An upper-level trough keeps unsettled, though not particularly impressive weather in the picture during the day on Monday. The western slopes and the Olympics stay mostly cloudy with occasional filtered sunshine, while the eastern slopes and locations near the crest see some more partly cloudy skies with a bit more sunshine, especially in the morning. Expect passing snow showers in many mountain locations, especially on the west side and Mt Hood. As westerly winds increase through the afternoon, cloud cover should build and showery activity will become more widespread. A convergence zone sets up in the early evening and looks to target the Snoqualmie Pass area, perhaps extending towards the West Central and Stevens Pass as well, bringing locally heavier snow accumulations to those zones, while Mt Hood gets an even more solid wallop of snow overnight. Snow levels remain below all mountain trailheads.
Other than Mt. Hood, the mountains look to dry out overnight and through the day on Tuesday as a transient dirty ridge builds over Washington. It should be a pleasant day in the mountains. There could still be a stray shower or two, but only Mt Hood and perhaps Mt St Helens should receive impactful precipitation totals overnight and during the day. Even those locations dry later in the day as everywhere sees a relative break in the action before a series of storms make landfall on Wednesday 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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Monday
Partly to mostly cloudy skies with filtered sunshine and a chance of snow showers, especially in the afternoon. Light westerly winds increase to moderate and cloud cover increases in the afternoon.
Monday
Night
A chance of light snow showers as skies begin to clear overnight. Moderate westerly winds decrease to light.
Monday
Partly to mostly cloudy skies with filtered sunshine and occasional snow showers, especially in the afternoon. Light westerly winds increase to moderate.
Monday
Night
A chance of light snow showers as clouds partially recede overnight. Moderate westerly winds decrease a bit.
Monday
Mostly cloudy skies with occasional filtered sunshine and snow showers, especially in the afternoon. Light westerly winds increase to moderate.
Monday
Night
Snow showers, especially in the evening. Locally heavier accumulations are possible. Clouds recede some overnight. Moderate westerly winds.
Monday
Partly to mostly cloudy skies with filtered sunshine and occasional snow showers, especially in the afternoon. Light westerly winds increase to moderate.
Monday
Night
Snow showers give way to some partial clearing overnight. Moderate westerly winds.
Monday
Mostly cloudy skies with an occasional bit of filtered sunshine and occasional snow showers, especially in the afternoon. Light westerly winds increase to moderate.
Monday
Night
Snow showers, especially in the evening. Locally heavier accumulations are possible. Moderate westerly winds.
Monday
Mostly cloudy skies with an occasional bit of filtered sunshine and occasional snow showers, especially in the afternoon. Light westerly winds increase to moderate.
Monday
Night
Snow showers, and perhaps heavier snow for a few hours in the evening. Locally heavier accumulations are possible. Moderate westerly winds.
Monday
Partly to mostly cloudy skies with filtered sunshine and occasional snow showers, especially in the afternoon. Light westerly winds increase to moderate.
Monday
Night
Snow showers give way to some partial clearing overnight. Moderate westerly winds.
Monday
Partly to mostly cloudy skies with filtered sunshine and occasional snow showers, especially in the afternoon. Light westerly winds increase to moderate.
Monday
Night
Snow showers give way to some partial clearing overnight. Moderate westerly winds.
Monday
Partly to mostly cloudy skies with filtered sunshine and occasional snow showers, especially in the afternoon. Light westerly winds increase to moderate.
Monday
Night
Snow showers give way to some partial clearing overnight. Moderate westerly winds.
Monday
Partly to mostly cloudy skies with filtered sunshine and snow showers, especially in the afternoon. Moderate to strong westerly winds.
Monday
Night
Snow, heavy at times. Moderate to strong westerly 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).