It is difficult to isolate aerosol effects on clouds because of the complicated microphysical, dynamical, and chemical feedbacks that occur. Cloud kinematics (particularly, updraft velocity) have been previously used to represent meteorological effects on clouds, but their impact is poorly understood. To avoid complications and ambiguity, the synoptic meteorology of the Great Plain regions was investigated here. The RACORO fair weather cumuli days were grouped into five different categories according to the airmass source regions and meteorological characteristics. The relationship between aerosol and cloud properties was separately investigated for each category. Therefore, the influence of the synoptic / mesoscale meteorological conditions on the cloud macrophysical / microphysical properties was examined by assessing the relative importance of the effect of varying aerosol concentrations.