Delaware Public Media

iSeeChange: Are thunderstorms on the rise in the mid-Atlantic?

Aug 20, 2015

Thunderstorms are a hallmark of summer in the mid-Atlantic. Warm, wet air makes the atmosphere unstable, bringing thunder, lightning, high winds and heavy rain to the region -- sometimes several times a week.

Delaware has seen some particularly memorable storms in recent months -- and they're making quite an impression. In our latest installment of iSeeChange, Delaware Public Media's Annie Ropeik finds out why.

 

 


Growing up in southern Delaware, John Painter says thunder and lightning didn't faze him.

"I remember being outside and playing almost all summer, all day long," he says.

Now, when his kids have to deal with thunderstorms, "they're terrified of 'em," he says, laughing.

"They're seven and four, and when they hear someone talking about, 'I hear there's a big storm coming tonight,' they already start getting into panic mode, planning -- 'Can I sleep in your bed, or what's going on,'" he says. "It already has an effect even before it happens."

Painter, who is public relations director at Delaware Technical and Community College, says even he gets nervous about his kids being outside during storms. He  says the thunder and lightning seem more intense now than when he was young -- and like they happen more often.

"I do wonder if there is a change, or maybe it's just my perception. When you're a kid, you're not really worried about that stuff," Painter says. "But I just feel like now, especially with these thunderstorms -- I don't recall such severe storms where I felt like a tornado or something could pop up any minute happening almost every other night."

Worse storms in the summer, and more of them -- or does it just seem that way?

"As far as we can tell, the thunderstorms are very much now the way they have been, as far back as we have records," says Delaware's state climatologist, Dan Leathers. He's also a professor at the University of Delaware. "I think the big thing that has changed is everybody's ability to share information about the thunderstorms that are occurring and to gather information."

That was the case with one big thunderstorm in late June. It brought high winds that downed power lines and tree branches, blocked roads and damaged cars and buildings in northern Delaware. Power was out for days in some spots -- and around the region, social media was flooded with pictures of damages and the neon orange sunset after the storm.

Leathers says that event did cause a notable amount of damage -- but it wasn't unheard of for this time of year.

"If it had happened 30 years ago, people would have known about it, there'd have been some discussion about it. But it got a large amount of press and amount of photos that people took and videos that people took while the storm was occurring, et cetera -- they were just splattered all over the Internet," he says. "And I think people now look at those and they say, 'Wow, look at what happened over there,' and that kind of goes in their mind as a thunderstorm taking place."

Leathers says scientists don't much yet about how climate change is affecting this kind of weather.

"There's been no really conclusive discussion about especially severe weather, things like tornados, high winds, hail, and anything to do with climate change," he says.

 

But he says some research has drawn a connection between warming temperatures and heavier rainfall in other parts of the country. He's less sure about Delaware, though the First State did see its second-wettest June on record this year.

"As the air warms, we also very often have more water vapor in the atmosphere," Leathers says. "When thunderstorms take place, that you can wring that water vapor out and give you some very heavy rainfall."

As for those tornados John Painter was worried about -- Leathers says they're less common in the eastern U.S. than in the midwest. But this region's geography does contribute to its stormy summers -- for the same reason the west coast rarely sees thunderstorms.

"Land surfaces heat up and cool down much faster than ocean surfaces, and so … we tend to get, in the summertime, pretty warm air coming into our area, because that whole continent out to our west is heating up and that air is moving toward us," Leathers says. "But we're also in the part of the country where we can get the deep moisture coming in from the Atlantic and the Gulf of Mexico very often."

And that combination creates heat, humidity and instability. In late summer, Leathers says cold fronts move in after hot humid days -- pushing hot air up into the atmosphere and generating storms.

Besides social media buzz, that generates one other thing: more visible warnings from the National Weather Service, "and better warnings, because of the increase in technology," says Leathers. "It might make people worry a little bit more, but it also very likely saves lives and property."

And that buzz won't necessarily die down as the summer ends. In colder weather, Leathers says the mid-Atlantic is also liable to see thundersnow.

"And that's because even in the wintertime, different layers of the atmosphere can be unstable enough to be able to give you essentially thunderstorms, but with temperatures cold enough that it's snow falling," he says. "So that's pretty cool when that happens."

And it's always popular with storm chasers -- so Leathers says you'll hear plenty about it if it occurs this year, whether or not there's more of it.