Last Warm Day of the Year in Central Oregon?

Hope you enjoyed yesterday, because it might have been our last warm day (70+) of the year. After a frosty start, we topped out at a pleasantly warm 77 degrees, six degrees above average.

Couldn’t Crack 80
The National Weather Service forecasted a high of 82, as did weather.com. Neither forecasted a low near freezing (we hit 32.7 but had frost), so perhaps that cold start prevented us from hitting the magic 80 degree mark.

The Bend Airport’s high reached 84 after a comparatively balmy low of 42, so my reasoning holds there. What about Redmond? The airport soared to 85 after a chilly 33 degree start, an impressive 52 degree diurnal temperature swing. Hmmn…my theory doesn’t look so good after digesting those numbers. Perhaps Sisters had a bit of an inversion (cold air near the ground/warmer air above it; not the usual atmospheric setup!) that prevented the air mass from reaching its maximum temperature. More research may be needed.

golden quaking aspens

Central Oregon aspens will soon look like this. Glorious!

Next Two Weeks Look Very Autumnal
So why was yesterday probably our last 70 degree day until, I don’t know, April 2018? There are several reasons, but the most important are the rapidly decreasing sun angle and length of day. Even a week after the autumnal equinox, each day we’re still losing more than three minutes of daylight. Add that to an increasingly lower sun angle and it makes it harder to hit 70.

Oh, and soon storms will start rolling in from the Pacific, and while October storms don’t pack the meteorological wallop that December ones do, clouds and cool Pacific air tend to keep high temps in the 50s and low 60s.

The long-range forecasts are not on our side either. The Climate Prediction Center and weather.com call for 50s and 60s for the next two weeks. Adding all of these ingredients together, past mid-October it’s tough for Central Oregon to squeeze out another sparkling 70 degree day.

Let’s hope the forecasts are wrong and we can eke out at least one more 70 degree day before Old Man Winter takes up residence in Central Oregon for several months.