Earth has its 4th Warmest April and Warmest January - April Period on Record

April 2015 was Earth's fourth warmest April since global record keeping began in 1880, said NOAA's National Climatic Data Center (NCDC) on Tuesday. NASA rated April 2015 as the 3rd warmest April on record. April 2015's warmth makes the year-to-date period (January - April) the warmest such period on record, and the past twelve months the warmest 12-month period in recorded history. Nine of the ten warmest 12-month periods have occurred within the past two years (the exception: September 1997–August 1998 was tied for eighth warmest.) Global ocean temperatures during April 2015 were the warmest on record, and global land temperatures were the 10th warmest on record. Global satellite-measured temperatures in April 2015 for the lowest 8 km of the atmosphere were the 9th or 16th warmest in the 37-year record, according to the University of Alabama Huntsville (UAH) and Remote Sensing Systems, respectively.


Figure 1. Departure of temperature from average for April 2015, the 4th warmest April for the globe since record keeping began in 1880. A few areas saw record warmth, including Cuba, part of southern Mexico, small parts of west central South America and southern Brazil, regions of Mauritania, and part of eastern Tanzania. Part of north central Russia had April temperatures more than 5°C (9°F) above average. Cooler-than-average temperatures were notable across large portions of central to western Australia, parts of South Asia, central North Africa, and part of eastern Canada. Record cold was not observed over any land areas. Image credit: National Climatic Data Center (NCDC) .


Figure 2. Still frame from a YouTube video by e2theloc of the EF4 tornado that hit Rochelle, Illinois on April 9, 2015. The tornado was part of a four-day severe weather outbreak that killed 3 people and did over $1 billion in damage. This has been the only EF4 tornado in the U.S. thus far in 2015.

One billion-dollar weather disaster in April 2015: Midwest U.S. severe weather April 7 - 10
One billion-dollar weather-related disaster hit the Earth last month, according to the April 2015 Catastrophe Report from insurance broker Aon Benfield: a severe weather outbreak on April 7 - 10 in the U.S. Plains, Midwest, and Mississippi Valley that caused at least $1 billion in damage. So far in 2015, there have been just three billion-dollar weather disasters. However, a fourth--the intensifying drought in the Western U.S.--is likely to cause $3 billion in agricultural damage in California, and another $1.2 billion in damage in the State of Washington. The deadliest weather-related disaster of April 2015 was a massive landslide that hit Badakshan village in northern Afghanistan on April 27, killing 52 people and destroying almost 100 homes. The slide was triggered by a big snowfall event.



Arctic sea ice falls to 2nd lowest April extent on record
Arctic sea ice extent during April 2015 was the 2nd lowest in the 36-year satellite record, according to the National Snow and Ice Data Center (NSIDC). April was marked by surface air temperatures about 1 - 3°C (2 - 5°F) above average throughout the Arctic, except for Greenland and the Canadian Archipelago, where temperatures were 1 - 3°C (2 - 5°F) below average.

Notable global heat and cold marks set for April 2015
Hottest temperature in the Northern Hemisphere: 48.0°C (118.4°F) at Larkana, Pakistan, April 20
Coldest temperature in the Northern Hemisphere: -55.4°C (-67.7°F) at Summit GEO, Greenland, April 11
Hottest temperature in the Southern Hemisphere: 41.5°C (106.7°F) at Borroloola, Australia, April 6
Coldest temperature in the Southern Hemisphere: -76.6°C (-105.9°F) at Concordia, Antarctica, April 22

Major stations that set (not tied) new all-time heat or cold records in April 2015
Cocos Islands (Australia), max. 32.8°C, April 8 (Tied all-time territorial record high)
Navrongo (Ghana), max. 43.3°C, April 10 (New all-time national record high for Ghana)
Ba Don (Vietnam), max. 40.5°C, April 19
Thakhek (Laos), max. 42.0°C, April 20 (Tied all-time national record high for Laos)
Nakhon Phanom (Thailand), max. 42.1°C,  April 20
Roi Et (Thailand), max. 42.2°C, April 21
Nong Phlub (Thailand), max. 41.8°C, April 21
Havana (Cuba), max. 37.0°C, April 26
Holguin (Cuba), max. 38.7°C, April 26
Guaro (Cuba), max. 38.0°C, April 26
Merida (Mexico), max. 43.6°C, April 26
Contramaestre (Cuba), max. 37.7°C, April 27
Velasco (Cuba), max. 38.6°C, April 28
Ciego de Avila (Cuba), max. 38.0°C, April 28
Tela (Honduras), max. 40.6°C, April 28
Coro (Venezuela), max. 43.6°C, 29 April 29 (New all-time national record high for Venezuela)
Puerto Padre (Cuba), max. 38.4°C, April 29
Punta Lucrecia (Cuba), max. 37.3°C, April 29
Nuevitas (Cuba), max. 38.5°C, April 30



New all-time national and territorial heat records set or tied in 2015
As of May 18, 2015, eight nations or territories have tied or set all-time records for their hottest temperature in recorded history thus far in 2015, and one (Israel) has set an all-time cold temperature record. For comparison, only two nations or territories set all-time heat records 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.) 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 researcher 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 wunderground.com's extremes page. Here are the all-time national heat and cold records set so far in 2015:

Palau tied its national heat record of 34.4°C (94.0°F) at Koror Airport on May 14.
Venezuela set a new national heat record of 43.6°C (109.9°F) at Coro on April 29. Previous record: 42.0°C (107.6°F) at Machiques, Zulia State in February 1983.
Laos tied its national heat record of 42.0°C (107.6°F) at Thakhek on April 20.
Ghana set a new national heat record of 43.3°C (109.9°F) at Navrongo on April 10. This is the third time this year Ghana has tied or set a new all-time heat record. Previous records: 43.1°C (109.6°F), set the previous day, on April 9, and 43.0°C (109.4°F) on February 12.
Cocos Islands (Australian territory) tied their all-time heat record with 32.8°C (91.0°F) on April 8.
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. The World Meteorological Organization (WMO) has appointed a committee to study this event and determine if this represents an official record for the continent.
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.
Wallis and Futuna Territory (France) set a new territorial heat record with 35.5°C (95.9°F) on January 19 at Futuna Airport.

Israel set a new national cold record of -14.2°C (6.4°F) at Merom Golan on January 10.

Mr. Herrera originally listed Samoa as tying its national heat record with 36.5°C (97.7°F) on January 20 at Asau, but a subsequent review of the record revealed possible issues with the measurement equipment, so this record is dubious.


Figure 3. This image of the extent of the Saharan Air Layer (SAL) created at 2 pm EDT Wednesday, April 29, 2015, shows that dry, dusty air flowing eastwards from the Sahara Desert was over the Caribbean and northern South America. The associated dry conditions over Venezuela helped bring the hottest temperature ever recorded in that country, 43.6°C (109.9°F) at Coro. Image credit: University of Wisconsin/CIMSS.

Jeff Masters