Another National Hot Summer With Another Central U.S. "Warming Hole"

Long range predictions issued in the spring for what the nation's summer would be like turned out to be pretty darned accurate.  

Those forecasts said the West and East coasts had the best chances of a hot summer this year, while there was a somewhat lesser chance of that happening in the central and northern Plains.  

Here was the forecast for chances of above or
below normal temperatures for this past summer
This forecast was issued on May 16. 

That's just what happened.

As the Washington Post tells us:

"Many dozens of cities in the West, Northeast and Gulf Coast posted their hottest summer on record (as measured by average temperature for the three-month period). California and Arizona had the most locations with record hot summers."

For the record, here in Vermont, Burlington logged its third hottest summer.

Though the northern and central Plains and Midwest had some heat waves over the summer, it wasn't really a blockbuster one for heat.

Which follows a well defined trend. Summer temperatures in much of the middle third of the nation have not been warming like the East and West coasts. It's as if climate change is vacationing away from the Midwest during the summer. 

A recent paper in the Journal of the American Meteorological Society helps explain what's going on. Ironically, the seeming lack of climate-related summer warming in the Midwest is largely the fault of (drum roll......) climate change. 

This is how summer actually turned out. The deeper the
red, the warmer relative to average it was. Blue areas
were slightly cooler than average. This is pretty
darn close to that forecast from May 16.

The Plains have gotten wetter in the summer than in previous decades, according to the paper.  It's interesting that daytime highs in months like June, July and August in the Plains have not risen, but  overnight lows have.

Wetter, more humid days tend to suppress daytime temperatures in the summer, but such weather can keep nights warmer.   Writers of the paper note that average atmospheric pressure during the summer in the Plains has gone down, indicating the presence of more storm systems. 

Extra storm systems also pull down batches of cooler Canadian air as they pass through, contributing to that lack of warming.

 Fewer storms would have allowed air either move up from the south as heat waves, or just warm up under the strong sunshine of summer. 

Land use such as increased irrigation might also be contributing to the relative coolness in the Plains, but that doesn't seem to be the main factor.

And yes, climate change could well be contributing to the increased wetness in the Plains, so as usual with this type of thing, yes, a warming world might actually be cooling the the central U.S. in the summer.