Heat records standing since 1895 were broken in March, according to the National Weather Service. All 50 states broke at least one record for high temperatures.
Abnormally warm air fueled 223 tornadoes in March—a huge jump from the approximately 80, according to preliminary reports from the National Oceanic and Atmospheric Administration’s (NOAA) Storm Prediction Center. Hawaii had a rare tornado on the island of Oahu, and the largest hailstone ever observed in the state—4 and a half inches.
The unusually early March tornado outbreak was the first billion dollar natural disaster of the year.
The March 2012 Monthly Climate Report for the United States, released Monday, said all the contiguous states had record high temperatures during the first quarter of the year. The average temperature was 42 degrees Fahrenheit—6 degrees above normal.
Long term, the climate over the United States has been on a warming trend at a rate of about 0.38 F degrees per decade, according to Dr. John Christy, a professor of atmospheric science and director of the Earth System Science Center at the University of Alabama-Huntsville.
Yet this dramatically warm month was a fluke, he said in a statement from the university. “We see hot and cold spots over the globe every month, and this was just our turn. A one-time anomaly like this is related to weather rather than climate,” Christy said. “Weather systems aligned in March in a way that changed normal circulation patterns and brought more warm air than usual to the continental U.S.”
The weather systems Christy spoke of include “an active jet stream which stayed mostly along or north of the U.S.-Canadian border, allowing warm southerly air to dominate most of the country east of the Rockies,” according to a report from NOAA. La Nina, meaning unusually cool equatorial Pacific Ocean temperatures, continued to influence weather.
La Nina is associated with hotter-than-normal weather for the Eastern half of the United States. Both La Nina and El Nino cause weather extremes, from droughts to downpours, from heat waves to deep freezes.
Iowa was the hottest place in the world in March, compared to seasonal norms, according to a statement from UA-Huntsville. Iowa had temperatures 11 degrees higher than normal. Alaska was the coolest, at 5.2 degrees below its average temperatures.
East of the Rockies, 25 states had the highest temperatures on record. The NOAA report said, “15,272 warm temperature records [were] broken; 7,755 daytime records, 7,517 nighttime records,” including 21 occasions when night temperatures broke daytime heat records.
The reports are preliminary as some weather stations still file reports by paper and U.S. mail, the agency said.