Q. Tornadoes are prevalent every spring, but this year's tornadoes seem to have produced more violent storms than usual. Is there any explanation for this? -- Sarah Cooper, Gainesville
A. WSB Radio meteorologist Kirk Mellish told Q&A on the News that an active severe weather season was in his long-range forecast for spring -- issued March 3 -- because it matched similar patterns of past La Nina springs with a similar solar cycle, such as 2008 and 1974. He directed Q&A on the News to past blogs (found at www.wsbradio.com/weblogs/kirk-mellishs-weather-commentary) that explain the reason, such as this comment in an April blog: “Typical of the La Nina temperature contrast clashes, the national tornado threat is elevated ... as the stronger-than-normal jet stream provides increased wind shear for rotation in storm cells.” The temperature contrast -- warmer-than-normal South and colder-than-normal Northern U.S. -- resulted in a strong jet stream frontal battle zone between the regions. It was aided by warmer-than-normal water in the Gulf of Mexico, which fueled bigger storms, he wrote. The 2008 La Nina year saw 1,689 tornadoes across the country, the second highest number in 59 years. “Research has linked La Nina conditions in the Pacific Ocean to a greater number of tornadoes, stronger tornadoes, longer tracked tornadoes and greater likelihood of ‘tornado swarms’ of three dozen or more tornadoes in single outbreaks,” he wrote.
Lori Johnston wrote this column. Do you have a question about the news? We’ll try to get the answer. Call 404-222-2002 or e-mail q&a@ajc.com (include name, phone and city).
About the Author
