Using the MICAPS weather map, ground encrypted observation data, radar products and NCEP 1°×1°6 h reanalysis data,the circulation background, physical characteristics and radar echo of a local heavy rainstorm were analyzed in Kaifeng City of Henan Province on July 19, 2016.The results showed that the process of heavy rainfall was caused by the combination of low-level vortex, shear line and ground trough in the process of northward extension of subtropical high.Southwest low-level jet to strengthen the north lift, providing a strong thermal instability conditions;Southwest low-level jet to strengthen the north lift, which provide a strong thermal instability conditions;East and south of the ultra-low-level jet transported plenty of water vapor to the storm area.Ground small scale convergence system was the main lifting trigger mechanism,the location of the convergent center corresponds to the local heavy rain falling area.The presence of the 0.5°elevation angle up-wind zone in the radar velocity field provided a favorable criterion for the timely warning of rainfall .%利用MICAPS天气图、地面加密观测资料、雷达产品以及NCEP 1°×1°6 h再分析资料,对2016年7月19日河南开封出现的一次局地大暴雨过程的环流背景、物理量特征、雷达回波等进行了分析.结果表明,此次大暴雨过程是在副热带高压西伸北抬过程中,高空槽配合低层低涡、切变线、地面倒槽共同作用下产生的;西南低空急流的加强北抬,提供了较强的热力不稳定条件;偏东和偏南超低空急流向暴雨区输送了充沛的水汽;地面中小尺度辐合系统则是主要的抬升触发机制,辐合中心的位置与局地大暴雨落区对应较好.雷达速度场上0.5°仰角逆风区的出现,为暴雨及时预警提供了有利判据.
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