A single thunderstorm cell developed in Rock county Tuesday evening producing an EF0 landspout tornado. The first report of a funnel cloud was received at 7:55 pm from a pilot flying into the Janesville airport. A Tornado Warning was then issued at 8 pm. Subsequent funnel and tornado reports were received from the Janesville aiport tower, trained spotters and the public.
A damage survey and radar images indicate the tornado touched down at approximately 8:10pm and moved southeast with an intermittent damage path 1.6 miles long. The tornado produced minimal damage around Clear Lake. A screen porch including metal foundation was flipped over a trailer just southeast of Clear Lake. Some tree and powerline damage was also observed mostly southeast of Clear Lake.
This storm was very small in size and the only one in southern Wisconsin Tuesday evening. The first funnel cloud reports came in just 15 minutes after the cell developed. It weakened and the cell dissipated about half an hour later.
A landspout tornado is one that is not associated with a broad area of rotation known as a mesocyclone. Landspout tornadoes are normally smaller and weaker than the average supercell tornado.
This metar report was received from the Janesville airport at 8pm. It's pretty rare for airport observers to see and report a tornado in their official observations.
SPECI KJVL 240100Z COR VRB03KT 10SM +FCRA FEW055CB BKN180 28/23 A2988 RMK TORNADO N MOV S
Below are a couple pictures taken by Gina Gehring from Jefferson, looking south. The first picture was taken around 755 pm and the second was taken around 808 pm.
Some damage pictures are shown below.
0755 PM FUNNEL CLOUD 3 SE EDGERTON 42.81N 89.03W
06/23/2009 ROCK WI AIRPLANE PILOT
AIRPLANE PILOT SPOTTED FUNNEL CLOUD ALMOST TOUCHING THE
GROUND NEAR EDGERTON.
0810 PM TORNADO 5 SE EDGERTON 42.79N 89.00W
06/23/2009 F0 ROCK WI NWS STORM SURVEY
A STORM SURVEY DETERMINED AN EF0 TORNADO TOUCHED DOWN
NEAR CLEAR LAKE...OR 5 SE OF EDGERTON. A SCREEN WAS
FLIPPED OVER A TRAILER. MINIMAL TREE AND POWER LINE
DAMAGE WAS ALSO OBSERVED MAINLY TO THE SOUTHEAST OF THE