Turning Colder Next Week

It now appears increasingly likely that the Pacific Northwest will see the arrival of an arctic air mass early next week. Computer guidance is now coming into better agreement with the evolution of cold arctic air that is forecast to slide into the Pacific Northwest from Canada. Snow levels will already be quite low over the weekend before the coldest air arrives. The timing of this change to much colder weather would also coincide with the heavily traveled holiday week. It is still to early to tell exactly how much, if any, low elevation snow will accompany this system, but this will surely be the coldest air mass to invade the Pacific Northwest since December of 2009. In fact, some of the most recent data suggests that daytime highs could be even colder yet, with high temperatures struggling to get above freezing in Portland and Seattle. If these "colder" model solutions were to verify, this would be the first time that Portland has experienced three back-to-back-to-back arctic outbreaks in 25 years that resulted in the high temperature at the Portland International Airport being held to 32 degrees or below. Again, those are the coldest model solutions. One has to go back to the winter of 1983/84, 1984/85 and 1985/86 to find three consecutive winters where Portland recorded high temperatures at or below 32 degrees for daytime highs at the airport."