Based on Doppler radar data,wind profiler radar data and high-density observations of AWSs(automatic weather stations),a heavy rainfall event in Tianjin during 25—26 July 2012 is investigated.Results show that:(1)The radar echo shows the high centroid structure during the heavy rainfall event,and the cyclonic convergence with updraft is closely linked with rear downdraft,indicating that the convection has certain organizations and the strong rain echo will not be weakened in a certain time so the heavy rainfall will be continued.The maintenance and extended height of adverse wind region can be used as a threatened signal of heavy rainfall.(2)The surface convergence line is in good agreement with “train effect” area on the radar echo map.The mesoscale surface convergence center and the steady maintenance of meso- and micro-scale convergence are important factors affecting the rainstorm.(3)The disturbance process of low level jet and boundary layer jet can be analyzed in detail based on the wind profile data.The jet is significantly strengthened before the heavy rainstorm,which is consistent with “train effect” on the radar echo map,but can be warned more earlier than radar.The enhanced characteristics of low level jet and boundary layer jet from the wind profiler radar have a good indicative significance for the short-term weather forecast of heavy rainfall.