A mesoscale numerical weather prediction model has been developed at the U.K. Meteorological Office and is being tested as an operational short period forecasting tool. It has been constructed with a high degree of flexibility so that it can easily be used in other applications such as pollution dispersal modelling. It has a comprehensive suite of subgrid scale parametrizations modelling vertical turbulent transport, surface and cloud top radiation, surface exchanges, precipitation and penetrative convection. For routine use, a sophisticated initialisation scheme has been devised utilising inputs from its own previous forecast, a larger scale model, and surface synoptic observations. An important interactive analysis element has also been designed into this procedure. Results of cloud predictions are presented which show a useful level of skill.