IBHS Hail Field Research Project 2014 Case Studies: Comparison of Polarimetric Radar Observations and Surface Hail Characteristics

In the spring of 2014, the Insurance Institute for Business and Home Safety (IBHS) deployed on several storms in the U.S. Great Plains in an effort to measure the physical characteristics of hailstones observed at the ground (Brown et al. 2014, this conference). One of the major goals of the IBHS field project is to improve radar-based detection and sizing of hailstones. In this study we will present several case studies comparing polarimetric WSR-88D radar data to the IBHS hail observations. Specifically, radar-based hail “swaths” are generated based on several different techniques, including those based on radar reflectivity only and those utilizing the polarimetric radar variables. Surface observations of hailstone physical properties (including size, shapes, and qualitative information about their size distribution) are used to evaluate the different radar-generated swaths, including their lateral extent and radar-inferred maximum sizes. In addition, radar signatures aloft that may serve as precursors for severe and significantly severe hail are explored relative to the locations of such hail at the surface.