This loop of GOES-8 10.7 micrometer InfraRed (IR) imagery shows the development of convection that produced a tornado at Siren, Wisconsin (station identifier KRZN) around 01:20 UTC on 19 June (8:20 PM CDT on 18 June) 2001. The tornado initially touched down around 01:06 UTC (8:06 PM CDT) approximately 10 miles west of Siren, and continued to travel east to about 14 miles east of Siren.
An "Enhanced-V" cloud top signature first became evident on the 00:45 UTC GOES-8 IR image, about 19 minutes before the tornado first touched down west of Siren. Hail up to 1.75 inches in diameter was also reported with this cell (at 01:18 UTC, about 5 miles north of Siren). The line of strong convection to the south of the Siren storm produced hail of 4.5 inches in diameter around 01:30 UTC (33 miles east of Eau Claire, station ID KEAU).