This case study investigates the interactions between the atmospheric boundary layer and the land-surface using the Oregon State University (OSU) Coupled Atmospheric Boundary Layer - Plant - Soil (CAPS) model. Simulations are made using the data set for 31 May 1978 available from Cabauw, Netherlands for model initialization and verification. We first make simulations of the land-surface forced by observed atmospheric conditions, followed by the atmospheric boundary layer (ABL) forced by observed surface fluxes. These 'stand-alone' tests allow us to isolate processes responsible for surface fluxes (land-surface scheme without ABL interaction), and boundary-layer development (ABL scheme without land-surface interaction) before attempting to couple the two schemes. In a coupled mode, more complicated interactions and feedbacks are possible, including the formation and interaction with ABL clouds. Results indicate that in coupled land-surface/ABL simulations, realistic daytime surface fluxes and atmospheric profiles are produced using the OSU CAPS model with updated model parameterizations. ABL clouds are found to be particularly sensitive to the prescribed large-scale vertical velocity. Updated model parameterizations include a modified boundary-layer depth formulation in the ABL scheme, and changes in the soil heat flux calculation, soil hydraulic and thermal properties, and soil layering and plant root density in the land-surface scheme. This day has a large atmospheric demand (high potential evaporation), with daytime drying of the upper soil layers (higher root density) corresponding to a decrease in transpiration after noon because soil moisture cannot be replenished from soil layers below at a rate to maintain high evaporation. Below the direct influence of transpiration, movement of soil moisture upward from the subroot zone is necessary to 'recharge' upper soil layers, and can be sensitive to the choice of the soil layering and hydraulic parameterization.