Abstract: In spring there offen remains a layer of cold air above the ground of the east of the Tibetan Plateau after the invasion of cold air in South China.At this time if a trough in the south branch of the westerlies moves eastward over this cold cushion,then there offen appears a trough and frontogenesis in the region surface high.This paper deals with this type of weather process occurred in South China in the months of March to May of 1958-1962.Further the problem of forecasting the precipitation and the thunderstorm activity occurred in this weather process is discussed.