To understand the climatic impact of continental boundary-layer cloudiness, it is important to study the basic physical processes that are related to the formation, development and dissipation of these clouds. In this study, the data collected from the Atmospheric Radiation Measurement (ARM) site in the Southern Great Plains (SGP), combined with the Regional Atmospheric Modeling System (RAMS) developed by Colorado State University, are used to study the sensitivity of the land-surface hydrological processes on simulation of boundary-layer clouds. The boundary layer features and surface fluxes of the daytime and nighttime boundary-layer for stratocumulus are analyzed at the sites from which radiosondes were released. The model is initialized with five local soundings, surface meteorological data as well as local land use data. The simulated clouds are then compared with ARM observations from the Belfort ceilometer, the Micro-Pulse Lidar (low resolution) and with calculated LCL values obtained through surface meteorological data. Comparisons between observations and model predictions show a good qualitative agreement not only for the main features of the boundary layer but also for the macro physical properties of the boundary layer clouds. The model simulation shows that the development of boundary layer clouds is very sensitive to soil moisture content. To demonstrate the significant role of boundary-layer clouds on the regional climate, we also design the numerical simulations (one month run)to examine feed backs between boundary-layer clouds and the environment