Abstract: The data of the monitoring and nowcasting experiment on severe local storms (1984-1986) in Guangzhou region has been analyzed to discuss the conditional probabilities of the occurrence and cover areas of severe local storms lasting several days. It was pointed out that the disastrous weather was resulted mainly from synoptic systems. Moreover, the probabilities for such convective storms on a day varied significantly with whether or not there had been the same occurrence the day before.In terms of the vertical wind shear for the pre-storm environment, the severe local storms were divided into four types in two categories.For each type,we also analyzed the synoptic environment, the static stability indices, the frequency of the occurrence, and the characteristics on satellite imagery. These could provide some ideas and methods to the forecast of severe local storms.