Analysis of a Tornado Process in Eastern Guangdong at the Periphery of a Typhoon
In order to explore the cause of an EF2-strong tornado in Jiedong District of Jieyang City un-der the influence of the peripheral circulation of Typhoon Lionrock(2117),the tornado process was analyzed by the ERA5 reanalysis data,conventional meteorological observation data and S-band Doppler weather radar observation data in Shantou.The results show that the tornado appeared in the southeast jet stream between Typhoon Lionrock and the subtropical high,accompanied by the continuous transport of energy and water va-por.About 725 km away from the typhoon center,the tornado occurred before the typhoon landed at the in-tensity of tropical storm.The low uplift condensation height,strong 0-1 km vertical wind shear and large storm relative helicity were conducive to the occurrence of and development of the tornado parent storm.Be-fore the tornado,a convergence line near the ground moved north obviously,and the tornado occurred at the convergence center.When the tornado passed through,the wind speed and direction had a sudden change as observed by automatic weather stations near the path,along with a temperature drop,but the short-term heavy precipitation only appeared on the southwest side of the path.It can be seen from the radar character-istics that the tornado parent storm was characterized by a low-level inflow gap and a middle-level overhang echo,and had a low mass core typical of typhoon-induced tornado parent storm.Two continuous volumetric scans of tornadic vortex signature(TVS)can be used to warn of tornadoes in certain amount of advance.
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