Abstract: Persistent severe rainfall (PSR) and its related phenomena lead to considerable threats to human safety and economic stability. Thereby, prolonging the forecast range would be of great importance to enhance our disaster prevention and mitigation capabilities. With in-depth understanding of the formation mechanisms for PSR events and the medium-term dynamic forecast methodology in the regional model, a set of improved methods for the medium-term dynamic forecasting of PSP events using the regional Weather Research and Forecasting (WRF) model is summarized with the aim to reduce errors in initial condition, lateral boundary condition and regional model interior forecasting. For the lateral boundary condition, the low-pass filtering method is applied to enable better forecasting of circulation fields and precipitation at lead times above 5 days. For the regional model interior forecasting, the use of spectral nudging leads to obvious improvements in the forecast of precipitation in the categories above light rain at lead times of 3-7 days. For the initial condition, the update of initial condition is an effective method to retain the large-scale forecast of the global model prediction and the small-scale features of the WRF forecasts. Results of 15-day forecasts using the WRF indicate that the update of initial condition significantly improve the forecast of accumulative precipitation above 50 and 100 mm.