Previous studies of convective activity over northern and central California were based on data from scattered weather reporting stations. Radar, however, by maintaining a large area under constant surveillance, displays a more complete picture of convective cell formation and patterns. With the installation of the WSR-57 radar in Sacramento, Calif. in early 1960, the opportunity to study the formation and patterns of convective cells over northern and central California was made available. This article summarizes the findings of such a study for the summer months of 1960 and 1961.