Terminal Doppler Weather Radar observation of a cyclic tornado supercell

During the afternoon and early evening of 7 June 2008, a supercell thunderstorm developed over northern Illinois approximately 150 kilometers southwest of downtown Chicago. The supercell produced at least eight confirmed tornadoes, including four EF-2 tornadoes, as it moved northeast into the southern suburbs of the Chicago Metropolitan area.

As the supercell tracked northeast, it eventually moved into the range of Chicago's Midway Airport Terminal Doppler Weather Radar (TDWR). The much higher temporal resolution of the TDWR, compared to the KLOT WSR-88D, allowed for much more detailed radar analysis of storm-scale processes that occurred. In particular, this supercell went through multiple cycles where the mesocyclone occluded and weakened, but was quickly followed by a new mesocyclone forming and intensifying to the east of the first.

This study will examine the data from the TDWR and contrast it with that available from the traditional WSR-88D, focusing on the additional storm-scale features that were able to be detected by the higher resolution TDWR.