Hail detection in Naples urban area using single-polarization X-band weather radar: Preliminary results

Naples metropolitan area, one of the most populous in Italy, is highly affected by severe convective storms all year round. Thunderstorm events are sometimes associated with hail precipitation that can cause severe damage to transport activities, especially to aviation. The aim of this work is to develop a radar-based Probability of Hail (POH) index that can help in hail risk management. To achieve this goal, an analysis of 37 thunderstorm events occurred between April 2012 and December 2014 has been carried out, using single-polarization X-Band weather radar reflectivity measurements and ground observations. In order to identify hail from radar data, a method based on VIL-Density radar product (VLD) was applied. An extensive intercomparison between the outcomes of weather radar and ground verification data has been performed using a 2×2 contingency table and statistical scores. The results show that hail is likely to occur when VLD exceed 2.6 g m^-3 warning threshold. The POH index has been tested for a thunderstorm event occurred on May 26, 2012 and has proven to be particularly reliable in hail core detection.