Most previous studies of frontogenesis in the atmosphere have neglected the effects of moisture and the adiabatic heating effects associated with condensation and evaporation. The research in this thesis investigates the effects of condensation and evaporation on mesoscale frontal circulations in a two-dimensional numerical model. Utilizing an explicit prediction scheme for the prediction of water vapor, cloud water, and rainwater, the model is used to investigate the interactions between convection and the larger-scale environment. The model results are qualitatively compared with recent observations from the SESAME-AVE (Severe Environmental Storms and Mesoscale Experiment - Atmospheric Variability Experiment) experiment. Diagnostic calculations, based on the Sawyer-Eliassen secondary circulation equations, determine the contributions to the frontogenesis by different physical mechanisms. In the frontal simulations, the effects of condensation produce a much stronger front compared to a dry simulation. The model with the explicit scheme simulates some realistic features observed in the atmosphere. The mechanisms for the formation of different rainbands are studied from the numerical simulations. The hourly output from the numerical model is used to compute the heat, moisture, and kinetic energy budgets. It is found that the latent heat released is the most important term in the heat and moisture budgets for the two-dimensional frontal circulations. Different schemes for calculating the effects of convection are also tested. The details of convection in the fine-grid ((DELTA)x = 40 km) simulations do not affect the frontal circulation significantly. For the coarse-grid ((DELTA)x = 200 km) simulations, the convective heating distribution is significantly affected by the PBL processes.
