A ridge of high pressure off the PNW coastline provides a sunny day on Tuesday. Most NWAC stations started the day well below freezing with some low clouds banked up against the west slopes of the mountains. These clouds should dissipate as temperatures rebound during the day. Freezing levels should rise into the 4000-5000 ft range with increasing light westerly cross-barrier flow boosting temperatures slightly east of the Cascade Crest. High clouds arriving from the northwest ahead of the next system should bring some filtered sunshine across NW Washington state in the afternoon.
Increasing clouds lower and thicken in the evening with light snow developing for the Olympics and the west slopes of the Washington Cascades overnight. Ridgeline winds increase into the light to moderate range.
Moderate rain and snow spread from NW to SE across the region on Monday Monday morning as the frontal system approaches. Moderate post-frontal showers continue for the west slopes of the Cascades during the afternoon. Convergence may develop in the central Cascades during the afternoon, locally enhancing rain/snowfall rates. While we expect mostly snowfall at 3000 ft, diurnal warming may limit snowfall accumulation at Snoqualmie Pass level. Ridgeline winds should be in the moderate range with strong gusts likely through mountain gaps and along 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
Use dropdown to select your zone
Tuesday
Mostly sunny in the morning with increasing high clouds. Clouds thickening late in the day.
Tuesday
Night
Cloudy with light rain and snow developing in the early morning hours.
Tuesday
Sunny in the morning with valley fog dissipating at low elevations. Increasing high cloud in the afternoon, thickening late in the day.
Tuesday
Night
Cloudy in the evening with increasing light rain and snow overnight.
Tuesday
Mostly sunny in the morning with valley fog dissipating at low elevations. Increasing high cloud in the afternoon.
Tuesday
Night
Cloudy in the evening with increasing light rain and snow overnight.
Tuesday
Mostly sunny skies with valley fog dissipating at low elevations in the morning hours. High clouds increasing late in the day.
Tuesday
Night
Cloudy in the evening with very light rain and snow possible overnight.
Tuesday
Mostly sunny skies with valley fog dissipating at low elevations in the morning hours. High clouds increasing late in the day.
Tuesday
Night
Cloudy in the evening with increasing very light rain and snow overnight.
Tuesday
Mostly sunny skies with valley fog dissipating at low elevations in the morning hours. High clouds increasing late in the day.
Tuesday
Night
Cloudy in the evening with increasing very light rain and snow overnight.
Tuesday
Mostly sunny skies with high clouds increasing late in the day.
Tuesday
Night
Cloudy with very light snow possibly developing after midnight.
Tuesday
Mostly sunny skies.
Tuesday
Night
Cloudy with very light snow possibly developing after midnight.
Tuesday
Mostly sunny skies.
Tuesday
Night
Cloudy with a chance of snow flurries after midnight.
Tuesday
Mostly sunny skies.
Tuesday
Night
Cloudy with a chance of snow flurries after midnight.
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).