Aviso is our flood warning decision support system. It was developed by us to meet the specialized needs of flood warning--needs that cannot be met with commercial-off-the-shelf software. It integrates public-domain software from government agencies, software from vendors, and software developed by our staff. It is provided to our clients as a part of our engineering services. Aviso includes the following applications, which can be used separately or in an integrated manner: Aviso FS. This Aviso component (formerly known as CFS--Catchment Forecasting System) makes site specific forecasts of future flows and stages for threat recognition. The standard version of Aviso FS includes software programs HEC-1F and UNET from the Corps of Engineers. However, the advantage of Aviso FS over similar packages available from others is that it can be tailored to use watershed and channel models available to our clients. For example, in Fort Collins, CO, we configured Aviso FS to use the EPA's SWMM program, HEC-2, and HEC-RAS. Aviso Watch. Timely threat recognition is critical if flood warning lead time is to be maximized. An automated system speeds recognition by using threat recognition rules with expert system technology to identify conditions that indicate a flood threat. Aviso Watch works with ALERT data collection systems to identify flood threats and to disseminate information, using triggers or thresholds for rainfall, water level, or other environmental states. Aviso Watch can also be integrated with Aviso FS to permit anticipation of future threats. Aviso Watch includes simple notification options; it can also be integrated with a variety of commercial-off-the-shelf notification programs. Aviso Mapper. This component yields maps of potentially-inundated area in near-real time, using observed and forecasted water levels. Map creation and display can be on-line, with models executed in real-time, or it can be off-line, with models executed before a storm, and maps stored in a digital atlas.