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Storm-scale Polarimetric Radar Signatures Associated With Tornado Dissipation In Supercells


Polarimetric radar data from the WSR-88D network are used to examine the evolution of various polarimetric precursor signatures to tornado dissipation within a sample of 36 supercell storms. These signatures include an increase in bulk hook echo median raindrop size, a decrease in midlevel differential radar reflectivity factor (ZDR) column area, a decrease in the magnitude of the ZDR arc, an increase in the area of low-level large hail, and a decrease in the orientation angle of the vector separating low-level ZDR and specific differential phase (KDP) maxima. Only supercells that produced “long-duration” tornadoes (with at least four consecutive volumes of WSR-88D data) are investigated, so that signatures can be sufficiently tracked in time, and novel algorithms are used to isolate each storm-scale process. During the time leading up to tornado dissipation, we find that hook echo median drop size (D0) and median ZDR remain relatively constant, but hook echo median KDP and estimated number concentration (NT) increase. The ZDR arc maximum magnitude and ZDR–KDP separation orientation angles are observed to decrease in most dissipation cases. Neither the area of large hail nor the ZDR column area exhibit strong signals leading up to tornado dissipation. Finally, combinations of storm-scale behaviors and TVS behaviors occur most frequently just prior to tornado dissipation, but also are common 15–20 min prior to dissipation. The results from this study provide evidence that nowcasting tornado dissipation using dual-polarization radar may be possible when combined with TVS monitoring, subject to important caveats.

Article / Publication Data
Available Metadata
Fiscal Year
Peer Reviewed
Publication Name
Weather and Forecasting
Published On
December 16, 2021
Publisher Name
American Meteorological Society
Print Volume
Submitted On
April 30, 2021


Not available


Authors who have authored or contributed to this publication.