Abstract:With the conventional and intensive observation data and FY-2 satellite products, the mesoscale convective systems (MCSs) that caused th e “7.18" severe heavy rain over Jinan are analyzed. The meso scale convergence center and line played important roles. Furthermore, the severe heavy rain occurr ed near the center of meso scale low pressure and accompanied with them. The ne w cloud clusters which generated behind the right rear of the weakened clouds dev eloped from meso γ to meso β scale. Under enough vapor conditions, they expa nded into compacted α scale clouds with a clear edge that directly caused the se vere heavy rain. The maximum precipitation was strongly related to the lowest TBB measured by FY 2 satellite, therefore, FY-2 satellite products is very impor tant in nowcasting.