The goal of the WRF (Weather Research and Forecast) model development project is to provide a new mesoscale forecast model and assimilation system that will advance both the understanding and prediction of important mesoscale weather, and promote closer ties between the research and operational forecasting communities. As part of this effort, two Eulerian prototypes have been developed based on a geometric height vertical coordinate and a mass (hydrostatic pressure) vertical coordinate. Both prototypes are cast in flux form and conserve mass, momentum and dry entropy. These rototypes share a rudimentary suite of physics and are being tested by simulating idealized cases and by running real-data forecasts for the continental US twice a day. The WRF model has been released to the community, and we will discuss the strengths and weaknesses of the WRF prototypes in research and NWP applications and briefly outline future plans for the WRF model.