Observational Analysis of Supercells in Landfalling TC Yagi in 2018

In 2018, Typhoon Yagi made landfall in east China, and spawned 11 tornadoes thereafter, which was the first, and the only one till now, tornado outbreak in China. This work examines the characteristics of all the supercells that formed during the period when six of the 11 tornadoes were generated by Yagi when it entered Shandong province. A total of 15 mini-supercells were detected during this period, among which 5 mini-supercells were tornadic. A comparison of the characteristics of tornadic mini-supercells with non-tornadic mini-supercells suggests that tornadic mini-supercells were generally stronger and lasted longer than non-tornadic supercells. Some certain tornadic mini-supercells were weaker and lasted shorter than most non-tornadic mini-supercells. The intensity of the parent mini-supercell increased sharply before tornadogenesis. Tornadic mini-supercells’ mesocyclones were found to be generally higher and thicker than non-tornadic mini-supercells’ mesocyclones. Interestingly, our results showed that the nearer the tornadic mini-supercells is from the center of TC, the stronger and longer-lasting the tornadic mini-supercells (among all the tornadic mini-supercells recorded) is. In addition, the strongest mini-supercell had quite complex structure with several mesocyclones at the same time and cyclone replacement. Examinations on the features of all the mini-supercells in the whole path of typhoon’ Yaji and a comparison with the general features of mini-supercells in Hurricane Ivan (2004) in the U.S., which produced 118 tornadoes, are also ongoing.