High-resolution numerical simulation of a thunderstorm-induced downburst event and comparison with measured LiDAR wind measurements

Thunderstorms are among the major atmospheric mesoscale threats worldwide. Their simulation is still a challenge for operational and scientific purposes, as well as the forecast of the large damage that might occur at the local scale due to related hazards like windstorms, hailstorms, and intense rainfall. In this research, we focus on the high resolution numerical simulation of a thunderstorm event using the Cloud Model 1 (CM1). The domain of analysis is the Ligurian Sea, a geographical region prone to the development of deep convection because of the presence of steep orography and strong surface heat fluxes, which can enhance thunderstorm strength and lifetime. The chosen event hit the city of Genoa on August 14, 2018, producing a downburst on the ground that was measured by a scanning lidar, a lidar vertical profiler, and several anemometers and met-stations. Different schemes for the microphysics are tested to compare the numerical outcomes with ground measurements of wind and temperature fields. The surface wind fields produced by the longest-lasting thunderstorm cell, which was characterized by a sustained updraft and a strong downdraft due to the interaction of the cloud with the complex orography, are shown in the results and compared with the measured vertical wind profiles.