Polarimetric radar characteristics of a supercell hailstorm on 10 May 2010 in central Oklahoma

During the afternoon of 10 May 2010 numerous supercell thunderstorms developed and passed through Central Oklahoma. One storm in particular developed southwest of the Oklahoma City metro area and moved through the southern and eastern sides of Oklahoma City that produced up to softball-sized hail over a large area, and caused extensive damage.

This storm was in close proximity to three WSR-88Ds, one of which had dual-polarization capabilities. Preliminary results indicate this storm had a very wide, well-defined bounded weak echo region (BWER) and storm tops over 60,000 feet above mean sea level (MSL) indicating a wide and very strong updraft supportive of the giant hail that fell. However, weak reflectivity values near the hail locations did not provide high confidence of large hail. In the dual-polarization variables, the areas of softball sized hail were associated with very low differential reflectivity (ZDR < 0 dB) and low correlation coefficient (CC < 0.85) which is a classic large hail signature despite the low reflectivity values. Therefore, the combination of current conventional base moments and dual-polarization variables could have provided the forecaster with better information and higher confidence when issuing a warning for that storm. With the imminent upgrade of the WSR-88D network to dual-polarization, this paper will focus primarily on the dual-polarization signatures, such as those mentioned above and others associated with this storm and their operational significance.