July 2012: Hottest Month on Record for Contiguous U.S.

[donsutherland1]

From the NOAA:

The average temperature for the contiguous U.S. during July was 77.6°F, 3.3°F above the 20th century average, marking the hottest July and the hottest month on record for the nation. The previous warmest July for the nation was July 1936 when the average U.S. temperature was 77.4°F. The warm July temperatures contributed to a record-warm first seven months of the year and the warmest 12-month period the nation has experienced since recordkeeping began in 1895.

http://www.ncdc.noaa.gov/sotc/national/2012/7

[am19psu]

This is not an AGW thread.

[hm8]

This is not an AGW thread.

Nice preemptive strike.

[winterymix]

This is not an AGW thread.

Don S. for President

[MN Transplant]

Heck of a graph

[donsutherland1]

This is not an AGW thread.

Since one was dealing with a single month, not a climate period, I was unsure where to place this post. If it is better placed in the climate forum, please move it there.

Apologies if I put it in the wrong forum.

[am19psu]

Since one was dealing with a single month, not a climate period, I was unsure where to place this post. If it is better placed in the climate forum, please move it there.

Apologies if I put it in the wrong forum.

No, Don, you're fine, of course. There was an immediate AGW reply that I pinkied, so then I preemptively posted that this is not a thread to discuss AGW. If people want to discuss July 2012 in the context of AGW, it would be appropriate to do that in the Climate Change forum.

[donsutherland1]

No, Don, you're fine, of course. There was an immediate AGW reply that I pinkied, so then I preemptively posted that this is not a thread to discuss AGW. If people want to discuss July 2012 in the context of AGW, it would be appropriate to do that in the Climate Change forum.

Thanks. I wasn't sure what happened. I just wanted to post the monthly record here. I agree, if one wants to discuss the climate aspects, the climate change forum is a more appropriate venue for that discussion.

[icebreaker5221]

Well, from a non-AGW standpoint, there were a lot of factors contributing to the extreme heat. A persistent -PDO trough off the west coast (which kept the immediate west coast at or below normal btw) induced almost continuous downstream ridge development. An anomalously warm Atlantic in the middle of a +AMO era also kept the east coast / southeast warmer and ridge-ier than normal. Also, the persistent drought and accompanying low RH allowed the land surface and boundary layer to warm much higher during the day than it otherwise would have in the presence of normal moisture levels. Any other contributing factors?

[Vandy]

I think that's a pretty good summary. In the SW, the drier than normal land surface to the east encouraged the development of the strong persistent ridging we have seen. That in turn has stunted some of the monsoonal flow that would otherwise keep temperatures cooler in that part of the country.

[Mencken_Fan]

While summers in the Southeast are naturally hot, cities and towns directly on the Atlantic Coast might better be described as warm because we don't often experience blazing heat. But this summer? One could have camped out at the end of a fishing pier over the ocean and known something was "wrong."

The Carolina sea breeze typically has an easterly component; it may be SSE or just SE. But for much of this summer it's been S, SSW or even SW. While these may not intuitively sound like sea breeze directions, the geography of the Carolinas allow it; and the more the wind veers, the more mixed it is with hot continental air.

Therein lies the problem we experienced this summer. The hot continental air was so overpowering it quickly devoured the sea breeze air, forcing it to veer much sooner than normal. The net result was paltry breezes of hot air loaded with Atlantic humidity. Heat indexes shot through the roof. 100F at the coast will blow your mind.

July 2012 in Wilmington, N.C. was the hottest month ever recorded (local records go back to 1871.) Mean temperature for July was 84.7F a departure of +4.1F and rainfall was 2.31", a departure of -5.17". Twenty four days were at or above 90F.

Thank goodness this regime has come to an end. August is acting fairly normal; and compared to July it seems almost chilly!

[Roger Smith]

Hotter everywhere but Steele, ND (122 F in July 1936) and perhaps the rest of the northern plains states ... despite three whacks at the ball, the modern hot regime has failed to dethrone 1936 from notable all-time records in many parts of the north-central U.S. (and southern Canada). Of course, those are extremes, not averages. But my assessment is that July 2012 was like an almost-July-1936 with bigger urban heat islands and the somewhat undefined factor of greenhouse gas increases, which I believe have impacted mainly on overnight lows in summer temperatures.