"It's bad. Real bad," Kemp said.
After the game, the slugger tweeted that, starting with Monday's long ball, he'll donate $1,000 per home run through the All-Star break to tornado relief.
He said he was in junior high school when an E-5 tornado with 300-mph winds hit the same area in 1999 and killed 36 people. He remembered accompanying a cousin who was hit by a foul ball in a baseball game to the local hospital and not knowing the tornado hit until the mangled patients started to arrive.
He vividly described the carnage he saw 14 years ago.
"And this one hit a school," he said. "I know where the schools are. My mom lived in a house in Moore and we gave it to my aunt and uncle. They weren't home today, but they said two blocks away there's nothing left. I've never been through an earthquake, but I've seen what a tornado can do and you just can't even believe it."
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.