May 2012 Global Weather Extremes Summary
May was notable weather-wise for more spring heat records in the U.S.A. and much of Europe. National heat records (for warmest May temperature on record) occurred in Scotland, Greenland, France, and came close to such in Norway and Spain. Globally it was the 2nd warmest May on record (combined land and ocean) and the warmest May on record for the northern hemisphere. Deadly flash floods struck portions of Nepal, China, Afghanistan and the Amazon River reached its highest level on record at Manaus, Brazil. A late season snowfall shocked the city of Sarajevo, Bosnia.
Below is a summary some of the month’s highlights.
The warm spring continued into May for the eastern two thirds of the continental U.S. culminating in 2012 recording its warmest spring (March-May) period on record (since at least 1895). However, unlike March and April, few significant monthly heat records were broken although monthly records were tied in Detroit (95°F), Flint (93°), Cleveland (92°F), and Toledo, Ohio (96°). Chicago’s O’Hare Airport and Midway Airport both registered 97° on May 27th, one degree shy of the monthly May record of 98° at O’Hare and well short of the record 102° at Midway, both set on May 31, 1934.
Precipitation-wise there was a sharp divide between the haves and havenots in the middle of the country: Arkansas reported its 2nd driest May on record while Minnesota endured its 2nd wettest such.
The month was relatively calm so far as tornadoes and severe storms are concerned. The tropical storm season got off to an early start with two named storms (Alberto and Beryl) developing off the Southeast coastline with Beryl making landfall in northern Florida. The storms caused little damage and brought welcome rainfall to the drought-plagued region.
An intense (in relative terms) heat wave affected southern Greenland during the last week of the month. An all-time May high temperature for the country was recorded at Narsarsuaq on May 27th when a reading of 24.8°C (76.6°F) was measured. This was almost as warm as the June record for Greenland (25.2°C/77.4°F) also set at Narsarsuaq on June 22, 1957. Jeff Masters wrote a detailed account of this heat event in his of May 31st.
In spite of the warmth at the end of the month, the coldest temperature measured in the Northern Hemisphere during May was -42.7°C (-44.9°F) at Summit station on Greenland on May 12th.
SOUTH AMERICA and CENTRAL AMERICA
The large Amazonian city of Manaus (population 1.7 million) was inundated by its worst flood in 100 years when the Rio Negro overflowed its banks on May 21st. The city lies near the confluence of the Amazon and Rio Negro Rivers whose headwaters recorded much above rainfall for the month prior to the flooding. Some 2,550 people lost their homes to the floods.
The Amazonian city of Manaus experienced its worst flooding in 100 years when the Rio Negro River overflowed its banks in mid to late May. Photo from International Business Times TV.
Western Europe experienced some periods of record-breaking heat. In France the temperature peaked at 35.2°C (95.4°F) at Le Luc on May 12th, the warmest May reading on record for the country outside of Corsica. In Spain it reached 40.7° (105.3°F) at Seville East, close to the all-time European May record of 42.0°C (107.6°F) set at Diga Lentini, Sicily, Italy on May 23, 1994. Norway came very close to its national May record high temperature when 31.1°C (88.0°F) was measured at Gverv on May 24th. This was the earliest 30°C+ reading on record for the country. The all-time May record of 31.8°C (88.3°F) set in 1908 still stands.
Scotland recorded its warmest May temperature on record when it reached 29.3°C (84.7°F) at Achnagart on May 25th. The coldest temperature measured in the U.K. during May was -6.2°C (20.8°F) at Saughall, East Ayrshire, Scotland on May 5th. The greatest 24-hour precipitation amount recorded was 101 mm (3.98") at Kinlochewe on May 13-14.
A rare heavy May snowfall blanketed the city of Sarajevo, Bosnia with up to 10 cm (4”) of snow on May 14th. Thunder accompanied the storm. Amazingly, it was 27.8°C (82.0°F) just 48 hours previous to the advent of the snowstorm! The temperature fell to 0.6°C (33.0°F) during the snow event.
The hottest temperature recorded in the southern hemisphere during May was 37.8°C (101.2°F) at Pongola, South Africa on May 1st. Kaolack, Senegal apparently measured its hottest temperature on record on May 8th with a reading of 47.8°C (118.0°F) although this reading is suspicious (highest hourly METAR reading was ‘just’ 113°.
An avalanche off the slopes of Mt. Annapurna in Nepal apparently formed a temporary dam on the Seti Gandaki River near Pokhara that burst causing a flash flood in the valley below. At least 71 drowned including 3 Ukrainian trekkers on May 4th.
Flash floods in northern Afghanistan (triggered by 8 hours of torrential rains on May 6th) killed at least 26 with an additional 100 missing in the provincial capital of Sar-e-Pul.
Mudslides caused by heavy rainfall in Gansu Province, China killed at least 44 during the second week of the month. Over 150,000 were evacuated from affected regions.
An all-time record high temperature of 36.7°C (98.1°F) was recorded on the normally temperate resort island of Ko Samui, Thailand on May 1st. In Bangkok the temperature soared to 40.0°C (104.0°F) on the same day, just 0.8°C (2°F) short of the sweltering city’s all-time record high temperature of 40.8°C (106°F).
The hottest temperature recorded in the northern hemisphere and the world during May was 49.5°C (121.1°F) at Moen Jo Daro and Larkana, Pakistan on May 31st.
Australia was, for the most part, drier than normal during May with warmer than normal temperatures in the west and cooler than normal in the north. A small portion of coastal Western Australia around the town of Carnarvon experienced its warmest May on record.
Maps of the maximum temperature deciles (top) and precipitation deciles (bottom) for Australia during the month of May. Courtesy of the Australian Bureau of Meteorology.
The warmest temperature reported for the month was 37.4°C (99.3°F) at Mardie, Western Australia on May 13th and the coldest reading -10.°C (14.0°F) at Charlotte Pass, New South Wales on May 30th. The greatest calendar day rainfall was 215mm (8.46”) at Halifax on May 25th.
NEW ZEALAND/SOUTH PACIFIC
It was a fairly temperate month for New Zealand extreme weather-wise. The warmest temperature for the month occurred at Whangarei, North Island on May 9th with a 23.4°C (74.1°F) reading and the coolest being -81.°C (17.4°F) at Ranfurly, South Island on May 20th. The greatest calendar day rainfall was 207 mm (8.15”) at North Egmont, North Island on May 27th.
The coldest temperature in the southern hemisphere and the world during May was -81.2°C (-114.2°F) recorded at Vostok on May 26th.
KUDOS Thanks to Maximiliano Herrera for global temperature extremes data, Stephen Burt for the U.K. extremes, and Jeremy Budd for New Zealand weather extremes.
Christopher C. Burt