With everything from lightening, wind and hail, to flash floods and even tornadoes, thunderstorms can be destructive and even lethal examples of nature unleashed. But if what we’ve endured over recent years isn’t bad enough, researchers say we should get prepared for even more such storms later this century. Jeff Trapp, associate professor at Purdue University’s Department of Earth and Atmospheric Sciences says, “Increases in greenhouse gasses will likely lead to increases in the frequency of severe thunderstorms in the U.S.”
Trapp and his team ran computer models of what the weather might look like based upon the increase in the amount of greenhouse gases predicted for the years between 2050 and 2100, and found that many parts of the United States will see a doubling of the number of days with conditions that lead to severe thunderstorms.
He says, “In Atlanta as an example, we saw maybe double the number of days that would be conducive to severe thunderstorms. And, similarly, in New York, say in the month of July as an example, double the number of days that could be conducive to severe thunderstorms.”
The research was published in the December 3, 2007 online early edition of the Proceedings of the National Academy of Sciences and offers some of the most detailed insight yet offered into specific consequences of global warming. In the past, climatologists have been able to talk only generally about overall trends such as an average annual temperature increase of a few degrees. Trapp notes that events such as thunderstorms occur at “too small of a scale” to be recognized in earlier computer modeling efforts. He says increased computing power available only recently is allowing climate scientists the chance to better examine what might happen as the climate changes.
However, he cautions that the research is still about general trends, noting, “We’re not saying that we can use these models to predict a thunderstorm occurrence on May 20th in 2082.” Instead, he says, “we can use the mean (average) occurrences that we see in the models to say something more in detail about the types of storms, about their severity, about their likelihood to produce tornadoes, and so on.”
Trapp says they were hunting for “the conditions that weather forecasters use to be able to assess the likelihood of storms on a given day.” He says this includes the energy force of storms and wind shear, or the difference in wind speed at various distances from the ground.
The models show that thunderstorm activity won’t expand into new regions. Trapp says, “Where we already see severe thunderstorms we’ll see more of them.”
In addition, the storms will still happen at the same general times of the year that they do now. Trapp points to the Midwest as an example, saying, “During the springtime, severe thunderstorms tend to frequent locations say in the Great Plains, and those states will see an increased frequency.”
Not all parts of the U.S. will see this change. While the Midwest and East Coast will see additional activity, Trapp says the computer models show the West will have fewer days with thunderstorm conditions.
The researchers are not yet able to judge severity of those increased storms. Trapp notes, “It’s something we couldn’t really get after,” but is something they hope to learn through additional research.
He says the other additional avenue of research is running these models on other parts of the world to see what the impact might be.
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