Abstract: Two thunderstorm gale processes happening in Hubei province on May 23 and August 18,2013,called "523" and "818" processes,respectively were analyzed.The thunderstorm gales were investigated through analysis of the weather situation,vertical structure,physical parameters of the atmosphere and Doppler radar echo using conventional weather,NCEP (National Centers for Environmental Prediction) reanalysis and radar data.The results indicate that the "523" process is a typical supercell forming at Shiyan region under the condition of high altitude cold trough shifting eastward.The "818" process is a severe convection result due to the combined interaction between unstable conditions and weak cold air at the surface under the influence of a subtropical high outside northeastern airflow and a landing typhoon.The atmospheric parameters of the two processes have some similarities with a high value in CAPE (Convective Available Potential Energy) (>1 300 J·kg^-1),a dry adiabatic decreasing condition in the lower level,and a poor water vapor condition in the entire level.The vertical distribution of θ_se shows that there is an invading dry air in the mid-low level during the two weather processes.Some convection parameters,such as K index and vertical wind shear,show a significant difference between the two processes.It reveals the complexity and uncertainty to predict atmosphere parameters of a thunderstorm gale weather.The main radar echo characteristics in the "523" process include mesocyclone,hook echo,‘V’ notch and echo pendency.Those in the "818" process include gust front,bow echo,and echo center quickly dropping to the ground.A typical mid-altitude radial convergence and areas of large gale speed value are also observed in the two processes.These radar echo characteristics,such as Mesocyclone,hook echo,gust front,mid-altitude radial convergence,are good indicators for the forecasting of a thunderstorm gale.

Key words: Thunderstorm gale, Convection parameter, Supercell, Gust fronts