It seems like Portland is always on the bubble when it come to snow. We have so many near hits but so few home-runs. I am about 100% sure that snow will fall in the lowest elevations of downtown Portland and the airport.
We, Meteorologists, use a lot of tools to predict the weather. Current analysis, experience and serious computer models. Let’s review the models.
The NAM is probably our best short range (out to 84 hours) model. It shows plenty of cold air and enough moisture to drop snow to the valley floor.
The GFS is a longer range model and it agrees completely with the NAM
The Canadian and European models are also used (the EURO more frequently) and they are actually even colder than our “domestic” models.
I could really geek out even more and go into more detail but here’s my assurance. At some point in time from Sunday-Tuesday if you live in the City of Portland you will see snow. In my two years of forecasting in the City of Portland, this is the first time I’ve been so convinced.
I think the limiting factors, for the lowest elevations will be some onshore flow, the rain shadow effect (where the Coast Range steals our moisture) and the fact that temperatures will mainly be above freezing, so not more than 1-2″ in the valley but with any elevation a good 2-4″ could stick.
Get ready for a major pattern change by Wednesday – mild weather should return with potentially heavy rains. There may be a narrow window where the cold air is in place that we could see some ice issues but more on that later.
Let it snow!