August 2012 Global Weather Extremes Summary

August 2012 Global Weather Extremes Summary

There is never a dull month when it comes to extreme weather and August 2012 was no exception. The month began with a massive flood in Manila, Philippines and an intense heat wave in the south-central U.S. Two very sharp heat waves affected much of Europe during the 2nd and 3rd weeks of the month smashing records from Spain to Poland and the Ukraine. Typhoons walloped coastal sections of China and Hurricane Isaac thrashed the U.S. Gulf Coast.

Below is a summary some of the month’s highlights.

NORTH AMERICA

An intense heat wave in the southern plains exacerbated the on-going drought conditions and the temperature at Oklahoma City reached 113°F (45°C), the warmest temperature ever measured in the city. By mid-August, however, a very cool air mass invaded most of the central portion of the country and temperatures even fell to freezing at a few locations in Minnesota and Wisconsin. In spite, of the mid-month cool down some sites have ended up enduring their hottest summer on record. Denver, Colorado has averaged 76.3° for its climatological summer (June-August) beating its former warmest summer of 1954 by a full 2°F (old record was 74.3°F). The warmest temperature in the world during August was 126°F (52.2°C) measured at Death Valley, California on August 9th.

Sub-tropical moisture brought intense rainfall to portions of the desert southwest on August 22nd. Las Vegas, Nevada recorded its 2nd wettest calendar day on record with 1.68” that caused flash flooding resulting in one drowning death in the city. (Mesquite, near Las Vegas, picked up 2.04”, its greatest 24-hour rainfall on record/since 1992). Some other desert locations measured over 4” of rain in just a few hours (4.03” at Mid Hills RAWS in San Bernardino County, California—about what this site might expect in an entire year). One site in Nevada’s Mohave County, Wikieup, received 1.42” of rain in just 30 minutes. Ironically, Seattle, Washington (normally perceived as wetter than Las Vegas!) received no measureable precipitation during the entire month of August, and of this writing, is approaching its record of 51 rain-free days set in 1951 (last rainfall this summer was on July 22nd).

Hurricane Isaac made landfall in Louisiana on August 27 as a CAT 1 storm although its large size, strong storm surge (as high as 13’,) and central pressure (as low as 966mb) was more indicative of a strong CAT 2 cyclone. Seven storm-related deaths were reported mostly associated with the 15-20” rainfalls that fell along the path of the slow moving storm. The damage (at least US$2 billion) caused by Isaac is still under review as of this writing.

Flooding reminiscent of Hurricane Katrina ravaged some New Orleans-area neighborhoods like Plaquemines Parish southeast of the city. Ironically, Isaac struck virtually on the 7th anniversary of Katrina. Photo by Carolyn Cole, Los Angeles Times).

Hurricane Ernesto struck the western coast of Mexico on August 9th resulting in the deaths of two.

The Arctic measured its lowest sea ice extent since observations began in 1975. By August 26th the ice extent had shrunk to 1.58 million square miles, about 277,000 square miles less than the previous record low set in September 2007.

The coldest temperature measured in the northern hemisphere during August was -36.1°C (-33.0°F) at Summit AWS, Greenland on August 30th.

SOUTH AMERICA and CENTRAL AMERICA

Tartagal, Argentina recorded a temperature of 38.8°C (101.8°F) on August 22nd a record for the month at that location.

EUROPE

Europe experienced its most intense heat wave since the famous heat wave of 2003 and, in fact, many locations measured even higher temperatures than that occasion. All-time national heat records were set in the Czech Republic (40.4°C/104.7°F at Dobrichovice on August 20th), Moldova (42.4°C/108.3°F at Falesti on August 7th), and Montenegro (44.8°C/112.6°F at Danilovgrad on August 8th). In the Pyrenees along the French and Spanish border virtually every site recorded its warmest temperature on record. For more details on the European heat waves of August see my previous blog on the subject. Wild fires have raged out of control in both Spain and Greece with several fatalities reported from the Spanish resort area around Marbella.

August weather extremes for the United Kingdom are not yet available.

An intense wild fire threatens a beach resort on the island of Chios in the Greek archipelago on August 18th. Photo from EPA archives.

AFRICA

Monsoonal rains resulted in deadly floods in Nigeria and Cameroon during the month. At least 14 flood-related deaths were reported in Cameroon’s north region and at least 15 in Nigeria’s central provinces.

On August 25th and 26th the temperature peaked at 42.5°C (108.5°F) at Mtunzini, South Africa. This was not only a winter record for South Africa but also close to the warmest temperature ever measured in the southern hemisphere during the winter months (44°C has been recorded at Villamontes, Bolivia during previous Augusts). Needless to say, this was the warmest temperature measured in the southern hemisphere during this past August.

ASIA

Although this years summer monsoons have failed to materialize in much of South Asia, heavy rains in the mountains of northern Pakistan on August 20-23 resulted in flash floods that drowned at least 26.

It was a very active month typhoon-wise in the Western Pacific. Notable typhoons struck Macao and Hong Kong including Typhoon Kai-tak that caused winds to gust to 87 mph at Hong Kong’s International Airport on August 23 and 27 lives were lost in China’s Guangdong and Guangxi Provinces. It was the strongest typhoon to hit Hong Kong since 1999. Typhoon Bolaven was the strongest typhoon to hit the Korean Peninsula since 2002 when it roared ashore on August 28th. At least 18 deaths (mostly fisherman) were reported as a result of the storm with at least a further 48 fatalities reported just recently from North Korea.

The biggest weather story of the month in Asia, however, was the tremendous flood that engulfed Manila in the Philippines between July 31-August 8th. Up to 1000 mm (40”) of rain was reported to have fallen in Quezon City during the week of rains and there were some 60 fatalities reported. For details about the flood see Angela Fritz’s August blog on the subject.

Manila’s streets turned into lakes during the phenomenal flood that affected the city the first week of August. Photo by Jof Cubol.

AUSTRALIA

Australia had a warmer and drier August than normal, reversing (temperature-wise) the cold weather endured over much of the country the previous July. It was Western Australia’s driest August since 1995 and 2nd warmest August on record.

A very warm month virtually nation-wide for Australia this past August (top map). Precipitation was also below normal in most of the country, especially in portions of Western Australia where it was the driest August on record (bottom map). Maps courtesy of the Australian Bureau of Meteorology.

The warmest temperature recorded in Australia during this past August was 38.5°C (101.3°F) at Fitzroy Crossing, Western Australia on August 27th and the coldest -4.9°C (23.2°F) at Thredbo Top Station, New South Wales on August 6th. The greatest calendar day precipitation was 73.0mm (2.87”) at Mount Sabine, Victoria on August 18th.

NEW ZEALAND/SOUTH PACIFIC

It was generally a mild and wet August in New Zealand although there was a sharp contrast in precipitation totals on the South Island where anomalies ran the gamut from 10% to 400% of normal!

The extreme anomaly between very dry and very wet weather that affected the South Island in August can be seen in this map above. Map courtesy of NIWA.

The highest temperature recorded was 22.7°C (72.9°F) at Christchurch, South Island on August 26th and the lowest -5.3°C (22.5°F) at Ranfurly on August 23rd. The greatest calendar day rainfall was 198 mm (7.80”) at Akaroa on August 25th.

ANTARCTICA

The coldest temperature in the southern hemisphere and the world during August was -80.0°C (-112.0°F) recorded at Vostok on August 7th.

KUDOS Thanks to Maximiliano Herrera for global temperature extremes data, Stephen Burt for the U.K. extremes, and Jeremy Budd and NIWA for New Zealand weather extremes.

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