Warm Summer To Persist?

Warm Summer to Continue the Remainder of the Season

Mid-Summer Update 7/15/10

William R Deedler, Weather Historian National Weather Service White Lake Mi

It’s been a fairly warm summer across Southeast Lower Michigan this year with temperatures averaging two to three degrees above normal for the first half of the summer (depending on location). While it’s been warm this summer, all locations (except Detroit) are not yet in the top 20 warmest summers list.  However, with the warmest part of the summer (climatologically speaking) on our doorstep (roughly mid July to early Aug), there is a decent chance these mid-summer averages may rise further and more locations could place.

Detroit, with its heat island influence, is the exception (thus far) by placing in the warmest summers list. With an average temperature of 72.8 into mid July, this places this summer in 18th place for warmest summer in Detroit. By the way, not too long ago back in 2006 that 72.8 degree temperature was the entire summer average. Detroit’s average or typical summertime temperature for approximately the first six weeks of the summer /Jun-Jul 15/ is about 70.2 degrees. Therefore, with a current average temperature of 72.8 degrees, so  far this summer’s temperature is running about 2.6 degrees above normal.

At Flint, the average temperature thus far for the first half of the summer is 70.5 degrees. Generally, up until mid July the temperature averages about 67.5 degrees at Flint and therefore, this summer so far has averaged 3.0 degrees above the normal.

In Saginaw, the summer temperature thus far is at 70.2 degrees and normally for the first six weeks of the summer, Saginaw averages about 68.0 and thus, it’s been 2.2 degrees above normal.

Rest of the Summer

If the temperatures were to average for the entire summer what they are as of mid July, overall Southeast Lower Michigan would average about 71.1 degrees for the summer. Normal for the entire region for a summer is about 69.5 and therefore, 1.6 above normal.  In my Outlook, I projected temperatures to average on the warmer side of normal up to +1.5 degrees. I discussed that the warmer summers in the later years of my analogues along with the recent warm spring was the trend to follow. Also, any other guidance presented in my Outlook was too cool for this summer

Weighing the intermediate and short term data a bit more heavily, look for our summer temperatures to average numerically /0.0 to +1.5 degrees/ which seems suitable given the data.

While initially the forecast was pointed well in the right direction, I feel magnitude of the departure should be a bit higher. Taking into account the strength of the warmth this summer, the prevailing 500 MB pattern (which has simulated well the later analogue years mean 500 MB pattern presented in the Outlook), I look for temperatures to average 1.5 to 2.2 above normal by summer's end. The rest of the original summer outlook (patterns and rainfall) remains unchanged.


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