This presentation describes the rapid prototype development of an inaugural capability for an Integrated Coastal Observation and Flood Warning System (ICOFWS), initially focused within the tidal Potomac River. A collaboration of the Virginia Institute of Marine Science (VIMS), NOAA National Weather Service (NWS) Forecast Offices in Wakefield and Sterling, Virginia, and Mitretek Systems developed the capability for a VIMS high-resolution hydrodynamic storm-surge model, coupled with the newest generation NWS Weather Research and Forecast model and high resolution digital elevation LIDAR data, to predict land inundation from storm events in the Washington metropolitan area and the tidal Potomac River. This prototype capability then uses emerging Geographic Information Systems (GIS) visualization technologies to present forecast information in a manner that can be integrated into operations systems of local jurisdiction emergency managers and other planners. Initial steps have been taken to document a proposed process to bring this capability into operational status within the standard NWS forecast cycle as a forecast tool. This prototype model and associated visualization are being explored for use by partners within the Integrated Ocean Observing System (IOOS) Mid-Atlantic Coastal Ocean Observing Regional Association (MACOORA) to demonstrate interaction of organizations operating in, and providing support within, the Chesapeake Bay region, as well as potential use of this collaborative procedure within other IOOS regional associations throughout the United States. This focused systems engineering approach allows for the more-rapid-than-typical development of prototype systems that can be evaluated for use within the broader IOOS and Global Earth Observation System of Systems (GEOSS) to provide more timely support to those responsible for preparing for, and reacting to, environmental effects on critical infrastructure and our society.