Based on the observational data of the new generation of weather radar and Micaps conventional da-ta,the tropical depression generating after the decay of typhoon Rammasun landing triggered off the heavy precipi-tation was analyzed to reveal the affecting situation for Yunnan province.The results showed that the typhoon pe-riphery nephsystem had an effect on Yunnan province in the afternoon,on July 19,2014 and the precipitation oc-curred at 5 PM,July 19 in the southeast of Yunnan.Heavy rain weather process for three days during 20 -22,July occurred in Yunnan.The rainstorm and the heavy rain weather process burst out in most parts of the west and the south of Yunnan,of which the precipitation broke through the historical extreme in Pingbian and Ning’er meteoro-logical station.The precipitation process ended in July 23.The precipitation process was the strongest typhoon de-pression which resulted in precipitation in Yunnan province for recent five years.Tropical depression moved west-ward and joined the southwest airflow.The heavy precipitation which resulted from the tropical depression reverse trough continued to affect the west of Yunnan.The tropical depression brought strong rainfall and resulted in major meteorological disasters.The structure and evolution of the typhoon periphery nephsystem could be better identified according to the detection of remote low cloud systems with the observational data of Wenshan new generation weather radar,and there had a better value for improving the short-term warning of heavy precipitation.Increasing the detection of ultra-low elevation under the current body scanning mode contributed to predicting the intensity and developing trend of the windstorm and further improved the warning ability and helped the short-term nowcasting. As soon as the typhoon Rammasun,short-term nowcasting warning operation could be improved under a certain condition by using better radar data.Therefore,there had a certain value for improving the monitoring and early warning level and disaster prevention and reduction with attaching great importance to radar detection.%利用云南7部新一代天气雷达观测数据和 Micaps 常规资料，对台风“威马逊”登陆后减弱生成的热带低压引发强降水进行分析，揭示了台风“威马逊”造成的强降水成因及对云南的影响情况。结果表明：“威马逊”的外围云系于2014年7月19日下午开始影响云南，19日17时滇东南地区出现降雨，其中20－22日，云南省连续3d 出现暴雨天气过程，滇中以西以南大部地区出现大暴雨、暴雨天气（其中屏边站和宁洱站日降水突破了历史极值），23日降雨过程结束。这次台风低压天气过程是近5年来影响云南造成降水最强的一次，热带低压西移与西南气流汇合，低压倒槽造成的强降水对云南西部造成持续影响。热带低压带来了强降水，造成了37人死亡、9人失踪的重大灾害。以文山新一代天气雷达观测资料分析，发现使用雷达对远距离低层云系的探测，能较好地判断“威马逊”台风外围云系的结构及演变情况，对改进强降水的短时临近预警有较好的价值；在现行体扫模式下增加超低仰角探测，应有助于更好预测风暴影响的强度和发展趋势，进一步改进预警能力，从而对短时临近预报有一定的帮助。就台风“威马逊”而言，发现较好的应用雷达资料，在一定的条件下对改进短时临近预警业务有一些帮助，因此提出重视雷达探测可能对提高强天气监测预警水平和防灾减灾应具有一定的价值。
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