Analysis of Environmental Conditions and Tornado Storm Features of Two Tornadoes in Jiangsu during the Meiyu Period in 2020

In June and July of 2020, two tornadoes occurred in Jiangsu Province, which were located in Gaoyou on 12 June and Suqian, Lianyungang and Yancheng on 22 July, respectively. The property in the above areas was damaged, and no one was killed.We use observation and reanalysis data to compare and analyze the weather background and convective environmental conditions that produced the two tornadoes in this paper. The radar echo shows that the characteristics of the convection system that produced the two tornadoes are signif icantly diff erent: On June 12, there was a discrete unit independent of the echo of the main rainband, which produced a tornado in Gaoyou City and lasted a long time; while on July 22, the unit that produced the tornado was inlaid at the southern end of the main rain belt echo, it moved leaps and bounds in the life history, aff ecting several nearby counties. The both tornadoes occurred in the regions and seasons where tornadoes occur most in eastern China, and the synoptic-scale backgrounds are typical rainstorm circulation during the Meiyu period. The mesoscale convective systems that produce the tornados occur in the high-low-level jet coupling area on the south side of the ground warm front. The difference is that the previous system was stable and less moving, and the latter developed more rapidly and intensely. From the perspective of convective environmental conditions, both processes have moderate to strong CAPE, better low-level humidity conditions and large low-level vertical wind shear that are conducive to the occurrence of tornadoes, especially the conditions on July 22 are more favorable, with lower lifting condensation level of 105m and stronger 0-1 km and 0-6 km vertical wind shear of 11 m/s and 26 m/s, respectively.