A Study of Convective Events in Switzerland with Radar and a High-Resolution NWP Model

Three hailstorms which caused significant damage in Switzerland were simulated with the COSMO (Consortium for Small-scale Modeling) one-moment microphysical scheme as well as with the new COSMO two-moment microphysical scheme and qualitatively verified with real radar measurements of the operational Swiss radar network in order to investigate the model capability to realistically simulate convective storms. To this end, a new COSMO radar forward operator was implemented and applied within this study to compute synthetic radar volume data which are then directly compared with the radar derived reflectivities. This is the first time the COSMO two-moment scheme as well as the COSMO radar forward operator is used for COSMO-2 simulations over Switzerland. Using the COSMO twomoment microphysical scheme in forecast mode, resulted in the almost complete absence of convective cells in the simulations.