September 9, 2011
It’s been quite a year! And now that we are in the waning days of summer, you should enjoy the warm weather because…well…let me break the news to you: winter is coming soon!
Every year for the last 20 I have issued a fall-winter “climate” forecast at this time. I don’t predict day-to-day conditions (“weather”) but rather overall averages (“climate”). Here’s what I predicted last year, and what happened:
What I said: gradually cooling, but over all a relatively mild and dry month compared to average Septembers. A nice “late summer” month.
What happened: correct, with the exception of a very wet day on the 19th, when 1.23 inches of rain fell. This caused the monthly total to be about an inch above average,
What I said: mild and relatively dry weather continues for most of the month. I expect beautiful fall weather for the most part.
What happened: October was quite mild, including two days in the 80s, but wetter than average, due largely to over two inches of rain on the 24th-25th.
What I said: A wet, windy, possibly wild winter. Lots of storms. Lots of rain. Lots of mountain snows. Possible Arctic outbreak. Possible low-elevation snow.
What happened: December was very wet, but the other months were a little on the dry side. “Wild” did not apply much.
What I said: drier and milder than this year’s spring, which was among the “wettest-coolest” we’ve seen. Not necessarily warmer and drier than normal, but much more so than this year.
What happened: another wet and cool spring, the second in a row. Late mountain snow, slow start to the growing season.
Summary: all in all , my predictions were pretty mediocre. I didn’t “bomb,” but I didn’t “nail it” either.
This year we are watching the tropical Pacific (as always) and see weak La Niña conditions continuing. During a weak La Niña, our winters tend to be wet but with near-average temperatures. The Climate Prediction Center (NOAA) is predicting the following for our area:
September-November: average temperatures, above-average precipitation.
December – February: below-average temperatures, above-average precipitation
March-May: below-average temperatures, average precipitation
My forecast is based largely on the tropical Pacific, but I also look at similar years in the past, since “history tends to repeat itself.” Here’s what I predict:
September: continued mild and mostly dry for most of the month.
October: dry, mild first half, cooler and wetter second half, but all told a warmer than average and relatively dry month.
November-February: a quiet November with considerable valley fog, with active weather beginning in December and continuing into February. Low elevation snow most likely in late January and early February.
March-April: drier than average but rather cool.
Enjoy the waning days of summer. I’m in no hurry for a “deep and dark December,” but I guess it’s inevitable!