The severe tropical storm "Kammuri" brought severe disaster to southern Fujian and eastern Guangdong.Based on the synoptic situation,T213 numerical weather prediction product and local meteorological data,the severe tropical storm "Kammuri" are analyzed synthetically.The results indicate that the adjustment of steering flow and the air pumping action of upper divergence field resulted in the storm strengthening and the path changing.The conditions that the torrential rain took place and sustained at the tail of "Kammuri" include the low-level south-west jet stream,the continuous water vapor transportation,the strong upward vertical movement,and the extreme instability of atmospheric stratification.