This project investigates the relationship between the ocean state and European windstorms in the MiKlip decadal prediction system. Relevant oceanic variables and the associated time scales for windstorm development are identified. These results are the basis for the model validation of oceanic processes leading to European winter windstorm development (In cooperation with project VALOCEAN). STOC analyses how far the representation of the identified oceanic variables influences the forecast skill for winter windstorms and extratropical cyclones. This helps understanding and communicating skill found in the operational forecast system, and to explore possibilities to identify oceanic states leading to improved skill.