A Comparison of WSR-88D and DOW radar Observation of the 3 May 1999 Oklahoma City Tornado

The central Oklahoma WSR-88D (KTLX) observed the violent Oklahoma City tornado during all of its lifetime (2327-0047 UTC) at relatively close range (~20-50 km). Two Doppler On Wheels (DOW) radars also observed the tornado during its lifetime at very close range (~3-8 km). The data from one of the DOWs was nearly continuous and contained sector scans with elevation angles to 18 deg for a substantial portion of the tornado's life (0000-0035 UTC). Analysis of the DOW data provides detailed information on the high-resolution velocity field in and around the tornado. Good estimates of tornado structure and evolution are obtained. The DOW data are compared to the lower-resolution WSR-88D observations to determine how much tornado information is lost due to the broader beam width (longer range) and longer gate length. Special emphasis is given to measurements of tornado rotational velocity and diameter. Results of the study will be useful in determining how best to interpret future WSR-88D observations of near-range tornadoes, including possible real-time estimation of tornado intensity and evolution.