Abstract: The circulation situation and meteorological features of a strong convection process occurring in Hunan province is analyzed from April3—4,2015,using conventional observation data such as ground and high altitude.The high-resolution WRF model focuses on the strong combination of northeastern Hunan.The convective weather is numerically simulated,and the structure,evolution and trigger mechanism of the strong convective storm under the complex underlying surface of the Dongting lake area are discussed.The results show that this is a mixed strong convective weather in a typical low-level warm-flow forced weather background.The4 hPa up-and-down of ground pressure corresponds to different types of severe convective weather in northeastern Hunan.The continuous strong vertical wind shear and updraft the effect is to maintain the storm,and the convective monomer merges and develops to strengthen the multi-cell strong storm (the supercell storm).The unstable energy accumulation in the northeastern part of Hunan,the local geothermal convection and topography and other uplifting effects,and the low-level flow field sharply merge into a strong rotational rise.The movement triggers the release of unstable energy,which provides favorable dynamic and thermal instability conditions for strong convective weather such as hail,thunderstorm and heavy rain.The simulation results accurately describe the spatial structure and environment of the mixed strong storm in the Dongting lake area.The evolution of parameters has a certain indication for the early warning and forecasting of mixed strong convective weather.

Key words: severe convective weather, underlying surface features, numerical simulation, Hunan province