Mountain Weather Forecast

Weather Synopsis

Moderate to strong offshore flow peaked Wednesday night but continued on Thursday as a very deep low pressure transited the offshore waters aining for British Columbia. The consistent southerly flow aloft has helped to erode the cold air pool east of the Cascades where temperatures at low elevations hover around the freezing mark. We've seen very significant downslope warming with these gusty winds for the west slopes of the Cascades, foothills, and lowlands. With moderated air to start with, some lowland locations reached a balmy 60F during the mid-day hours!

The general weather pattern is that deep lows move into an area about 1000 miles off the PNW coastline, then travel N or NE into British Columbia. The first such deep low exits due north with a band of showers circulating around the low bringing moderate to heavy precipitation late this afternoon and overnight for the Olympics and Mt. Baker areas. Most other areas will experience light precipitation. Southerly winds peak with the transiting upper trough Thursday evening and also expect an uptick in E winds at low levels along with upslope precipitation enhancement east of the Cascade Crest. Snow levels drop with the transiting upper trough from around 4000 ft to around 3000 ft for the west slopes of the Cascades.

Much of the region may temporarily dry out as the western US ridge expands slightly into our region. But, any drying will be short-lived as the second deep low moves into the offshore waters with a leading front spreading light to moderate precipitation throughout the region by the afternoon. The front arrives Friday evening with a round of moderate to occasionally strong southerly winds. The front lingers with periods of precipitation through Saturday.