2500'
2500'
2000'
1500'
1500'
2000'
East North
1000'
2000'
2000'
3000'
2000'
1000'
1500'
1500'
East Central
1500'
2500'
3000'
3000'
2000'
1500'
1500'
2000'
East South
2000'
2500'
3000'
3000'
2000'
1500'
1500'
2000'
Mt. Hood
4000'
3500'
3000'
3500'
2500'
2000'
2000'
2500'
Olympics
Elevation
Thursday
Evening*
3500'
Thursday
Night
2000'
Friday
Morning
2000'
Friday
Afternoon
3000'
Friday
Evening
2000'
Friday
Night
1500'
Saturday
Morning
2000'
Saturday
Afternoon
2500'
West North
Elevation
Thursday
Evening*
2000'
Thursday
Night
1500'
Friday
Morning
2000'
Friday
Afternoon
2500'
Friday
Evening
2000'
Friday
Night
1500'
Saturday
Morning
1500'
Saturday
Afternoon
2000'
West Central
Elevation
Thursday
Evening*
2000'
Thursday
Night
2500'
Friday
Morning
2500'
Friday
Afternoon
2500'
Friday
Evening
2000'
Friday
Night
1500'
Saturday
Morning
1500'
Saturday
Afternoon
2000'
West South
Elevation
Thursday
Evening*
3000'
Thursday
Night
3000'
Friday
Morning
3000'
Friday
Afternoon
3000'
Friday
Evening
2000'
Friday
Night
1500'
Saturday
Morning
2000'
Saturday
Afternoon
2000'
Stevens Pass
Elevation
Thursday
Evening*
1500'
Thursday
Night
2500'
Friday
Morning
2500'
Friday
Afternoon
2500'
Friday
Evening
2000'
Friday
Night
1500'
Saturday
Morning
1500'
Saturday
Afternoon
2000'
Snoqualmie Pass
Elevation
Thursday
Evening*
2000'
Thursday
Night
2500'
Friday
Morning
2500'
Friday
Afternoon
2500'
Friday
Evening
2000'
Friday
Night
1500'
Saturday
Morning
1500'
Saturday
Afternoon
2000'
East North
Elevation
Thursday
Evening*
1000'
Thursday
Night
2000'
Friday
Morning
2000'
Friday
Afternoon
3000'
Friday
Evening
2000'
Friday
Night
1000'
Saturday
Morning
1500'
Saturday
Afternoon
1500'
East Central
Elevation
Thursday
Evening*
1500'
Thursday
Night
2500'
Friday
Morning
3000'
Friday
Afternoon
3000'
Friday
Evening
2000'
Friday
Night
1500'
Saturday
Morning
1500'
Saturday
Afternoon
2000'
East South
Elevation
Thursday
Evening*
2000'
Thursday
Night
2500'
Friday
Morning
3000'
Friday
Afternoon
3000'
Friday
Evening
2000'
Friday
Night
1500'
Saturday
Morning
1500'
Saturday
Afternoon
2000'
Mt. Hood
Elevation
Thursday
Evening*
4000'
Thursday
Night
3500'
Friday
Morning
3000'
Friday
Afternoon
3500'
Friday
Evening
2500'
Friday
Night
2000'
Saturday
Morning
2000'
Saturday
Afternoon
2500'
Issued: 1:59 PM PST Thursday, February 18, 2021
5000' Temperatures (°F)
Thursday
Night
Friday
Max / Min
Max / Min
Olympics
28 / 24
26 / 22
West North
26 / 24
25 / 22
West Central
26 / 22
25 / 23
West South
28 / 25
27 / 24
Stevens Pass
27 / 22
26 / 23
Snoqualmie Pass
27 / 22
25 / 23
East North
23 / 19
26 / 21
East Central
26 / 21
26 / 22
East South
27 / 24
28 / 22
Mt. Hood
30 / 28
29 / 24
Olympics
5000' Temperature Forecast (Max / Min)
Thursday
Night
28 / 24
Friday
26 / 22
West North
5000' Temperature Forecast (Max / Min)
Thursday
Night
26 / 24
Friday
25 / 22
West Central
5000' Temperature Forecast (Max / Min)
Thursday
Night
26 / 22
Friday
25 / 23
West South
5000' Temperature Forecast (Max / Min)
Thursday
Night
28 / 25
Friday
27 / 24
Stevens Pass
5000' Temperature Forecast (Max / Min)
Thursday
Night
27 / 22
Friday
26 / 23
Snoqualmie Pass
5000' Temperature Forecast (Max / Min)
Thursday
Night
27 / 22
Friday
25 / 23
East North
5000' Temperature Forecast (Max / Min)
Thursday
Night
23 / 19
Friday
26 / 21
East Central
5000' Temperature Forecast (Max / Min)
Thursday
Night
26 / 21
Friday
26 / 22
East South
5000' Temperature Forecast (Max / Min)
Thursday
Night
27 / 24
Friday
28 / 22
Mt. Hood
5000' Temperature Forecast (Max / Min)
Thursday
Night
30 / 28
Friday
29 / 24
Issued: 1:59 PM PST Thursday, February 18, 2021
Ridgeline Winds (mph)
Thursday
Evening
Thursday
Night
Friday
Morning
Friday
Afternoon
Olympics
W 15-25
W 20-30
W 15-25
SW 10-20
West North
S 15-25
W 15-25
WSW 10-20
SW 5-15
West Central
S 15-25
W 20-30
W 15-25
WSW 10-20
West South
WSW 20-30
W 20-30
W 20-30
SW 10-20
Stevens Pass
SSE 10-20
W 20-30
WSW 15-25
WSW 10-20
Snoqualmie Pass
SSE 10-20
WSW 25-35
WSW 20-30
WSW 15-25
East North
SSW 15-25
W 20-30
W 15-25
W 10-20
East Central
S 15-25
W 30-40
W 25-35
W 15-25
East South
S 15-25
W 20-30
W 20-30
W 10-20
Mt. Hood
W 20-30
WSW 25-35
W 25-35
W 15-25
Olympics
Ridgeline Winds (mph)
Thursday
Evening
W
15-25
Thursday
Night
W
20-30
Friday
Morning
W
15-25
Friday
Afternoon
SW
10-20
West North
Ridgeline Winds (mph)
Thursday
Evening
S
15-25
Thursday
Night
W
15-25
Friday
Morning
WSW
10-20
Friday
Afternoon
SW
5-15
West Central
Ridgeline Winds (mph)
Thursday
Evening
S
15-25
Thursday
Night
W
20-30
Friday
Morning
W
15-25
Friday
Afternoon
WSW
10-20
West South
Ridgeline Winds (mph)
Thursday
Evening
WSW
20-30
Thursday
Night
W
20-30
Friday
Morning
W
20-30
Friday
Afternoon
SW
10-20
Stevens Pass
Ridgeline Winds (mph)
Thursday
Evening
SSE
10-20
Thursday
Night
W
20-30
Friday
Morning
WSW
15-25
Friday
Afternoon
WSW
10-20
Snoqualmie Pass
Ridgeline Winds (mph)
Thursday
Evening
SSE
10-20
Thursday
Night
WSW
25-35
Friday
Morning
WSW
20-30
Friday
Afternoon
WSW
15-25
East North
Ridgeline Winds (mph)
Thursday
Evening
SSW
15-25
Thursday
Night
W
20-30
Friday
Morning
W
15-25
Friday
Afternoon
W
10-20
East Central
Ridgeline Winds (mph)
Thursday
Evening
S
15-25
Thursday
Night
W
30-40
Friday
Morning
W
25-35
Friday
Afternoon
W
15-25
East South
Ridgeline Winds (mph)
Thursday
Evening
S
15-25
Thursday
Night
W
20-30
Friday
Morning
W
20-30
Friday
Afternoon
W
10-20
Mt. Hood
Ridgeline Winds (mph)
Thursday
Evening
W
20-30
Thursday
Night
WSW
25-35
Friday
Morning
W
25-35
Friday
Afternoon
W
15-25
Issued: 1:59 PM PST Thursday, February 18, 2021
Extended Weather Synopsis
We'll be on the warm side of the jet stream to start off this event, with the jet aimed into central British Columbia on Saturday night. Forecast models are in good agreement that a more significant wave of warm frontal moisture will drape over the area, stretching as far south as Mt Hood on Sunday. Snow levels should begin their slow but steady climb late Saturday night through Monday, likely settling somewhere around 5000-6000' on Monday. Several inches of water will likely accumulate over this period, heaviest over the west slopes of the Washington Cascades. Ensemble forecasts suggest that between Saturday night and Monday we are talking about 2-5 inches of water smeared across the PNW mountains.
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).