21 Polarimetric radar observation of a tornado at C-band

Monday, 26 September 2011
Grand Ballroom (William Penn Hotel)
Raquel Evaristo, Valparaiso University, Valparaiso, IN; and T. Lyza, T. M. Bals-Elsholz, A. Stepanek, B. J. Wolf, and K. H. Goebbert
Manuscript (846.9 kB)

Handout (3.4 MB)

On the morning of 26 October 2010 a line of severe thunderstorms passed over the Midwest producing wind damage and a few tornadoes in Wisconsin, Illinois, Indiana, and Ohio. One of the storms initiated a tornado at close range of the VU C-band polarimetric radar (~15km). The NWS rated this as an EF1. The tornado was on the ground for approximately one mile and produced property damage.

The VU radar was running a volume PPI scan with 14 elevations that took about 6.5 minutes to complete, so the tornadic signatures were captured only by two PPI sequences. Nevertheless, the reflectivity, radial velocity and RhoHV signals clearly indicated tornadic signatures. The near 0dB Zdr suggested in the literature was not as obvious since the rain cells were causing strong differential attenuation. We will examine this variable after correcting for differential attenuation.

In this presentation we will show observations from the VU radar during this event.

This work was partially funded by MIT Lincoln Laboratory's NEXRAD Enhancements Program for the FAA.

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