|Above: The planet's deadliest weather-related disaster of April--and of the entire year thus far--was a powerful debris flow that hit the Colombian town of Mocoa in the early hours of April 1. Overflowing rivers mixed with huge amounts of rocks and soil swept through the town, killing 329 and leaving 70 missing. Image credit: Ejército Nacional de Colombia via Facebook.|
April 2017 was the planet's second warmest April since record keeping began in 1880, said NOAA's National Centers for Environmental Information (NCEI) on Thursday; NASA also rated April 2017 as the second warmest April on record. The only warmer April was just last year, in 2016. April 2017 ranked as the eighteenth warmest month (expressed as the departure of temperature from average) of any month in the global historical record in the NASA database. The extreme warmth of January 2017 (thirteenth warmest month of any month in NASA’s database), February 2017 (sixth warmest), March 2017 (fifth warmest) and now April gives 2017 an outside chance of becoming Earth’s fourth consecutive warmest year on record--if an El Niño event were to develop this summer and continue through the end of the year, as some models are predicting. It's more likely, though, that 2016 will remain as the warmest year in Earth's recorded history. For the year-to-date period of January–April 2017, Earth's temperature was 0.95°C (1.71°F) above the 20th century average of 12.6°C (54.8°F). This was the second highest such period since records began in 1880, behind 2016 by 0.19°C (0.34°F).
Global ocean temperatures last month were the second warmest on record for any April, and global land temperatures were the fourth warmest on record. Global satellite-measured temperatures for the lowest 8 km of the atmosphere were the fifth warmest for any April in the 39-year record, according to the University of Alabama Huntsville (UAH).
|Figure 1. Departure of temperature from average for April 2017, the second warmest April for the globe since record keeping began in 1880. Warmer-than-average temperatures during the month were observed across much of the world's land surfaces, with the most notable warm temperature departures from average across the Northern Hemisphere higher latitudes, specifically across much of central and eastern Asia, Alaska and the eastern half of the contiguous U.S., where temperatures were 3.0°C (5.4°F) above average or higher. Image credit: National Centers for Environmental Information (NCEI).|
Three billion-dollar weather disasters in April 2017
Three billion-dollar weather disasters hit the $1 billion mark last month, according to the April 2017 Catastrophe Report from insurance broker Aon Benfield: two severe weather/tornado outbreaks in the U.S., and a $2 billion tropical cyclone in Australia (Debbie). Earth has registered nine billion-dollar weather events in 2017, which is a high number for so early in the year. The year that ended with the most billion-dollar weather disasters in records going back to 1990 was 2013, with 41, and that year had eleven billion-dollar disasters by the end of April. Last year, there were already fifteen billion-dollar weather disasters by the end of April (that year ended up with 31 such disasters). Here are this year’s billion-dollar weather disasters through the end of April:
Flooding, Peru, 1/1 – 4/1, $3.1 billion, 120 killed
Tropical Cyclone Debbie, 3/27 – 4/5, $2.0 billion, 14 killed
Drought, Somalia, Ethiopia, Kenya, 1/1 – 3/31, $1.9 billion, 136+ killed
Severe Weather, Plains, Southeast, Midwest U.S., 3/26 – 3/28, $1.8 billion, 0 killed
Severe Weather, Midwest, Plains, Southeast U.S., 3/6 – 3/10, $1.7 billion, 0 killed
Severe Weather, South U.S., 1/18 - 1/23, $1.3 billion, 21 killed
Severe Weather, South U.S., 2/27 - 3/2, $1.3 billion, 4 killed
Winter Weather, Plains, Southeast, Midwest, Northeast U.S., 3/13 - 3/15, $1.0 billion, 11 killed
Severe Weather, Midwest, Plains, Southeast MS Valley U.S., 4/28 – 5/01, $1.0 billion, 20 killed
|Disaster 1. By the end of April, damage claims from an outbreak of severe weather that swept across the Plains, Southeast and Midwest portions of the United States on March 26 – 28 reached $1.8 billion. Among the hardest-hit areas were Texas, Oklahoma and Kansas, due to softball-sized hail. Isolated tornadoes and straight-line winds also caused damage. Fortunately, no lives were lost. Above, we see a 3” diameter hailstone captured by damage expert Tim Marshall (Haig Engineering) from the storm that struck Double Oak, Corinth, The Colony, and Frisco, TX, just north of Marshall’s house, on March 26, 2017. “Looks like I’ll be booked evaluating the damage through at least mid-summer,” said Marshall. “Spring has roared in like a lion.” Image credit: (c) Tim Marshall, used with permission.|
|Disaster 2. A complex storm system brought severe weather, blizzard conditions, and flooding to the U.S. Midwest, Plains, Southeast, and Misssissippi Valley on April 28 – May 1, killing twenty and causing at least $1.0 billion in damage. Significant flooding hit the Mississippi River basin, particularly in Missouri, Oklahoma, Illinois, and Arkansas. Major hail, straight-line wind and tornado damage was observed in multiple states. Two especially strong long-track tornadoes (an EF4 and EF3) struck near Canton, Texas on April 29, killing four. Above: Significant damage in Canton, TX, from a violent EF4 tornado on Saturday, April 29, 2017, as documented by an NWS storm survey team on Sunday, April 30. This was just the second violent EF4 tornado observed in 2017. Image credit: NOAA/NWS.|
|Disaster 3. Tropical Cyclone Debbie hit Queensland, Australia on March 28 as a Category 3 storm with 120 mph winds, killing at least 14 people. Debbie’s strong winds, torrential rains, and damaging storm surge combined to cause an estimated $2 billion in damage. The remnants of Debbie later triggered flooding in portions of New Zealand. According to figures at EM-DAT, the international disaster database, Debbie was Australia’s fourth tropical cyclone since 2000 to cause at least $2 billion in damage. In this image, we see Tropical Cyclone Debbie just before landfall in Queensland, Australia, on March 28, 2017. Image credit: NASA.|
El Niño on its way this summer?
In its May 11 monthly advisory, NOAA’s Climate Prediction Center (CPC) stated that neither El Niño nor La Niña conditions were present in the Eastern Pacific (ENSO-neutral conditions existed). Sea surface temperatures (SSTs) in the benchmark Niño 3.4 region (in the equatorial Pacific) were about 0.5°C above average over the past week; SSTs of 0.5°C or more above average in this region are required to be classified as weak El Niño conditions (and there must also be an El Niño-like atmospheric response). NOAA forecasters gave a 45% chance of an El Niño event occurring this year—a slight downgrade from their previous month’s forecast, which gave a 50% chance. This reduction in odds was due, in part, to the conflicting model guidance and lack of a clear shift toward El Niño in the observational data. NOAA also advised that the models’ predicted ocean warmth may not last long enough to qualify as an El Niño episode (5 consecutive months, with 3-month average SSTs for each of the 5 months at least 0.5°C above average), and/or the El Niño event may not significantly impact the atmospheric circulation. The May runs of the Australian Bureau of Meteorology models were also less insistent on predicting an El Niño event this summer, compared to the predictions made in April. Predictions made in May of El Niño are of low to medium skill, though, due to the so-called “spring predictability barrier”. El Niño conditions tend to suppress Atlantic hurricane activity by bringing strong upper-level winds to the tropical Atlantic, creating high wind shear that tears storms apart. An impressive surge of enhanced east-to-west blowing trade winds is predicted for the west-central Pacific over the next two weeks, evident in both the GFS and ECMWF models. These unusually strong trade winds will interfere with any progression towards El Niño.
|Figure 2. Sea surface temperatures (SSTs) in the benchmark Niño 3.4 region (in the equatorial Pacific) have been hovering at about 0.5°C above average since mid-April, right at the threshold for weak El Niño conditions. Image credit: Levi Cowan, tropicaltidbits.com.|
Arctic sea ice: lowest extent on record for the seventh consecutive month
Arctic sea ice extent during April 2017 was tied with April 2016 for the lowest April extent in the 38-year satellite record, according to the National Snow and Ice Data Center (NSIDC). Arctic sea ice has set record-low monthly extent records from October 2016 – April 2017. The record low ice extent has been due to a combination of very warm air temperatures plus unusually warm waters invading the Arctic from the south, beneath the ice. Arctic sea ice extent will likely not set a record for May, as the extent has been dropping at a slightly lower pace than usual over the last couple of weeks. However, the total volume of the ice could still be at record low levels for May, based on the huge deficit depicted by the PIOMAS sea ice volume model at the end of April.
Antarctic sea ice no longer setting all-time lows--barely
Sea ice surrounding Antarctica has been at unprecedented lows in recent months, setting an all-time monthly minimum extent record each month during the five-month period November 2016 – March 2017. However, monthly Antarctic sea ice extent in April 2017 was the second lowest for April on record, just behind the record set in 1980.
Notable global heat and cold marks set for April 2017
Hottest temperature in the Northern Hemisphere: 50.0°C (122.0°F) at Larkana, Pakistan, 19 April
Coldest temperature in the Northern Hemisphere: -53.4°C (-64.1°F) at Summit, Greenland, 1 April
Hottest temperature in the Southern Hemisphere: 44.6°C (112.3°F) at Pietermaritzburg South Africa, 4 April
Coldest temperature in the Southern Hemisphere: -72.3°C (-103.5°F) at Concordia, Antarctica, 25 April
(Courtesy of Maximiliano Herrera.)
Major weather stations that set (not tied) new all-time heat or cold records in April 2017
Franceville (Gabon) max. 36.1°C, 19 April
On 19 April, Larkana, Pakistan, recorded 50.0°C (122°F), which is the new Asian record of the highest temperature ever recorded in April.
(Courtesy of Maximiliano Herrera.)
No all-time national heat records set in April 2017
No nations set or tied all-time records for hottest temperature in recorded history in April 2017. So far in 2017, four nations have set or tied all-time national heat records, and two have set or tied all-time cold records. 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.
All-time national heat records set in 2017:
Guinea: 113°F (45.0°C) at Koundara, 29 March (tie)
Ghana: 110.8°F (43.8°C) at Navrongo, 26 March
Chile: 113°F (45.0°C) at Cauquenes, 26 January
Cocos Islands: (Australia): 91.2°F (32.9°C) at Cocos Island Airport, 23 February
All-time national cold records set in 2017:
United Arab Emirates: 22.3°F (-5.4°C) at Jabel Jais, 3 February
Qatar: 34.7°F (1.5°C) at Abu Samra, 5 February
Bob Henson contributed to this post.