Potential Tornado Warning Improvement Resulting from Utilization of the TDS in the Warning Decision Process

Abstract

Polarimetric tornadic debris signatures (TDSs) provide a means of confirming that a strong wind field has lofted debris to the altitude of the radar beam. They can increase confidence in an ongoing tornado, which may be noted in tornado warning text to increase the sense of urgency. They may also serve as indicators of weak tornadoes that may otherwise go unwarned. Polarimetric data have been available since 2012 on a large portion of the U.S. Weather Surveillance Radar-1988 Doppler (WSR-88D) network and since May 2013 for the entire network. It is anticipated that use of the polarimetric TDS in the tornado warning process should evolve through time. Thus, this paper presents an overview of how the TDS was used in the warning process during the 16 months when widespread polarimetric data were first becoming available (February 2012-May 2013). During this period, 22.5% of tornado warning texts for TDS-producing events mentioned the TDS. It is estimated that utilization of the TDS in the warning decision process could result in ~45 previously unwarned tornadoes being warned annually, and in ~65 tornado warnings being issued with a less negative lead time.Examples are shown that demonstrate potential operational usefulness of the TDS. ABSTRACT (Manuscript