The winning image was taken by Brian Johnson, a storm-chasing photographer, near Wichita, Kan., on May 30, 2012.
Arlington, Va., resident Brian Allen took a shot of a lightning storm over Washington, D.C., from his apartment on Sept. 1, 2012.
University of Wisconsin atmospheric scientist Grant Petty took this photo while on a farm in Dane County, Wis., on May 22, 2011.
University of Central Florida photography student Jason Weingart took this photo of a shelf cloud at the leading edge of a thunderstorm, in Ormond Beach, Fla., on May 15, 2012.
Meggan Wood took this shot on July 5, 2011, in Maricopa, Ariz. She caught a picture of wind whipping up dust just before it engulfed her car, in which she took shelter.