Characteristics of hail in the Croatian coastal part of the Adriatic

Hail is an extreme phenomenon that can cause great material damage. Although the process of hail formation is known, there is still insufficient knowledge about this topic. For this reason, numerous researches on hail climatology around the world have been made in the last few years. In spite of the fact that Croatia is a small country, it has a relatively inhomogeneous climate. The cause of this inhomogeneity may be orography, proximity to the Adriatic Sea etc. Characteristics of hail vary in different climatic conditions, and this research will focus on characteristics of hail in the climactic conditions of costal part of the Adriatic. The results are based on hail data from 55 stations from the observation log for the period from 1973 to 2019, and ERA 5 data for instability indices. The results showed significant interannual and spatial variability, due to which it was necessary to make a division into 4 subdomains. Trend analysis showed negative trend in interannual number of hail events, and the loss of hail events was reflected on summer and autumn seasons. It was shown that on the entire coast, the highest hail activity is present in the colder part of the year, and reduced activity in the warmer part of the year. Daily patterns showed 3 daily highs – morning, noon and afternoon, and the duration was usually 5 minutes. Three stations were singled out as the ones with the most hail days a year: Senj, Drniš and Gračac. Finally, instability indices were studied (KI, CAPE, DLS and freezing level height), which could explain the atmospheric conditions in which hail occurs.