How Important Are Post‐Tropical Cyclones for European Windstorm Risk?
Elliott Michael Sainsbury, R. Schiemann, Kevin I. Hodges, Len Shaffrey, Alexander J. Baker, Kieran T. Bhatia
Abstract
Abstract Post‐tropical cyclones (PTCs) extend many hazards associated with tropical cyclones (TCs) to the midlatitudes. Despite recent high‐impact cases affecting Europe such as Ophelia, little research has been done to characterize the risk of PTCs. Here we compare the climatologies and intensity distributions of midlatitude cyclones (MLCs) and PTCs in the North Atlantic and Europe by tracking cyclones in the ERA5 reanalysis. Considering hurricane season cyclones impacting Northern Europe, PTCs show a significantly higher mean maximum intensity than MLCs, but make only a small contribution to total windstorm risk. Our results show that a disproportionately large fraction of high‐intensity cyclones impacting Europe during hurricane season are PTCs. The fraction of PTCs impacting N Europe with storm force (>25 m s −1 ) winds is ~10 times higher than that for MLCs. Less than 1% of cyclones impacting Northern Europe are identified to be PTCs. This rises to 8.8% when considering cyclones which impact with storm force winds.