We're at a time of year now when thunderstorms are few and far between - the average in November is less than one. But a year ago today, some residents of our area were cleaning up the damage caused by not just a thunderstorm, but one that produced a rare November tornado.

On November 26 last year, temperatures reached 67^oF in Wilmington and a record-tying 70^oF in Philadelphia. A cold front approaching from the west lifted this warm humid air, forming a line of powerful thunderstorms, seen on this radar image as the band of red. Around 6 p.m., a tornado touched down in Honey Brook, in western Chester County Pennsylvania, producing winds near 100 mph.

There's a clue in the radar image that a tornado might be forming. The kink in the line in the center of the white circle indicates that rotation is occurring inside one of the thunderstorms. The tornado formed in the middle of that kink about 20 minutes after this image was taken. The twister was on the ground for almost 2 miles, injuring 12 people and causing property damage estimated at $3 million.