ECMWF Activities for Improved Hurricane Forecasts

Tropical cyclones are some of the most devastating natural hazards and the “three beasts” Harvey, Irma and Maria during the Atlantic hurricane season 2017 are recent examples. ECMWF is working on fulfilling its 2016-2025 strategy that will significantly improve early warnings for extreme events by use of a high-resolution, earth-system ensemble forecasting system. Several verification reports acknowledge the tropical cyclone tracks from ECMWF as world leading both in deterministic and probabilistic sense. However, producing reliable intensity forecasts is still a difficult task for the ECMWF global forecasting model, especially regarding maximum wind speed. This presentation will show the ECMWF strategy through a tropical cyclone perspective and highlight some key research activities by using Harvey, Irma and Maria as examples. We describe the observation usage around tropical cyclones in data assimilation and give examples of their impact. From a model perspective we show the impact of running at 5-km resolution and also the impact by applying ocean coupling. Finally we discuss the future challenges for tackling the errors in intensity forecasts for tropical cyclones.