I joined the predictability section of KNMI in 1990. During 1995-2002 I worked at ECMWF, where I contributed to the development of the Ensemble Prediction System. At the moment I am leader of the meso-scale modelling section in the R&D Weather and Climate modelling department. Central theme of my research is the interface between predictability and data-assimilation. I have explored this in various projects, ranging from weather to climate applications. Currently I am involved in setting-up a HARMONIE ensemble and data-assimilation system. To facilitate the data assimilation effort, in particular the 4DVAR approach, two internal MSO proposals have been granted.