Evaluation of precipitation forecast data as input for hydrological models

In the German administrative setup, meteorology and hydrology are separate. The task to ensure and improve the communication and exchange between the two instances is embedded in the "Co-Design Project" run between the German meteorological service (DWD) and the German flood forecasting authorities. One of the activities in the project focusses on the verification aspect in relation to the use of the flood forecasting centers. 
Here, we present our ongoing work that follows a parallel approach to 
(a)    allow the user, i. e. the flood forecasters to review in retrospect the precipitation forecasts for a specific event, and 
(b)    derive general recommendations for the users concerning the precipitation in different weather models for their application in hydrological models.  
The retrospective analysis is embedded in a web application that can be accessed by the flood forecasters. The event is defined by the user by the choice a catchment area, date and time and a duration. The result is displayed in a predictability plot showing forecasted areal precipitation from different models (deterministic and ensemble) and lead times in combination with the observed precipitation and meteorological return periods from extreme value analysis. 
Routine verification methods applied to the specifics of the hydrological interests will be the base for the recommendations. Here, a focus is on weather model characteristics such as lead time and resolution in combination with weather conditions and the sizes of the catchments of interest, so that especially spatial uncertainty will be addressed. The considered weather models concentrate on the ICON model chain (global, EU, D2, RUC). Also, the added value of ensemble prediction systems is considered.