More reliable extreme weather forecasts
One example of a former hurricane to also affect Switzerland was “Gonzalo” at the end of October 2014. First of all, the storm tore over England and Germany at high speed. It then swept over Switzerland with gusts of wind of up to 185 kph, and kept the police and the fire department very busy: Trees were uprooted, roofs were stripped off, and cellars were flooded due to heavy rainfall. This was followed by winter arriving early, with up to a meter of snow falling in the mountains. Finally, “Gonzalo” moved south towards Greece where its remnants caused snowstorms and flooding.
Former tropical storms also have an effect on weather forecasts in Europe. “On days when former hurricanes push forward into the mid-latitudes,” explains Olivia Romppainen, “the quality of the forecasts often decreases.” The knowledge now gained by the Mobiliar Lab on the links between tropical storms and heavy rainfall on the other side of the Atlantic could contribute to improvements in forecasting extreme weather in the medium term.
Pohorsky, R., M. Röthlisberger, C.M. Grams, J. Riboldi, and O. Martius, 0: The climatological impact of recurving North Atlantic tropical cyclones on downstream extreme precipitation events. Mon. Wea. Rev., 0, https://doi.org/10.1175/MWR-D-18-0195.1