Pseudo-Global Warming Simulations Reveal Enhanced Supercell Intensity and Hail Growth in a Future Central European Climate

Abstract. Germany is heading toward a future with warmer temperatures due to climate change and potentially cleaner air from electrification and stricter emissions. But how will these evolving environmental conditions affect severe convective storms? This study addresses this question by simulating three supercell events in high resolution using the ICOsahedral Non-hydrostatic model. The events observed during the Swabian MOSES field campaigns in 2021 and 2023 are analysed using the pseudo-global warming approach to assess their evolution in a warmer climate. Aerosol effects were incorporated across all temperature scenarios using a double-moment microphysics scheme, providing detailed insight into the underlying microphysical mechanisms. The results show that higher temperatures generally enhance convection, leading to more intense convective cells, increased precipitation amounts, and more extreme rainfall and hail. Additionally, warmer conditions increase the likelihood of supercell formation and more intense mesocyclones. An important finding is that hailstones grow larger under lower CCN concentrations, and the area affected by large hail expands by up to 400 %, indicating growing severity and reach of hail events. In some cases, precipitation increases exceed 7 % K^-1, indicating super-Clausius–Clapeyron scaling and suggesting that additional dynamical and microphysical processes amplify rainfall beyond thermodynamic expectations. In addition, lower CCN concentrations are associated with a reduced cold-to-warm rain formation ratio and decreased precipitation efficiency. These aerosol-related effects appear largely independent of temperature, showing consistent patterns across all simulated warming scenarios. These findings indicate the intensity of severe weather events, such as convective storms and flash floods, may increase in a future climate.