**Abstract**

Precipitation is the main driver of the hydrological cycle, and therefore, the measurement and forecasting of precipitation is a key element in hydrological and meteorological applications such as rainfall-runoff modeling, precipitation forecasting, flood forecasting, flood risk management, and hydrological and climate studies. Flooding is one of the most vulnerable natural hazards in the world. It has vast impacts, including loss of life, damage to property and goods, and negative health, social and economic impacts. Reliable and accurate meteorological and hydrological forecasting is therefore a major priority to minimize such impacts. Significant progress has been made to improve the forecasting of extreme rainfall events for flood prediction in large rural catchments. However, accurate, reliable, and timely flood forecasting in urban areas is a challenging task that it is now crucial for the reduction of hazard and the preservation of life and property. This chapter discusses some of the latest advances in the measurement and forecasting of precipitation with weather radars, including applications for river catchments and small urban areas.

**Keywords:** weather radar, rainfall, flooding, nowcasting, hydrological forecasting, polarimetric radar
