A weak frontal system continues to slowly trudge southward this morning from it's current position over southern B.C. We'll see light rain and snow develop during the morning hours for the Olympics and the northern Cascades. The leading edge of the precipitation will barely nudge southward this afternoon into the central Cascades. In a similar theme to the precipitation forecast, overcast skies will also spread southward this morning. Even if your area doesn't see precipitation during the day, cloud ceilings are likely to lower in the afternoon. Moderate S-SW ridgeline winds will develop over the area in the afternoon, with stronger winds already ramping up over the Olympics and Mt Baker area this morning. Areas south of the frontal boundary will remain mild today.
The upper low currently positioned offshore will pull south and away from the PNW Thursday night. This will stand up the frontal system, making it more north-south oriented and further weaken it. Light showers will not amount to much overnight, but snow levels will come down into the 4000-6000' range. On Friday, the low will drift closer to the California coast, opening up and directing southerly flow aloft over the area. We should see scattered showers closer to the low for Mt Hood, and perhaps some isolated light showers over the WA Cascades. Cloudy skies may start to thin in the afternoon for areas furthest from the low, near and north of Hwy 2 and the Olympics. Freezling levels will rebound back into the 6000-7000' range by the 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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Thursday
Cloudy with light rain and snow developing this morning. More moderate precipitation S and SW slopes of the Olymipcs. Moderate ridgeline winds.
Thursday
Night
Cloudy with scattered light rain and snow showers. Moderate ridgeline winds easing after midnight.
Thursday
Cloudy with light rain and snow developing this morning, becoming light to occasionally moderate this afternoon. Moderate ridgeline winds becoming occasionally strong this afternoon.
Thursday
Night
Cloudy with scattered light rain and snow showers. Moderate to strong ridgeline winds easing after midnight.
Thursday
Cloudy with light rain and snow developing later this morning. Moderate ridgeline winds.
Thursday
Night
Cloudy with scattered light rain and snow showers. Moderate ridgeline winds easing after midnight.
Thursday
Cloudy. A chance of light rain and snow this afternoon. Moderate ridgeline winds.
Thursday
Night
Cloudy with scattered light rain and snow showers. Moderate ridgeline winds.
Thursday
Cloudy with light rain and snow developing in the afternoon. Light to moderate SW-W ridgeline and Pass level winds increasing in the afternoon.
Thursday
Night
Cloudy with scattered light rain and snow showers. Moderate SW-W ridgeline and Pass level winds easing after midnight.
Thursday
Cloudy with light rain and snow developing in the afternoon. Light to moderate SW-W ridgeline and Pass level winds increasing in the afternoon.
Thursday
Night
Cloudy with scattered light rain and snow showers. Moderate SW-W ridgeline and Pass level winds easing after midnight.
Thursday
Cloudy with light rain and snow developing later this morning. Moderate ridgeline winds.
Thursday
Night
Cloudy with scattered light rain and snow showers.
Thursday
Cloudy. Moderate ridgeline winds.
Thursday
Night
Cloudy with scattered light rain and snow showers. Moderate ridgeline winds easing after midnight.
Thursday
Mostly cloudy in the morning with mid and high clouds, then becoming overcast mid-day. Moderate ridgeline winds developing in the afternoon.
Thursday
Night
Cloudy with scattered light rain and snow showers. Moderate ridgeline winds easing after midnight.
Thursday
Mostly cloudy in the morning with mid and high clouds, then becoming overcast mid-day. Moderate ridgeline winds developing in the afternoon.
Thursday
Night
Cloudy with scattered light rain and snow showers. 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).