A brief analysis of the supercell storm in Croatia on 19 July 2023

Abstract

Supercell storms, or super-Cb, are powerful and long-lasting convective systems that can form within statically unstable air mass in favourable dynamic conditions. These severe storm types are characterized by one or more rotation updrafts, usually supported by environmental vertical wind shear. Severity of these systems is usually reflected in heavy precipitation, large hail, hurricane wind gusts and sometimes derecho or tornado events.

During July 19^th, 2023, super-Cb event hit Croatia, including the capital city, Zagreb. It originated in the western Po River valley, Italy, progressed over Slovenia, Croatia, and finally dissipated over Serbia. Its track crossed about 700 km long path and lasted approximately 9 h, leading to human casualties and heavy property damages.

The synoptic and mesoscale conditions leading to the formation of the super-Cb is analysed and discussed. Regular official station data, synoptic charts, upper air soundings, radar, and satellite observations are deployed as well as WRF model simulation performed for this case scenario. This study contributes to better understanding of such phenomena and their destructive potential in the broader region of Croatia and adds to somewhat scarce research field of such weather in this part of the world.