Modern hydrometeorological observation and forecasting systems are directed to increasing the maximum potential lead time (TWP) for anticipating a hazardous event. For example, the National Weather Service (NWS) weather forecast offices (WFOs) have been equipped with new-generation weather radars (NEXRAD) that provide rapid updates on storm rain-drop reflectivity and rainfall intensity. These and associated WFO observational technologies have enhanced forecasters’ capa- bilities to observe and anticipate movements of severe rainfall events. Hydrometeorological obser- vation and forecasting systems are continuing to advance by incorporating numerical models on storm dynamics and movement. The National Oceanic and Atmospheric Administration’s (NOAA) Hydrometeorological Testbed (HMT) (http://www.esrl.noaa.gov/research/programs/) seeks to dem- onstrate the use of advanced observational and modeling tools on quantitative precipitation estima- tion (QPE) and quantitative precipitation forecasting (QPF) to improve hydrological forecasts and warnings. The HMT is described as a case study below. During pre-event planning, GIS-based databases incorporating flood inundation maps, aerial photographs, and field surveys are used to identify locations where existing properties are threatened