March 2013 the globe's 10th warmest March; a billion-dollar U.S. weather disaster

March 2013 was the globe's 10th warmest March since records began in 1880, according to NOAA's National Climatic Data Center (NCDC). NASA rated it the 9th warmest March on record. The year-to-date period of January - March has been the 8th warmest such period on record. March 2013 global land temperatures were the 11th warmest on record, and global ocean temperatures were the 9th warmest on record. March 2013 was the 337th consecutive month with global temperatures warmer than the 20th century average. Global satellite-measured temperatures in March 2013 for the lowest 8 km of the atmosphere were 12th or 8th warmest in the 35-year record, according to Remote Sensing Systems and the University of Alabama Huntsville (UAH), respectively. The Northern Hemisphere snow cover extent during March 2013 was the 16th largest in the 47-year period of record. Wunderground's weather historian, Christopher C. Burt, has a comprehensive post on the notable weather events of March 2013 in his March 2013 Global Weather Extremes Summary. He notes that one nation set an all-time heat record: on March 6th, Navrongo, Ghana reached 43.0°C (109.4°F), the warmest temperature reliably ever measured in the country (for any month.)


Figure 1. March 2013 was the 2nd coldest winter in the U.K. since 1910, exceeded only by March 1962. In this photo taken by wunderphotographer tonylathes on March 24, 2013, we see one of March's heavy snowstorms that affected Wardlow Village in Derbyshire, United Kingdom.


Figure 2. Departure of temperature from average for March 2013, the 10th warmest March for the globe since record keeping began in 1880. The Arctic Oscillation (AO), a large-scale climate pattern that can influence temperatures in the Northern Hemisphere, set a record low for March. This negative phase was associated with frigid Arctic air spilling southward into the Northern Hemisphere middle latitudes, leading to unusually cold conditions in the Eastern U.S., most of Europe, and northern Siberia.This phase of the AO also contributed to much warmer than average and even record warm temperatures in northeastern Canada and southeastern Greenland. A large swath of China and several regions in central and northern Africa in the 0°–20°N latitude belt were also record warm. Image credit: National Climatic Data Center (NCDC) .

First U.S. billion-dollar weather disaster of 2013: March 18 - 20 severe weather outbreak
Two billion-dollar weather disasters occurred globally in March, bringing the 2013 total to five, according to the March 2013 Catastrophe Report from insurance broker AON Benfield. The five billion-dollar weather disasters for 2013 so far:

1) Flooding in Indonesia, 1/20 - 1/27, $3.31 billion
2) Flooding in Australia, 1/21 - 1/30, $2.5 billion
3) Winter weather in Europe, 3/12 - 3/31, $1.8 billion
4) Drought in Central and Eastern China, 1/1 - 3/31, $1.71 billion
5) Severe weather in the Midwest U.S., 3/18 - 3/20, $1 billion

The first billion-dollar weather disaster in the U.S. was a severe weather outbreak that began on March 18, featuring a long-lived squall line of severe thunderstorms called a "derecho" that dropped hail up to softball size from Louisiana to South Carolina. Mississippi was hardest hit, with up to 60,000 insurance claims. Ten tornadoes touched down and two fatalities were reported during the outbreak. The U.S. has averaged 4.4 billion-dollar weather disasters per year from 1980 - 2012, but experienced 25 in the two-year period 2011 - 2012.

The deadliest March weather disaster was an outbreak of severe weather that swept across parts of eastern Bangladesh on March 22. The outbreak included a tornado that struck the regions of Sadar, Akhaura and Bijoynagar in Brahmanbaria district. At least 35 people were killed and 388 injured.


Figure 3. Hail up to the size of tennis balls fell on McComb, Mississippi, as documented by wunderphotographer sirencall On March 18, 2013. The hailstorm was part of a severe weather outbreak that gave the U.S. its first billion-dollar weather disaster of 2013.

Neutral El Niño conditions continue in the equatorial Pacific
For the 12th month in row, neutral El Niño conditions existed in the equatorial Pacific during March 2013. NOAA's Climate Prediction Center (CPC) expects neutral El Niño conditions to last through summer. The large majority of the El Niño models predict neutral conditions will last through the fall of 2013. Temperatures in the equatorial Eastern Pacific need to be 0.5°C below average or cooler for three consecutive for a La Niña episode to be declared; sea surface temperatures were 0.1°C below average as of April 22, and have been +0.1 to -0.4°C from average since March 1, 2013.

Arctic sea ice falls to 5th lowest March extent on record
Arctic sea ice extent during March reached its fifth lowest extent in the 35-year satellite record, according to the National Snow and Ice Data Center (NSIDC). This was the 10th consecutive March and 142nd consecutive month with below-average Arctic sea ice extent. The last ten years (2004 to 2013) have seen nine of the ten lowest March extents in the satellite record.

Jeff Masters