September 2013 Global Weather Extremes Summary
September featured a continuation of unusually warm temperatures in most land areas of the southern hemisphere including Antarctica. A record rainstorm inundated the Front Range of Colorado resulting in a catastrophic flood in the Boulder area. Deadly floods also impacted Romania and parts of Mexico, the latter as a result of Hurricane Manuel. Typhoon Usagi sideswiped Hong Kong. It was the warmest September on record in Australia and the wettest such for Moscow.
Below are some of the month’s highlights.NORTH AMERICA
The biggest story weather-wise in the U.S. during September was the catastrophic flooding in the Boulder, Colorado area following an unprecedented rainfall of 8-15” on September 11-12th. There were nine fatalities as a result of the flooding and several hundreds of millions of dollars in damage.Extreme flash flooding was not only confined to the Boulder area but also occurred in Estes Park, the principle town located in Rocky National Park about 50 miles northwest of Boulder. The above image shows damage to Rt. 34, the highway that leads into the park from the east.
Photo by Dennis Pierce/Colorado Heli-Ops.The Denver metro area was also slammed with up to 15.60” (396 mm) of rain over two days in El Dorado accompanied by heavy hail falls. Snowplows had to clear hail that washed into the streets and accumulated two feet deep in low lying places.
Photographer not identified.
The most powerful early-season extra-tropical cyclone on record struck the Pacific Northwest on September 27-30. Coastal Washington and Oregon saw torrential rainfalls that resulted in the month becoming the wettest September on record for most locations in western Oregon. Details about the storm and its rainfall are outlined in this blog I posted on September 30th.
The first 10 days of the month featured record-breaking heat in the Midwest and East. Des Moines, Iowa reached 101°F (38.3°C) on September 9th, tying its all-time hottest reading for the month. Cleveland, Ohio reached 96°F (35.6°C), its warmest reading for the entire summer.
Due to the U.S. government shutdown, NCDC data for the month’s average temperature and precipitation that I normally post in this summary are not available.
The coldest temperature measured in the northern hemisphere during September was -42.8°C (-45.0°F) at the Geo Summit site, Greenland on September 26th.
Mexico’s east and west coasts were simultaneously slammed by tropical storms in mid-September: Tropical Storm Ingrid hit the northeastern coast north of Tampico and Hurricane Manuel made landfall twice on the southwestern coast. It was the first time since 1958 that both coasts were hit simultaneously.A satellite image of the two tropical systems closing in on both coasts of Mexico on September 15th.
Hurricane Manuel unleashed torrents of rain that caused deadly landslides around Acapulco and in Sinaloa State. At least 138 deaths were attributed to the storms.
In spite of the double whammy in Mexico, it was an exceptionally quiet September for tropical storm development in the Atlantic Basin.SOUTH AMERICA and CENTRAL AMERICA
Wild temperature swings occurred in southern South America during the first half of September (as also occurred in August). Record early spring heat occurred in Argentina and Bolivia with readings up to 42°C (107.6°F) in Argentina on September 10th and 44.0°C (111.2°F) at Villamontes, Bolivia on September 7th. The latter was the warmest temperature observed in the southern hemisphere during the month. Several days later temperatures fell as much as 42°C (75°F) in Argentina and snowfall occurred as low as 800 m (2600’) in Cordoba Province. The Cordoba Aerodrome saw its temperature drop from 40.0°C (104.0°F) on September 10th to -1.5°C (29.3°F) by September 16th!EUROPE
Moscow recorded its wettest September on record with 174 mm (6.85”) of precipitation which included a bit of early season snowfall on the 26th. Torrential rains in the Caucus region caused flash flooding around the Black Sea resort of Sochi delaying construction on the Winter Olympic site. Floods also occurred around Galati in eastern Romania where it was reported by media that about 125 mm (5”) of rain fell in just 6 hours on September 11-12th, equivalent to what would normally fall over a two-month period in the region. Some 700 homes in 12 towns were destroyed or damaged and nine fatalities were reported.A home destroyed by floodwaters in the Romanian town of Comanesti (near Bacau) in the northeastern part of the country.
Photo from BBC.
It was a fairly normal month weather-wise in the U.K. The warmest temperature reported was 30.2°C (86.4°F) at Writtle, Essex on September 5th and the coldest -2.4°C (27.7°F) at Kinbrace, Sutherland on September 6th. The greatest 24-hour rainfall was 71.2 mm (2.80”) at Nunraw Abbey, at Lothian on September 6-7.AFRICA
I am unaware of any extreme weather events worthy of mention in Africa during September.ASIA
Extreme heat hit the Persian Gulf region early in the month with the temperature peaking at 50.0°C (122.0°F) at Mitribah, Kuwait on September 5th. This was not only the hottest temperature reported in the world last month but also the first time a reading of 50°C has been reliably measured anywhere in the world outside of North America during the month of September.
Typhoon Usagi gave Hong Kong a scare in mid September when the CAT 3 storm narrowly avoided making a direct strike on the city. Usagi did, however, cause considerable damage to the region in China just to the north of Hong Kong, where 24 fatalities occurred in Guangdong Province. An additional 13 people perished in the Philippines where the storm passed over earlier. A man runs from a huge wave crashing ashore on a wharf in China’s Guangdong Province on September 23rd as Typhoon Usagi made landfall with 100 mph (160 km/h) winds.
Photo from AFP.
Other typhoons of note during the month were Man-yi that pounded Japan with heavy rain and high winds (gusts to 100 mph) on September 16th and killed five, and Typhoon Wutip that struck central Vietnam on September 30th.
Thailand experienced one of its wettest months on record this September when the summer monsoon finally kicked in after a dry start in June-August. Thirty-two out of the country’s 77 provinces reported flooding during the month and at least 23 lives were lost as a result.AUSTRALIA
Australia experienced not only its warmest September but also its most anomalous single month (any month) temperature-wise on record. The mean temperature for the nation as a whole was 2.75°C (4.95°F) above normal. The previous greatest anomaly was +2.66°C (+4.79°F) in April, 2005. Precipitation averaged close to normal thanks to generally wetter conditions than average in the west but drier than normal in the east.Precipitation (top) and temperature (bottom) deciles for the month of September in Australia. It was by far the warmest September on record for the continent.
Maps courtesy of the Australian Bureau of Meteorology.
An astonishing temperature (for the time of year—late winter) was measured at Fitzroy Crossing, Western Australia on September 2nd when 41.1°C (106.0°F) was attained. The same site went on to measure 41.6°C (106.9°F) on September 27th, the hottest reading in Australia for the month. The coldest temperature measured was -3.1°C (26.4°F) at Mount Wellington, Tasmania on September 11th. The greatest calendar day rainfall was 220.4 mm (8.68”) at Robertson, New South Wales on September 17th.NEW ZEALAND
A strong cold front passed over New Zealand on September 10-11 bringing wind gusts of 133 km/h (83 mph) to Christchurch and 4000 lightning strikes to the South Island. The warmest temperature measured during the month was 24.2°C (75.6°F) at Kaikoura, North Island on September 11th and the coldest -6.4°C (20.5°F) at Albert Burn (near Wanaka), South Island on September 14th. The greatest calendar day precipitation was 253 mm (9.96”) at Mt. Cook, South Island on September 10th.ANTARCTICA
The coldest temperature in the southern hemisphere and the world during September was –77.4°C (-107.3°F) recorded at Vostok on September 1st. Like August, it was the warmest September on record for the Amundsen-Scott South Pole station with an average of -51.2°C (-60.2°F), some 7.9°C (14.2°F) above normal. The past six months have been the warmest such period on record for the Antarctic interior dome region with a departure from normal since April 1st of 2.7°C (4.9°F).KUDOS
Thanks to Maximiliano Herrera for global temperature extremes data and Jeremy Budd and NIWA for New Zealand data.
Christopher C. Burt