Forecast convergence score: a forecaster's approach to analysing hydro-meteorological forecast systems
- 1European Centre For Medium Range Weather Forecasts, Reading, UK
- 2Department of Geography, King's College London, London, UK
- 3EU Joint Research Center, Ispra, Italy
- 4Swedish Meteorological and Hydrological Institute, Norrköping, Sweden
- 5Tyndall Centre for Climate Change Research, University of East Anglia, UK
Abstract. In this paper the properties of a hydro-meteorological forecasting system for forecasting river flows have been analysed using a probabilistic forecast convergence score (FCS). The focus on fixed event forecasts provides a forecaster's approach to system behaviour and adds an important perspective to the suite of forecast verification tools commonly used in this field. A low FCS indicates a more consistent forecast. It can be demonstrated that the FCS annual maximum decreases over the last 10 years. With lead time, the FCS of the ensemble forecast decreases whereas the control and high resolution forecast increase. The FCS is influenced by the lead time, threshold and catchment size and location. It indicates that one should use seasonality based decision rules to issue flood warnings.