Verification of ensemble flow forecasts for the River Rhine

Ensemble stream flow predictions obtained by forcing rainfall–runoff models with probabilistic weather forecasting products are becoming more commonly used in operational flood forecasting applications. In this paper the performance of ensemble flow forecasts at various stations in the Rhine basin are studied by the means of probabilistic verification statistics. When compared to climatology positive skill scores are found at all river gauges for lead times of up to 9 days, thus proving the medium-range flow forecasts to be useful. A preliminary comparison between the low resolution ECMWF-EPS forecast and the high-resolution COSMO-LEPS forecast products shows that downscaling of global meteorological forecast products is recommended before use in forcing rainfall–runoff models in flow forecasting.