A small tornado struck shortly after 8 pm Monday evening in Delavan, Wisconsin. It was a relatively small tornado that lasted just four minutes. What’s unusual about this tornado was that it moved from east to west. Most tornadoes move from SW to NE…or W to E. Occasionally there will be a tornado that will move from NW to SE or S to N…but it’s extremely rare to see a tornado move “backwards” from east to west. There was a “closed” low pressure system that passed across N. Illinois. You seldom see that in mid-summer, though there have been several of these this summer.
Peak winds from the twister were estimated at 70 mph, so this was another weak EF0 tornado. The path length was about 3/4 mile and the width of the tornado was approx. 150 yards. Damage was limited to some downed tree branches, some minor building damage, an overturned shed and an overturned dumpster. I think this is the 9th tornado this year in Wisconsin and all have been weak EF0 twisters. Michigan has had just one tornado this year, a small EF0 in Taylor MI on August 1.
Here’s what the Delavan tornado looked like on radar (see middle of the images…standard radar echo in the upper left, velocity on the right.