Abstract:The environmental conditions, trigger mechanisms, and Doppler radar echo characteristics of a local strong hailstorm occurred in the central Zhejiang province on 29 May 2013 are analyzed based on the data of NCEP reanalysis, conventional weather observation and regional automatic weather station, lighting and Doppler radar measurements. The results show that the local severe convective weather occurred in the background of the northeast cold vortex; the convective instability of the atmosphere increased while the cold advection in the upper layer moved southward and the warm advection in the lower layer moved northward; the sheer line, cold air, and surface convergence lines were important trigger mechanisms for the severe convective weather while the instability of thermal energy increased, at the same time; the convergence line of the surface also played the role of organizing strong convection. The higher potential vorticity in the isentropic surface contributed to the genesis and development of the super cell storm. The revised sounding data indicate that it is favorable for local hailstorm weather happened when the strong potential instability， moderate vertical wind shear, and sufficient water vapor in the lower layer appeared with a higher height of the 0 ℃ layer in early summer. The warm moist air in the lower layer flowed into the updraft area by the increased flow suction effect, and accelerated, leading to the ground wind generation. The super cell storm was formed, resulted from the organized multiple strong convective echo centers by a meso cyclone, inducing the local severe hailstorm weather.
