We're getting close but the atmospheric river that has dumped 5-10" of water over the last few days (mostly in liquid form) is not quite done with us yet. The axis of precipitation is oriented SW-NE this morning and afflicting both sides of the Cascades. The moisture tap will continue to weaken during the day and slowly shift eastward. W-SW Winds will be strongest along the southern and eastern peripheries of the frontal boundary, affecting Mt Hood and the mountains along the east slopes of the Cascades near and south of I-90. Snow levels will slowly lower today, beginning in the NW Cascades, as cooler air filters in behind the frontal boundary.
A new but much weaker surface low will spin up offshore Wednesday night and cross the Cascades on Thursday. This won't be a big weather event yet there's a lot of uncertainty with the timing and track. For now, we can expect light precipitation totals across the region, perhaps slightly heavier down near Mt Hood. Snow levels will continue to fall through Thursday afternoon, settling into the 3500-4000' range. As the low passes to the east on Thursday afternoon, there's the potential for a burst of moderate westerly winds from Stevens Pass and south to Mt Hood.
Weather Forecast
Olympics
West North
West Central
West South
Stevens Pass
Snoqualmie Pass
East North
East Central
East South
Mt. Hood
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Wednesday
Cloudy with a chance of light rain or snow.
Wednesday
Night
Mostly cloudy with a chance of light rain and snow showers.
Wednesday
Light rain or snow this morning, then cloudy.
Wednesday
Night
Mostly cloudy with a chance of light rain and snow showers.
Wednesday
Light to occasionally moderate rain or snow this morning, tapering off in the afternoon.
Wednesday
Night
Cloudy with light rain and snow showers.
Wednesday
Light to occasionally moderate rain or snow this morning, becoming lighter in the afternoon.
Wednesday
Night
Cloudy with light rain and snow showers.
Wednesday
Light to occasionally moderate rain or snow this morning, tapering off in the afternoon.
Wednesday
Night
Cloudy with light rain and snow showers.
Wednesday
Light to occasionally moderate rain or snow this morning, becoming lighter in the afternoon.
Wednesday
Night
Cloudy with light rain and snow showers.
Wednesday
Light to occasionally moderate rain or snow this morning, tapering off in the afternoon.
Wednesday
Night
Mostly cloudy with a chance of light rain and snow showers.
Wednesday
Light to occasionally moderate rain or snow this morning, becoming lighter in the afternoon.
Wednesday
Night
Mostly cloudy with a chance of light rain and snow showers.
Wednesday
Light to occasionally moderate rain or snow this morning, becoming lighter in the afternoon.
Wednesday
Night
Mostly cloudy with a chance of light rain and snow showers.
Wednesday
Light to occasionally moderate rain or snow. Moderate to strong ridgeline winds.
Wednesday
Night
Cloudy with light rain and snow. Moderate to strong ridgeline winds.
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).