Abstract:Based on the routine observation data and the Doppler weather radar data, the synoptic patterns and radar echo features of four heavy rainfall events at the edge of western Pacific subtropical high in Hunan from 2003 to 2004 are analyzed. It shows that the position of the western Pacific subtropical high, the upper-trough, the southwest jet stream, low vortex, shear line and cold front in surface are responsible for precipitation. In base reflectivity picture, the heavy rainfall of warm shear line, the heavy rainfall of cold shear line and heavy rainfall of trough are characteristic by narrow band echo feature from south to north, cumulostratus echo feature from west to east approximately and cumulostratus echo feature from northeast to southwest respectively. In Doppler radial velocity picture, there are low-level jet, cold(warm) advection, cold front, averse wind region, the upper strong wind core feature and so on. When several features appear at the same time, the heavy rainfall event will likely appear.