Mountain Weather Forecast

Weather Synopsis

An unusual track for a low pressure system brought heavy precipitation (almost 2" WE in 12 hrs) for the Olympics and north Cascades today along with rising snow levels. As the low tracked NE across the Strait of Juan de Fuca to the north Cascades so did the warm air, with rain pushing up to around 5000' for the northwest Cascades and above Hurricane Ridge. The Washington Pass - Methow Valley corridor picked up a quick 10-12" as colder air remained entrenched further east. The more northerly orientation of the axis of heaviest precipitation gave the central, south Washington Cascades and Mt Hood areas a mid-day respite from heavier precipitation in the mild and very windy warm sector.

The warmth and localized break in the precipitation is coming to an end as the radar fills in with a menacing shield of precipitation slowly tracking eastward. The front will pass through the Cascades around 4 pm with a rapid cool down this evening. Rain will change to snow through the early afternoon and evening hours. The Washington Pass and east-central Cascades will see snow levels peak around 5500' and 6500' early this evening respectively before cooling. 

After the frontal passage, strong W-NW winds will wring out moisture along the central and south Washington Cascades and Mt Hood tonight with drier and less windy conditions for the north Cascades.  A convergence zone in between Stevens and Snoqualmie Pass will likely produce heavier snowfall totals there. Look for snow levels to fall to at least 1000' after midnight as colder air filters into the region. Scattered showers may last until the morning for Stevens and Snoqualmie Passes, but strong upper-level ridging will quickly build offshore. Look for a sunnier forecast on the east slopes of the Cascades and the Olympics tomorrow. Trapped stratocumulus clouds along the west slopes of the Cascades and Mt Hood will make for a mixed bag of afternoon cloud cover on Tuesday.  

High pressure and dry conditions will stay with us through Wednesday. Freezing levels will start to climb for areas west of the Cascade Crest. Expect temperature inversions and increasing east winds in the Cascade Passes during the day Wednesday.