Abstract: In this paper a succession of severe local storms occurring in South China on March 4-6, 1980 are analyzed. Moisture channels in the lower troposphere,or Index I for potential convective instability, are found to be related closely with severe local storms. Used to analyze moisture channels and the change in Index I, routine data has some predictability in the forecast of severe local storms, which usually occur in front of maximum moisture flux in the direction of the moisture movement.