Abstract:Using NCEP/NCAR (2.5°×2.5°) reanalysis data, conventional and unconventional data and based on the environmental and mesoscale characteristics, this paper analyzes the impact of the superstorm “Phailin” in the Bay of Bengal on the severe precipitation in Tibet. The results show that after Phailin’s landing, it weakens into a low pressure. The development of the low pressure clouds is divided into two stages, forming three mesoscale convective cloud cluster, which controls the Tibetan Plateau severely under the influence of southern branch. The occurrence of severe precipitation has direct corresponding relations with the speed of southern winds. The southern part of Tibet does not see severe precipitation until the establishment of the low level southwestern jet while the establishment of the low level jet results from the contribution of the southern branch. The important relationship between the speed of southern winds and severe precipitation is quite conductive to forecasting such weather events.