The Weather Research and Forecast (WRF) model is the next-generation model and assimilation system being developed by a broad community of government and university researchers. Its use will advance both the understanding and prediction of important mesoscale weather, particularly at the 1-10 km scale. The WRF framework can also be applied for studying regional climate processes, including those associated with widespread and heavy precipitation with serious hydrologic consequences. This paper presents the first regional climate application using the WRF version 1.1 with a horizontal grid spacing of 30 km for an integration period of 3 months. The simulation focuses on the flood-producing heavy rainfall that occurred in the summer of 1993 over the central U.S. Sensitivity experiments are conducted to study the impacts of microphysics representation. Intercomparsions between various microphysics schemes used in the WRF and MM5 (fifth-generation PSU/NCAR mesoscale modeling system version 3.3) are performed to identify an appropriate physics configuration that realistically simulates the regional precipitation anomalies. We will discuss new development needed within the WRF framework for improving regional climate modeling applications.