A well-developed cutoff low should drift SE toward California today. An attached weak warm front has lifted north of the US-Canadian border with tapering rain and high elevation snow in the Mt. Baker area ending early this morning as the front continues to rotate to the NW. Light SSW ridgeline winds continue within the mostly cloudy warm sector over the region on Sunday. Light E flow through the mountain gaps should switch westerly later in the day.
In the late afternoon, an isolated shower or thunderstorm along the crest of the Cascade could become scattered Sunday night as an upper trough passing mostly north of the Canadian border brings showers to northern areas of the region.
Moisture wrapping around the low off the California coastline and with the trough passing through the region should peak on Monday. WSW winds should focus any convergence on the Mt. Baker area early in the day which could shift south toward the central Cascades by the afternoon. Snow levels gradually lower from around 7000 ft Sunday night to 5500-6000 ft by Monday 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. Mild.
Sunday
Night
Sunday
Very light rain early, then mostly cloudy. Mild.
Sunday
Night
Sunday
Mostly cloudy. Mild.
Sunday
Night
Sunday
Mostly cloudy. Mild.
Sunday
Night
Mostly cloudy. Mild.
Sunday
Mostly cloudy. Mild. Light E wind switching W at the Pass in the afternoon.
Sunday
Night
Mostly cloudy. Mild. Light W wind at the Pass.
Sunday
Mostly cloudy. Mild. Light E wind switching W at the Pass in the afternoon.
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).