Most mountain locations are waking up to temperatures in the 20s and low 30s, with Washington Pass the outlier in the mid-teens. A band of moisture associated with a trough off the California coast has lifted a band of light rain and snow over the Mt Hood area. This band should linger around this area much of the day, spreading some cloud cover as far north as Mt St Helens and Mt Adams. The next more significant system, a closed low over the Gulf of Alaska, is increasing high clouds over the remainder of Washington State as the upper low drops south off the British Columbia Coastline. In most areas, ridgeline winds are light; areas favored by southerly flow (Baker) and easterly flow (the mountain gaps and areas near the Cascade Crest) can expect moderate ridgeline winds at times.
As the frontal system approaches Tuesday night, expect increasing periods of light rain and snow, initially for the southern Cascade volcanoes Tuesday evening, then spreading throughout much of Washington State overnight. Easterly flow remains mostly light while southerly winds increase, potentially bringing more sustained moderate winds to the Baker area.
On Wednesday, a frontal rain band pivots over the area, bringing increasing amounts of moderate rain and snow, with precipitation favoring southern Washington. SW ridgeline winds will increase throughout the day, along with E flow. This will keep snow levels around 3000-4000 ft east of the Cascade Cres,t while snow levels will be slightly higher to the West. The E flow will also allow for spillover onto the east slopes of the Cascades.
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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Tuesday
Filtered sunshine.
Tuesday
Night
Periods of light rain and snow develop in the early morning hours,
Tuesday
Filtered sunshine. Moderate ridgeline winds at times.
Tuesday
Night
Cloudy with moderate rain or snow developing in the early morning hours. Moderate ridgeline winds.
Tuesday
Filtered sunshine. Moderate ridgeline winds at times near the Cascade Crest.
Tuesday
Night
Cloudy with periods of light rain or snow developing overnight. Moderate ridgeline winds at times near the Cascade Crest.
Tuesday
Filtered sunshine. Cloudy conditions possible in the south. Moderate ridgeline winds at times near the Cascade Crest.
Tuesday
Night
A few light rain or snow showers in the evening, then increasing light rain or snow overnight. Moderate ridgeline winds near the Cascade Crest.
Tuesday
Filtered sunshine. Light to occasionally moderate ridgeline and E wind at the Pass.
Tuesday
Night
Cloudy in the evening. Periods of light rain or snow develop overnight. Light to occasionally moderate ridgeline and E wind at the Pass.
Tuesday
Filtered sunshine. Light to moderate ridgeline and E wind at the Pass.
Tuesday
Night
Cloudy in the evening. Periods of light rain or snow develop overnight. Light to moderate ridgeline and E wind at the Pass.
Tuesday
Filtered sunshine.
Tuesday
Night
High clouds lower and thicken.
Tuesday
Filtered sunshine.
Tuesday
Night
Periods of light rain or snow develop overnight.
Tuesday
Filtered sunshine, with cloudy conditions possible in the south.
Tuesday
Night
A few light rain or snow showers in the evening, then increasing light rain or snow overnight.
Tuesday
Light rain and snow at times.
Tuesday
Night
A few light rain or snow showers in the evening, then increasing light rain or snow overnight. Increasing moderate 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).