Since the weekend, light snow showers have been falling across the Pacific Northwest, extending to low elevations including the valley floor. On Tuesday, Portland experienced the heaviest precipitation yet, with morning snowfall accumulation of up to three inches.
The worst is yet to come, however. Weather radar shows a monumental, perhaps even historic winter storm to head in to the Northwest late Tuesday night through Wednesday. Anywhere from three to six inches of snow can be expected in the greater Portland area, with up to 18 inches around Seattle.
The storm will pass through Oregon and Washington into the Rocky Mountains (accumulation can be expected in cities such as Seattle, Olympia, Bellingham, Portland and Vancouver). However, by Wednesday, warm air will push into the region, eventually turning the snow into rain showers. Snow will stick above 500 feet, and mixed rain and snow showers below that elevation. Numerous traffic crashes have already been reported all around the region, but it is likely that the wintry weather will cease after Wednesday.