Recap of record-breaking heat this past July in the U.S. Possible new heat record for Asia observed

Although the final ranking of this past July will not be released by the NCDC until around August 7th, it would appear that the month will almost certainly rank in the top five warmest July’s on record since official records began in 1895 (and perhaps even in the top three). Here is a summary of some of the more notable records set so far this summer. In addition, I have included a brief message concerning a potential new heat record for the continent of Asia.

Although this map is specifically for July 5th, it represents the overall pattern that most of the country has been stuck with for almost the entire month of July 2012.

Warmest Single Month on Record (any month)

Preliminary data from the NCDC reports that 4,313 record daily highs, 293 monthly record highs, and 171 all-time record highs were observed this past July (among the approximately 5,500 various official weather sites across the nation). Many of these sites, however, have limited periods of record that do not extend back to the 1930s when the country’s greatest heat waves occurred.

The WU extremes U.S. database follows 298 significant sites in the country, all of which have long periods of record (almost all back to the 19th century) and represent a mosaic of evenly spaced geographic locations representing all the climate zones in the country. About 90% of the country’s population resides within a 50-mile radius of one of these sites. From this list the following cities recorded their single-warmest month on record:

The following cities from the WU extremes database have broken or tied their all-time absolute maximum temperatures on record (including this past June):

Comparing this July to July of 2011

Perhaps what is truly astonishing is that this July (2012) piggybacks upon the equally torrid summer (and July) of 2011. Although, back-to-back record-breaking hot summers are not unheard of (summers in the 1930s and 1950s come to mind) it is nevertheless disconcerting.

Here is a comparison of extremes reached in July 2012 versus July 2011. Also, to put this in context, is a comparison to July of 1936, still almost certainly the hottest July (and single month) in U.S. records. Again this list includes only the 298 cities in the WU database:

This table shows the number of cities (out of 298 in all) that recorded their respective single-warmest month on record and absolute maximum temperature on record for the June-July month timeframes in 2012, 2011, and 1936.

Honorable Mentions

Other major cities came VERY close to breaking their all-time warmest single month on record including Washington, D.C. (National Airport) with a July average of 84.0° just shy of the record 84.5° set last July (2011). The Dulles Airport location was also close with 80.6° vs. 81.0° in July 2011. Raleigh, North Carolina averaged 83.5°, shy of their record 84.1° set in August 2007. Chicago, Illinois official site at O’Hare Airport registered an average of 81.1° just short of the 81.3° record set in July 1995. However, the Chicago Midway Airport location, which is more representative of the city itself and also has a much longer period of record (POR) than O’Hare, smashed its all-time warmest month record with an average of 82.6° versus 81.3° in July 1955. Louisville, Kentucky experienced its warmest ever July with an average of 84.5°, but fell short of its single-hottest-month record of 85.0° set in August 2007. Madison, Wisconsin (home of my alma matter!) has just endured its 2nd hottest month on record with a 79.4° average, just short of the record 79.8° set way back in July 1901.

Of course, this is just a short list of the many amazing ‘heat feats’ this past July. I should also mention a couple of the many endurance records that have been set:

Fort Wayne, Indiana: 22 consecutive days above 90° ending on July 18 (old record was 14).

St. Louis, Missouri: 11 days above 105° (old record was 10 in 1934). Also, St. Louis tied its warmest night on record with a low of 86° on July 25th (also occurred on July 24, 1901).

New Asian Heat Record Set?

On a similar topic but different continent, I have late word in from temperature detective Maximiliano Herrera that on July 31st a temperature of 53.6°C (128.5°F) was measured at Sulaibya (Sulaibiya), Kuwait. This location is on the outskirts of Kuwait city and is a water treatment facility.

A Google map image of the location in Kuwait of Sulaibya. Google Earth image.

Although the Kuwaiti meteorological office must make a final determination towards the records validity, a local expert, Dr. Juergen Herrmann (Team Leader Meteorology Specialists, Stanley Consultants, Int’l based in Kuwait) has the following comments in response to a request from Max for additional details:

“We are aware of the new record temperatures. There is no reason why these should not be considered records. Everything is technically OK at the station. You may have detected that the same day we had quiet an amount of other stations in the “vicinity” also have high to record temperatures.

The microclimate at this agro-station is surrounded by high sand dunes and thus has very low wind speeds at 2m height [which] results in a local heat island. Therefore I would not consider this temperature representative for an area bigger than 0.5×0.5km. The next station to Sulaibiya which gives a proper picture for the surrounding area is Jahra – 40586 – and had maximum temperature at the same day of 51.8 deg C. To my best guess this verifies both stations are working properly. Especially as a number of other stations also had really high temperatures that day due to generally low wind speeds with nearly no dust reducing the incoming solar radiation.”

If verified, this would surpass the 53.5°C (128.3°F) measured at Moen Jo-Daro, Pakistan on May 26, 2010. The reading of 54°C (129.2°F) from Tirat Tsvi, Israel on June 22, 1942 remains under suspicion. The Israeli Met. Office pursued an investigation of the record this past year (prompted by an enquiry from the WMO and myself) and concluded it was valid. However, they have refused to make public the details leading to their conclusions, so until they do so the record remains suspect.

KUDOS: Maximiliano Herrera for uncovering yet another possible world record temperature.

Christopher C. Burt
Weather Historian

from:    http://www.wunderground.com/blog/weatherhistorian/article.html