The next generation of NWP: Explicit forecasts of convection using the weather research and forecasting (WRF) model

The performance of daily convection forecasts from 13 May to 9 July 2003 using the Weather Research and Forecast (WRF) model is investigated. Although forecasts using 10-km grid spacing and parameterized convection are not lacking in prediction of convective rainfall, fully explicit forecasts with a 4-km grid spacing more often predict identifiable mesoscale convective systems (MCSs) that correspond to observed systems in time and space. Furthermore, the explicit forecasts more accurately predict the number of MCSs daily and type of organization (termed convective system mode). The explicit treatment of convection in NWP does not necessarily provide a better point specific-forecast, but rather a more accurate depiction of the physics of convective systems.