The influence of a relatively weak west-coast high pressure to our south will keep more impactful storm systems to our north in the short-term. Temperatures are 5-10F warmer than at this time yesterday morning at many NWAC station and high elevation stations have warmed significantly further (a temperature increase of 25F at Camp Muir!). A weak warm front will bring decreasing periods of very light snow to parts of Washington today. That snow may transition to very light rain as snow levels rise Sunday afternoon up to 3500-4500 ft in the areas of north and central Washington where precipitation lingers. The east slopes of the Cascades should experience mild and partly sunny conditions with clouds banked to against and west of the Cascade Crest.
Sunday night, any lingering snow flurries or sprinkles should end early. Another warm front allows even milder air to move into the region west of the Cascade Crest. A switch to more southerly flow allows pass-level winds to switch easterly, sucking cooler air through the Cascade Passes and likely setting up a temperature inversion through the passes. A frontal system impacting British Columbia should keep mid-level clouds over much of Washington State.
On Monday, mild temperatures continue with 4500-7000 ft freezing levels expected. The system impacting British Columbia weakens as it approaches NW Washington State by late in the afternoon.
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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Sunday
Mostly cloudy.
Sunday
Night
Mostly cloudy.
Sunday
Decreasing periods of very light rain and snow.
Sunday
Night
Very light rain and snow showers possibly lingering into the early evening then mostly cloudy skies.
Sunday
Decreasing periods of very light rain and snow.
Sunday
Night
Very light rain and snow possibly lingering into the early evening then mostly cloudy skies.
Sunday
Decreasing periods of very light rain and snow.
Sunday
Night
Mostly cloudy.
Sunday
Decreasing periods of very light rain and snow. Light W wind at the Pass.
Sunday
Night
Mostly cloudy. Variable wind switching light E at the Pass.
Sunday
Decreasing periods of very light rain and snow. Light W wind at the Pass.
Sunday
Night
Mostly cloudy. Variable wind switching light E at the Pass.
Sunday
Periods of very light rain and snow possible near the Cascade Crest with partly cloudy skies further east.
Sunday
Night
Mostly cloudy.
Sunday
Periods of very light rain and snow possible near the Cascade Crest with partly cloudy skies further east.
Sunday
Night
Mostly cloudy.
Sunday
Partly cloudy with a chance of sprinkles or flurries near the Cascade Crest.
Sunday
Night
Partly cloudy.
Sunday
Partly to mostly sunny with broken low clouds possible below 6000 ft.
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).