Comparison of Three Cloud Schemes in Winter Storm Forecasts

Abstract

To improve cloud and precipitation forecasts in the Canadian numerical weather prediction system, three cloud schemes with various degrees of complexity are evaluated. Several winter cases are simulated and mesoscale forecasts are compared with satellite, radiosonde, and surface observations. In particular, the distribution of cloud-top pressure is studied in detail using Geostationary Operational Environmental Satellite-8 (GOES-8) data. The three-dimensional structure of temperature and moisture is compared with upper-air data and forecasts of surface precipitation are scored against synoptic observations. This study demonstrates that the operational Canadian cloud scheme has problems that can be partially addressed by the inclusion of more realistic cloud microphysics in the forecast system.