Abstract:Mesoscale convective analysis plays an important role in short term severe convective weather forecasting. In this paper, the mesoscale nowcasting analysis and its related techniques being used in the National Meteorological Centre (NMC) are presented. The mesoscale nowcasting analysis is the second part of Mesoscale Analysed Technical Specification. A comprehensive analysis method combined with subjective nowcasting techniques and objective algorithm based on CMA Severe Weather Automatic Nowcasting system (SWAN) is used. The techniques of severe convective weather monitoring, and objective analyzing method of automatic observation station are also introduced. Taking the convective weather that occurred on 17 April 2011 as an example, we show how to quickly identify and acquire the actual severe convective weather events such as short time severe precipitation, wind gusts, thunderstorm, hail and tornadoes, analyze the types and structural characteristics of the ongoing mesoscale convective system, judge the favorable mesoscale environments for the future development of the convective system and apply the objective identification, tracking and extrapolation products based on radar and satellite data, so as to guide the convective nowcasting in 0-6 h period. Tests in NMC show that the mesoscale nowcasting analysis can provide reliable references for severe convective weather nowcasting.