Validation of hydrometeor prediction by global models is an important issue as it pertains to the accuracy of climate predictions. In this study we use data from a continuously operating millimeter wave radar at a research site in north central Oklahoma, USA to validate output from the operational ECMWF forecast model. We demonstrate that the ECMWF model shows good overall skill at predicting the vertical distribution of the clouds and precipitation that occurred over this site during winter 1997. However, we also show that the model tended to predict the onset of deep cloud events too soon, made the layers too deep and predicted dissipation somewhat later than observed. ¿ 1998 American Geophysical Union