Last week there was a noticeable change in our weather. After recording only three days in the 70s over the previous 48 days, since last Thursday our high temperatures have been frequently in the 70s. Plus, on this upcoming Thursday and Friday, one (or both) of those two days may be only the second time this summer with a high in the 60s.
Is this a permanent change? My strong suspicion is yes. A major strong in the Arctic last week along with some subtle other changes in the flow pattern over the Northern Hemisphere has probably, at least in our region, put an end to the persistent heat of the past two months.
Back in 2006, our last warm summer, after recording 15 days with a high in the 90s (including two above 100) through July, the rest of that summer the temperature remained below 90 degrees. This month has the potential to be the first below average month in over a year and it would not surprise me if our autumn started cooler than average as well.
It does not mean there will not be anymore warm days, just that normal or slightly below normal temperatures look to be the dominate temperatures for a while.
I understand the comparison to 2006, with July being very warm that year, but I’m actually seeing parallels to 2007, with the exception that July was quite a bit warmer this year. This is using data from NDAWN’s Grand Forks station.
Avg. Monthly Temps
May 2007 – 58.4
May 2012 – 58.9
June 2007 – 67.9
June 2012 – 67.6
July 2007 – 70.9
July 2012 – 74.6 (I realize this is quite a bit warmer)
Aug. 2007 – 65.0
Aug. 2012 – 67.3 so far, and potentially trending cooler
So after a warm May-June-July, August became (unexpectedly) cool. Coincidently, Summers 2007 and 2012 have the same calendar.
Just for comparison…
July 2006 – 71.7
July 2012 – 74.6
So even July 2006 was almost 3 full degrees cooler than this year.
As usual, I was making comparison with Fargo’s data. NDAWN’s data, especially, 75 miles away, can be quite different. Plus, atmospheric and oceanic conditions this year are similar to 2006, not so much with 2007. 2006, as well as 2000, 1952 and 1954 where some years I used for my summer forecast posted in May. Hope that helps.
One thing I forgot to factor in my comparison was precipitation, which 2006 was much drier than 2007.