Abstract: Forecast of a heavy rain caused by the Northeast China cold vortex is always difficult but it is important to weather forecasting operation in the northeast China. Based on a number of tests using combination of different physical parameterization schemes, such as radiation, boundary later and cumulus convection schemes available in numerical weather prediction model, the numerical prediction system for the Northeast China cold vortex has been built. The selection of parameterization is based on synoptic verification score that shows improvement in precipitation forecasting. The system includes physical schemes of long wave radiation, Gayno Seaman boundary layer, Grell cumulus parameterization and mixed phase humidity process. The result shows that the forecast accuracy of precipitation caused by the Northeast China cold vortex is higher using this system than using the operational system of meso-scale numerical forecast in the northeast China. At the same time, the influence of forecast products on the forecast capability and systematic error of precipitation caused by the Northeast China cold vortex are evaluated by a synoptic verification method in terms of density, falling areas and moving velocity of precipitation forecast etc.. The evaluation indicates that the forecastprecipitation intensity is stronger than the real; the forecast falling areas moves to west or south; the forecast scope is smaller than the real. These conclusions have been applied to operational forecast and led to better forecasting results.

Key words: Northeast China cold vortex, Numerical prediction, Physical process, Synoptic verification, Capability evaluation