After several days of wavering, computer weather models now show that much colder weather will likely strike the entire Pacific Northwest beginning early next week, says meteorologist Steve Pierce of Northwest Weather Consultants.
In a Thanksgiving Day press release, Pierce stated that snowfall levels will likely fall to very near the valley floor as a cold system from Alaska sweeps across the region on Monday. In the wake of the frontal passage, temperatures will fall further with a frigid east wind developing near the Portland metro area and the Columbia River gorge.
Pierce said daytime high temperatures will likely struggle to get above freezing most of next week, with overnight lows of 15 to 25 degrees on the west side of the Cascades and 5 to 10 across most of eastern Washington and Oregon. Modified arctic air will likely continue to spread across the region for the remainder of the week.
It is still uncertain how much moisture will be available once the cold air is in place. Pierce said some of the more trusted weather models predict a disturbance later next week that has the potential to bring snowfall to all elevations, followed by even colder air behind that system, lasting well into the weekend of December 7-9. However, Pierce said there is still plenty of time for adjustments to current modeling forecasts.