ASK TOM WHY: May 2007 Archives

This impressive photo of a Friday afternoon (May 25) tornado comes to us from Kurt Coffey, who was scouting corn near Casey, Illinois, when the twister appeared 1/2-mile away. A tornado warning had been issued at 3:02 p.m. by the National Weather Service's Lincoln, Illinois, office on the basis of a Doppler radar indication of rotating winds. It's possible this tornado may be the latest to fall into the "gustnado" category given the fact the circulation appears to have occurred at the leading edge of the thunderstorm rather than in the more conventional rear-southwest quadrant of the storm. Gustandoes form when outflowing winds spin up a vortex at the front of a strong thunderstorm. Our thanks to Kurt Coffey as well as to Mike Toohill, a colleague of Kurt's, who called this remarkable shot to our attention.
--By Tom Skilling, WGN-TV Chief Meteorologist