In this study, we use Ultra-Parameterization (UP), a large-eddy permitting climate model based on SPCAM, to investigate the interaction between aerosols and clouds in the present-day climate. UP’s advantage is its ability to explicitly capture the scales of large-eddies in the boundary layer, strong inversions, and low-clouds in the atmospheric boundary layer. The model also better captures the vertical turbulence structure, which is crucial for accurately capturing cloud drop activation. We present how variations in aerosols and meteorology covary to influence cloud properties in UP and compare their sensitivities to those seen in the standard SPCAM model. Furthermore, we investigate the extent to which UP captures finescale features such as pockets of open cells, which are regions of open cellular convection surrounded by closed-cellular convection driven by strong aerosol-cloud-precipitation interactions, and ultraclean layers in the boundary layer with cloud condensation nuclei concentrations <10 cm-3 towards an attempt to assess whether differences in present-day and pre-industrial emissions can lead to changes in their relative occurrence.