Abstract:Using the data of conventional observation, mesoscale automatic station and new generation monostation radar, and networking and mosaic products, FY 2C infrared images and 6 h NCEP reanalysis data, mesoanalysis was taken on the process of widespread hail in Taizhou of Zhejiang on 19 March 2014. The results show that: (1) According to the analysis of environmental field conditions and the corrected sounding data, the lower wet and upper dry structure in Taizhou was unstable. In the situation of increased ground temperature and convective available potential energy and relatively large vertical wind shear at 0-3 km and 0-6 km after noon, wetness was conductive to the formation of severe convective weather such as the gale and hail. (2) According to the movement and evolution of cold front that triggered the movement of synoptic scale convective system, the whole process could be divided into four stages, and the thunderstorm, gale and widespread hail appeared in the third stage. (3) The mature stage could be divided into three stages of squall line formation, bow echo and outbreak of hailstorm cells due to the echo forms of the system, which revealed the significantly different element characteristics in the automatic station elements and radar products compared to other stages. (4) The abundant vapor in the near surface layer, lower lifting condensation level, southern oscillation of southern branch trough and northern transverse trough, systematic lifting on the left of upper level jet stream exit area, and triggering of cold front near surface, mesoscale convergence line and landform were the main causes for the enhanced outbreak of squall system in Taizhou, leading to hail weather with gale. (5) Forecasters make full use of timeliness advantages of automatic stations, carrying out the correction of mesoanalysis work can effectively improve the quality of nowcasting.