By David Jones | [email protected]
on May 23, 2013 at 4:59 PM, updated May 23, 2013 at 5:24 PM

A former anchor and storm analyst at The Weather Channel in Atlanta (2002-05) and before that chief meteorologist at the Franklin Institute Science Museum in Philadelphia (1998-2002), Jon is a well-rounded pro. He and I became friends years ago through email exchanges.

He really didn't know what he was getting into. Now, I'm the annoyance who interrupts his day with texts and voicemails requesting his opinion on any number of weather events I might notice. Often, it involves whether one of my drives to or from a game will encounter any drama.

Sometimes, it's to consult about potential for severe weather. On two occasions, I was pretty shaken about the potential of one of the big trees around my house falling on the roof during tropical storms. I can always count on Jon to be as levelheaded as Neil Armstrong, though. He's a good guy to talk to when you're rattled.

As any meteorologist who specializes in severe storms, he is endlessly fascinated and awed by tornadoes. The one that ripped through the Oklahoma City suburbs on Monday was something of a landmark event in that neither of us could recall a large tornado so horrifically making a direct hit on a school. This one destroyed two, killing seven students inside one of them.

I wanted to talk to Jon about two aspects of this storm – first, that an EF-5 tornado is rare anywhere but is nearly impossible in south-central Pennsylvania; second, about exactly what creates the destructive force in such a storm.

Last one first: It wasn't just the 200-mph winds that the Moore, Okla., tornado was estimated to have packed. Wind alone cannot do what this tornado did to the Plaza Towers Elementary school or the hundreds of homes in its path – basically scouring them from the earth. It was how slowly this tornado moved, combined with its size and wind speeds, that allowed it to lift so much heavy debris. It is most often weighty projectiles an EF-4 or EF-5 can lift and throw, not the wind itself, that destroys and kills.

“Much of the damage that's done by a tornado this size is done by the debris that's flying around,” said Nese. “Certainly, the human toll. That's how people get killed; they get hit by debris.”

Read the full story: "Penn State meteorologist"