Extratropical cyclones are an integral component of midlatitude weather variability and can cause extreme rainfall and windstorms with substantial effects on society. Nevertheless, projections of future changes in cyclone frequencies and intensities are associated with large uncertainties. This project aims to better understand the dynamical processes potentially affecting future cyclone occurrence in the North Atlantic and Mediterranean region. To this end, cyclones in large ensemble simulations of present-day and future climate are investigated based on a potential vorticity perspective and using trajectory analyses.