Customizing and communicating meteorological verification to flood forecasting centers

The quality and reliability of hydrological forecasts strongly rely on the input in terms of precipitation forecasts. A joint project named "Co-Design of innovations between weather and flood forecasting" strengthens the collaboration between the German Meteorological Service (DWD) and regional flood forecasting centers. One major task aims at condensing, tailoring and communicating the complex meteorological verification to the requirements of hydrologists, especially in the face of an increasing number of weather forecast systems.

The currently most advanced precipitation forecast models of DWD are ICON-D2 EPS and ICON-RUC EPS (Rapid Update Cycle). While ICON-D2 is a well-established limited-area forecast model, the ICON-RUC has a similar setup but is initiated every hour (as opposed to every three hours) and is based on a 2-moments microphysics scheme to better account for strong convective events. In contrast, its forecast horizon is presently limited to 14 hours while the ICON-D2 covers two days.

A question relevant to downstream users is if statistical tendencies can be identified with regard to forecast skills at different weather situations, seasons or spatiotemporal scales. Furthermore, the added value of the ensemble runs compared to the deterministic runs will be assessed in order to promote their importance and use, particularly regarding extreme events.

Here, we assess the performance of different meteorological models for different event severities, depending on the geographic location (Germany: Coast, North, South, low mountain ranges, and Alps), season and/or weather situation. A neighborhood verification approach will be used at first while other verification methods will be assessed and potentially customized as required.