Abstract:Fiftyone physical parameters are calculated by using upper sounding data from the Xuzhou, Sheyang and Nanjing Stations from June to August in 2004-2013. Based on the significance test of the correlation coefficient between physical parameters and flashheavyrain events (flash heavy rain that occurred after 0-6 h of the observation time) and the analysis of numerical distribution of physical parameters in the flashheavyrain samples and the nonflashheavyrain samples, 16 physical parameters of prediction are selected finally. Through analyzing the indication to the flashheavyrain events of different types of physical parameters, and according to the different threshold of physical parameters in each month, different criteria for the flashheavyrain events are determined respectively. 〖JP2〗Thus, the flashheavyrain〖JP〗 forecast model for summer shorttime heavy rains in Jiangsu is established by the membership function conversion method. The fitting test and forecasting test of the forecast model are verified, and the results are good.