New developments in the diagnosis and verification of high-impact weather forecasts

High-impact weather is of particular interest to forecast users, and its prediction with a seamless ensemble analysis/forecast system is at the heart of ECMWF’s proposed new strategy. Whilst the impacts of weather are user-specific, from a meteorological viewpoint weather can be high-impact by virtue of its extreme amplitude (e.g. tropical cyclones) or its longevity (e.g. heat-waves). Both aspects present a particular challenge for forecast systems, and demand considerable development of diagnostic and verification capabilities. Here, with reference to numerous high-impact weather types, and particular focus on ensemble aspects, we discuss recent developments in these diagnostic and verification capabilities, and our future plans.