Mountain Weather Forecast

Weather Synopsis

240PM Update: Adjusted Friday weather summary for all zones.  We're in for an active few days of weather as a series of frontal systems impact the region.  Currently this afternoon, a warm front is lifting across the northern Oregon and the south Washington Cascades, with some heavier than expected showers over the Olympics and northwest Cascades. These showers should peter out early this evening.

The warm frontal boundary roughly straddling the WA/OR border will be the main feature to watch with a secondary pulse of precipitation arriving overnight. This should bring moderate to heavy precipitation to the Mt Hood area with light to moderate precipitation over the south WA Cascades, with much lighter amounts further north. Cool easterly flow will drag cold air across the Passes, keeping snow levels at Pass level or below. The Mt Hood area will likely see a wintry mix of snow, rain, and freezing rain through the early morning hours before cooling and likely turning back to snow closer to Friday morning. Right now the Passes look like they'll stay all snow, Snoqualmie Pass will likely see some very wet snow at Pass level after the heaviest precipitation has lifted north on Friday. 

The warm front will lift northwards during the day on Friday, spreading moderate precipitation to the north Cascades in the afternoon and tapering in intensity for areas for further south. This will be a moderate snow producer with most areas in the Cascades receiving between 6-10", with slightly lower amounts for the Passes. All areas will see a slow warming trend, and look for a switch to rain at lower elevation trailheads for areas West of the crest. The Olympics will see localized heavy snow across the eastern slopes with 3500-4500' snow levels. Other highlights with this storm include moderate to strong S-SE ridgeline winds that ramp up tonight and last through much of Friday across the region. 

We'll see lighter showers become lighter Friday night into Saturday morning but the relative break in the action won't last long.  Another frontal system will move into the area on Saturday, spreading light precipitation into Oregon and parts of southern/central WA.