Professor Grant Petty's winning photo (click to view full size).
Grant Petty is a professor of Atmospheric Science at the University of Wisconsin-Madison. He's also an avid photographer.
One of Petty's photos earned acclaim last month as part of NASA's GPM (Global Precipitation Measurement) Extreme Weather Photo Competition. Petty was taking pictures at a farm in Dane County in May 2011 with a photography club when a thunderstorm to the east caught his attention.
"This is one of many examples of how a completely unplanned photo wound up being among my best," he told NASA.