Abstract:Based on conventional meteorological observing data, intensive observing data from surface automatic weather stations, Doppler weather radar data in Linyi, wind profiler radar data in Pizhou and ERA5 reanalysis data, this study analyzes the radar characteristics and environmental conditions of the EF2-rated supercell tornado that occurred in the south of Linyi, Shandong on 15 April 2023. The study finds that this tornado occurs behind a bow echo and the parent storm of the tornado exhibits a classic low-level hook echo structure, accompanied by deep mesocyclones and tornadic vortex signatures (TVS). A mesocyclone of moderate intensity forms and develops at the height of about 3 km. When its radius rapidly contracts and its base height rapidly drops below 1 km, the tornado forms. In the early stage of the tornado formation, the environmental conditions are characterized by weak low-level vertical wind shear and strong atmospheric stratification instability. However, as the southwesterly low-level jet rising along the cold pool converges with the northwesterly air current near 700 hPa, a strong vertical wind shear environment forms in the convergence area. The low-level warm and moist jet that rises along the cold pool and is rich in unstable energy, is superimposed with the strong vertical wind shear in the convection triggering area, and with the effect of strong upward motion, the convection is initiated. After the convection is initiated, the transport of abundant unstable energy promotes the rapid intensification of the supercell and ultimately induces the tornado.