A non-hydrostatic, mesoscale model, LOCALS, is used to investigate the effect of land surface changes on precipitation in an urban area. The horizontal mesh used in the model is approximately 5 km and the domain includes Tokyo and central Japan. Land surfaces identified as pavement or urban are transformed into forested land and model simulations are performed for both the current urban land surface and the hypothetical forested land surface. Detailed analysis is performed for two sample cases. On 5 August 2003, increased heating by the urban surfaces increases the height of the urban boundary layer resulting in much more rainfall. On 25 July 2001, air that is advected over Tokyo but forms a precipitating cloud away from the urban core carries less moisture and therefore produces less rainfall. These case studies suggest that changes to land surface types in urban areas may increase or decrease rainfall in the urban area and further research is necessary before it is possible to generalize these results.