ZDR column characteristics and trends during the 10 May 2010 severe weather outbreak

On the afternoon of 10 May 2010, supercells developed and moved through central Oklahoma resulting in large hail and numerous tornadoes. All of the supercells in Oklahoma during this event were within range of KOUN, a WSR-88D with dual-polarization capabilities. With the upgrade of the WSR-88D network to dual-polarization in 2011-2012, it is important to continue to investigate the potential operational effectiveness of dual-polarization radar.

One of the potential improvements with dual-polarization radar during severe weather operations is the detection of updrafts via a signature known as the “ZDR column”. The ZDR column is an area of positive differential reflectivity (ZDR) extending above the environmental 0°C level and is indicative of liquid drops lofted in the updraft. Considering the close association of the ZDR column with the updraft, it is valuable to examine this signature for any potential relationship to severe weather occurrence. The main focus of this research will be on the characteristics and trends of the ZDR columns during the 10 May severe weather outbreak, especially with respect to severe weather occurrences. Special attention will be placed on the potential for operational applications.