A convergence zone and post-frontal showers will continue to pepper the west slopes of the Cascades and Mt Hood through about mid-day. The convergence zone is currently dropping south from Snohomish county into King county and bringing some locally moderate to even heavy snow showers to portions of Hwy 2 and I-90. Moderate to strong westerly winds will also continue through about mid-day, with the strongest winds reserved for the Mt Hood area and east-central Cascades. Areas directly downwind of the convergence zone along the east slopes of the Cascades will pick up a few inches this morning as well.
After a showery morning, we can expect showers to be lighter and more scattered to even isolated Wednesday afternoon. Upper level ridging building offshore will help trap low level moisture, so expect some sunbreaks but not full bluebird skies for areas near and west of the Cascade crest. Sunny skies will be widespread further east of the crest.
High pressure will be in control for the next few days. We can expect some passing high clouds tonight and Thursday, areas of low level patchy fog tonight, along with a fair amount of sunshine. Offshore flow and easterly gradients will increase during the day on Thursday, with winds becoming moderate in some areas. Freezing levels will warm to 4000-5000' on Thursday.
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
Wednesday
Mostly cloudy with scattered light snow showers. Sunbreaks throughout the day.
Wednesday
Night
Partly to mostly clear with periods of high clouds. Chance of light snow showers early in the evening.
Wednesday
Mostly cloudy with light snow showers this morning. Showers becoming scattered this afternoon. Sunbreaks possible throughout the day.
Wednesday
Night
Partly to mostly clear with periods of high clouds. Chance of light snow showers early in the evening.
Wednesday
Cloudy with light to occasionally moderate snow showers through mid-day. Mostly cloudy with sunbreaks and scattered light snow showers in the afternoon.
Wednesday
Night
Partly to mostly clear with periods of high clouds. Chance of light snow showers early in the evening.
Wednesday
Cloudy with light to occasionally moderate snow showers through mid-day. Mostly cloudy with sunbreaks and scattered light snow showers in the afternoon.
Wednesday
Night
Partly to mostly clear with periods of high clouds. Chance of light snow showers early in the evening.
Wednesday
Cloudy with light to occasionally moderate snow showers through mid-day. Mostly cloudy with sunbreaks and scattered light snow showers in the afternoon. Moderate west winds at Pass and ridgeline becoming light to moderate in the afternoon.
Wednesday
Night
Partly to mostly clear with periods of high clouds. Patchy valley fog. Chance of light snow showers early in the evening. Light west winds becoming light east overnight both at Pass level and ridgeline.
Wednesday
Cloudy with light to occasionally moderate to heavy snow showers through mid-day. Mostly cloudy with sunbreaks and scattered light snow showers in the afternoon. Moderate to strong west winds at Pass and ridgeline becoming light to moderate in the afternoon.
Wednesday
Night
Partly to mostly clear with periods of high clouds. Patchy valley fog. Chance of light snow showers early in the evening. Light west winds becoming light east overnight both at Pass level and ridgeline.
Wednesday
Mostly cloudy with light snow showers near the Cascade crest. Mostly sunny with moderate ridgeline winds further east of the Cascade crest.
Wednesday
Night
Mostly clear. Periods of high clouds. Patchy valley fog.
Wednesday
Mostly cloudy with light to occasionally moderate snow showers near the Cascade crest this morning, then showers becoming isolated this afternoon. Mostly sunny with moderate to strong ridgeline winds further east of the Cascade crest.
Wednesday
Night
Mostly clear. Periods of high clouds. Patchy valley fog.
Wednesday
Mostly cloudy with light snow showers near the Cascade crest. Mostly sunny with moderate ridgeline winds further east of the Cascade crest.
Wednesday
Night
Mostly clear. Periods of high clouds. Patchy valley fog.
Wednesday
Mostly cloudy with light to occasionally moderate snow showers this morning. Partly to mostly sunny this afternoon with scattered snow showers. More sun east-side of the mountain. Strong ridgeline decreasing this afternoon.
Wednesday
Night
Mostly clear. Periods of high clouds. Patchy valley fog.
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).