The impacts of thunderstorm geometry and WSR-88D beam characteristics on diagnosing supercell tornadoes

Observations of WSR-88D radar data from the tornadic and non-tornadic phases of select supercell thunderstorms are investigated. Under certain circumstances, data artifacts relating to storm cell geometry and WSR-88D beam characteristics can occur and appear very similar to storm-scale circulation signatures. These signatures can be of sufficient magnitude, and possess enough spacial and temporal continuity, to suggest a significant probability that a tornado is occurring or imminent.

This paper discusses the affects of radar beam side-lobe contamination and storm inflow characteristics as causes for a portion of these velocity signatures. Impacts of these signatures to National Weather Service warning operations and storm path-casting are briefly explored.