Enhanced detection of tornadoes on 3 May 1999 using prototype fine-resolution WSR-88D measurements

Using simulated WSR-88D Doppler velocity measurements, the authors have demonstrated that enhanced tornadic vortex signatures (TVS) can be produced by decreasing the azimuthal sampling interval from 1.0 deg to 0.5 deg. The authors propose that the conventional 1.0 deg azimuthal sampling interval be cut in half by using half the number of pulses to compute the mean Doppler velocity values (while maintaining acceptable data accuracy).

During the Oklahoma-Kansas tornado outbreak on 3 May 1999, the authors collected prototype WSR-88D data using the WSR-88D Operational Support Facility s KCRI radar in Norman. Archive Level I (time-series) data were collected, starting around the time of the first tornado reports and continuing for the next six hours. Using software developed at the National Center for Atmospheric Research, the Archive I data were converted into two separate Archive II (meteorological) data sets, one having 0.5 deg azimuthal sampling and the other having 1.0 deg azimuthal sampling.

As anticipated, the 0.5 deg azimuthal data produced stronger tornadic vortex signatures. Examples of this enhanced detection capability are presented for tornadic vortex signatures that occurred between 30 and 135 km from the radar.