March 29, 2015

Antarctica reaches 63F, highest temperature ever recorded.

The warmest temperature ever recorded on the continent of Antarctica may have occurred on Tuesday, March 24, 2015, when the mercury shot up to 63.5°F (17.5°C) at Argentina's Esperanza Base on the northern tip of the Antarctic Peninsula. According to weather records researcher Maximiliano Herrera, the previous hottest temperature recorded in Antarctica was 63.3°F (17.4°C) set just one day previously at Argentina's Marambio Base, on a small islet just off the coast of the Antarctic Peninsula. Prior to this week's remarkable heat wave, the hottest known temperature in Antarctica was the 62.8°F (17.1°C) recorded at Esperanza Base on April 24, 1961. (The World Meteorological Organization—WMO—has not yet certified that this week's temperatures are all-time weather records for Antarctica, though the Argentinian weather service has verified that the temperatures measured at Esperanza Base and Marambio Base were the highest ever measured at each site.) A new all-time temperature record for an entire continent is a rare event, and Weather Underground's weather historian, Christopher C. Burt, has full details in his latest post.  

The Antarctic Peninsula is one of the fastest warming spots on Earth. A 2012 Climate Central post by Michael Lemonick documented how while the Earth as a whole warmed up by 1.3°F between 1900 and 2011, the Antarctic Peninsula warmed by 5°, forcing massive ice shelves to disintegrate and penguin colonies to collapse. A 2012 paper in Nature found that the recent warming is faster than 99.7% of any other given 100-year period in the last 2000 years.

New all-time national and territorial heat records set or tied in 2015
So far in 2015, five nations or territories have tied or set all-time records for their hottest temperature in recorded history. For comparison, only two nations or territories did so in 2014, and nine did in 2013. The most all-time national heat records in a year was nineteen in 2010 (21 records at the time, but two have been broken since.)Since 2010, 46 nations or territories (out of a total of 235) have set or tied all-time heat records, and four have set all-time cold temperature records. Since each of those years ranked as one of the top twelve warmest years in Earth's recorded history, this sort of disparity in national heat and cold records is to be expected. Most nations do not maintain official databases of extreme temperature records, so the national temperature records reported here are in many cases not official. I use as my source for international weather records Maximiliano Herrera, one of the world's top climatologists, who maintains a comprehensive list of extreme temperature records for every nation in the world on his website. If you reproduce this list of extremes, please cite Maximiliano Herrera as the primary source of the weather records. Wunderground's weather historian Christopher C. Burt maintains a database of these national heat and cold records for 235 nations and territories on's extremes page. Here are the national heat and cold records set so far in 2015:

Antarctica set a new territorial heat record of 17.5°C (63.5°F) at Esperanza Base on March 24. Previous record: 17.4°C (63.3°F) at Marambio Base, set the previous day.
Equatorial Guinea set a new national heat record of 35.5°C (95.9°F) at Bata on March 17. Previous record:  35.3°C (95.5°F) at Malabo in February 1957.
Ghana tied the national record of highest temperature with 43.0°C (109.4°F)  at Navrongo on February 12.
Wallis and Futuna Territory (France) set a new territorial heat record with 35.5°C (95.9°F) on January 19 at Futuna Airport.
Samoa tied its national heat record with 36.5°C (97.7°F) on January 20 at Asau. Previously record: same location, in December 1977. 

Amazing rains in the Chilean desert
Unwelcome rains fell this week in Earth's driest place--Chile's Atacama Desert--causing destructive flooding that has left seven people dead and at nineteen others missing. Antofagasta, which averaged just 3.8 mm of precipitation per year between 1970 - 2000, and has a long-term average of 1.7 mm of precipitation per year, received a deluge of 24.4 mm (0.96 inches) during the 24 hour period ending at 8 am EDT March 26. That's over fourteen years of rain in one day! The rains were due to an unusually strong and persistent "cut-off" low pressure system that was trapped over Chile by the exceptionally strong ridge of high pressure that brought the warmest temperatures on record to Antarctica early in the week. A cold front associated with the cut-off low hit the Andes Mountains, dumping rains over soils with very little vegetation (due to the dry climate.) Unusually warm ocean temperatures approximately 1°C (1.8°F) above average off of the coast meant that high amounts of water vapor were available to fuel the storm and generate exceptionally heavy rains. Heavy precipitation eventsare common in Chile during El Niño events, like we are experiencing now. El Niño brings warmer than average waters to the Pacific coast of South America where Chile lies. 


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