Analysis of Two Hail Weather Processes in Northeast Sichuan during Spring and Summer

Using the routine meteorological data,NECP 1°× 1° final-analysis data and the CINRAD/SC Doppler Radar data,the two hail weather processes appearing in northeastern Sichuan have been analysed.The results show that: The two processes with medium to strong vertical wind shear occur in the unstable layer of the upper northwestern airflow and the low layer of warm air which provides the favorable condition for the hail.The height of 0 ℃ and-20 ℃ is the key factor influencing the hail diameter.From the radar analysis, 7.19 hail is a multi-cell storm,and the radar echo structure showed a massive distribution,having weak mesocyclone and echo pendency is not obvious; 4.20 hail echo structure forms hook-shaped,with the characters of echo pendency and mesocyclone structure.