We're in day 4 of a 5-day atmospheric river (AR), which continues to deliver copious amounts of rain to the western slopes of the Washington Cascades, particularly from Paradise northward. Thursday continues the pattern, with moisture streaming into the region on WSW flow. The West North and West Central zones will likely pick up 0.75-2" of water every 12 hours through Friday. However, a cold front approaching from the NW will increase precipitation and intensify rainfall rates in these areas Thursday night through mid-afternoon on Friday. Mt Hood remains dry at the southern end of the thick band of clouds. Westerly winds across the region will be persistent and strong, especially at higher elevations and in the alpine.
Snow levels will hover between 7500'-9500' over the WA Cascades, rising through Thursday evening, and then gradually lowering. Unfortunately, the strong cold front won't arrive in time for temperatures to cool off during the day on Friday, so most areas will experience rain.
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
Thursday
Light rain and highest elevation snow.
Thursday
Night
Increasing moderate rain.
Thursday
Moderate to occasionally heavy rain and snow at the highest elevations. Increasing light to moderate ridgeline winds.
Thursday
Night
Increasing moderate to heavy rain and highest elevation snow. Light to moderate ridgeline winds.
Thursday
Heavy rain and highest elevation snow. Increasing light to moderate ridgeline winds.
Thursday
Night
Heavy rain and highest elevation snow. Increasing light to moderate ridgeline winds.
Thursday
Light rain and highest elevation snow (moderate to heavy at Paradise). Moderate ridgeline winds.
Thursday
Night
Light rain and highest elevation snow (moderate to heavy at Paradise). Moderate ridgeline winds.
Thursday
Moderate rain. Moderate ridgeline and mostly light W wind at the Pass.
Thursday
Night
Increasing moderate to heavy rain. Light to moderate ridgeline and light W wind at the Pass.
Thursday
Moderate rain. Moderate ridgeline and mostly light W wind at the Pass.
Thursday
Night
Increasing moderate to heavy rain. Moderate ridgeline and light-to-moderate W wind at the Pass.
Thursday
Light rain and highest elevation snow. Moderate ridgeline winds.
Thursday
Night
Increasing light to moderate rain and snow. Moderate ridgeline winds.
Thursday
Light rain and highest elevation snow. Moderate ridgeline winds.
Thursday
Night
Light to moderate rain and highest elevation snow. Moderate ridgeline winds.
Thursday
Light rain and highest elevation snow. Moderate ridgeline winds.
Thursday
Night
Light rain and highest elevation snow. Moderate ridgeline winds.
Thursday
Mostly sunny early, then high clouds. 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).