Damage survey and mesoscale features analysis on tornado in outer rain-band of typhoon "Mujigae" on 4 October 2015

In the spiral rain-band at the periphery of typhoon "Mujigae" (No.1522), two tornado events occurred on 4 October 2015, and stroke Shunde district, Foshan city and Panyu district, Guangzhou city, Guangdong province, respectively. According to the synergetic analysis of damage survey, network videos and photos, and Doppler weather radar data and so on, the highest intensity of two tornado events is determined to reach EF3 level. We have analyzed the formation and development, damage and meso- and micro-scale features of two typical tornado events with typhoon. Two tornado events occur in the following environment conditions. The tornadoes are located in the right forward quadrant of typhoon "Mujigae". There are mesoscale convergence lines triggered convection in the surface. Water vapor is rich, LCL level is lower, and 0-1km vertical wind shear is strong. Analysis of weather radar data shows that the tornado occurred in Shunde emerges at the apex of hook-shaped echo and the duration of mesocyclone is about 1 hour, while the tornado occurred in Panyu emerges at the break place of bow-shaped echo and the duration of mesocyclone is about 40 minutes. It is shown that mesocyclone scale reduces and its height descends, and radial wind shear strengthens during the period of rapid development of two tornado events. These aforementioned conclusions can be used operationally as the reference in the monitoring and early warning of tornado with Typhoon in China.