Who’s ready for a blast of cold air?

TUCSON –  With only a few days remaining in November, it seems likely that the month will go into the record books as slightly cooler than average.

October was also cooler than average. The last time Tucson strung together consecutive months with below average temperatures was November 2015 – January 2016. It’s a tight race but with a big pattern change arriving the last day of the month, odds favor another below average.

High pressure will result in mostly sunny and warm conditions Wednesday as highs warm well above average into the mid 70s. Thursday begins warm but then we track a cold front barreling down from the north. This front will pick up our winds and give us the best rain chance we’ve seen in almost a month. Most of our forecast tools indicate light rain – up to a 1/4″ with 1-3″ of snow for Mt. Lemmon. 

Rain is likely early Friday morning and highs will top off only into the low 60s. This cooler air mass will stick around through the entire weekend and another shot of light rain is possible through Monday. Sunday through Tuesday look very cold as temperatures struggle to get out of the mid-to-upper 50s. 

Snow levels will come crashing to 4500′ early Sunday morning, and some of the higher towns in the region could pick up a dusting of snow. 

The Climate Prediction Center keeps well below average temperatures around for much of next week as well. 

So giddy up Rudolph, it’s beginning to look – and feel – a lot like Christmas. 

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It WILL Snow in Portland

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!