Radar echo characteristics of regional heavy rain process

The regional heavy rain weather data from August 10 to 12,2007 in Yantai were analyzed.The results indicate that the regional heavy rain weather process is formed by the conjunct actions of water vapor of tropical system,uplift of weak cold air in westerly belt and unstable stratification at the edge of subtropical high.Based on the new generation Doppler radar data,many strong convective echo cells are united when they are moving,and come into being a mesoscale convective system(MCS).The stabilization is the direct reason causing heavy rain.Low-level jet can transport a lot of water vapor,and invasion of cold air in the low-level makes upward motion of convection strong.