Advanced Hydrologic Prediction Service

Created: 7/28/2017 - Updated: 2/27/2020


The Advanced Hydrologic Prediction Service (AHPS) provides a variety of forecasts from the National Weather Service regarding potential magnitude and uncertainty of flood and drought events. The AHPS offers hydrologic forecasts for close to 4,000 locations throughout the United States, and forecasts can be produced from hours to months in advance. The tool mainly draws upon data from the USGS National Streamflow Information Program (, a national network of stream gauges. Users can view information on forecasted flood levels and timing, the probability of a river exceeding minor, moderate, or major flood conditions or exceeding a certain volume, and maps of areas surrounding rivers so that users can identify roads, railways, and other infrastructure that could be affected by flooding. Communities can use the AHPS to be informed about potential flooding and drought risk and impacts, and local officials can use the models to prepare for flood events, evacuate residents, and implement mitigation measures.

Example in use: The NWS partners with other federal and state agencies to map the areal extent of flood categories to create flood inundation maps. These maps display the extent of projected flooding expected to inundate streets, buildings, and other infrastructure using the AHPS forecasts at select locations to help emergency managers and planners assess flood risk. Maps are available for several Southeastern cities, including Birmingham (AL), Greenville-Spartanburg (SC), Jackson (MS), Jacksonville (FL), Lake Charles (LA), Louisville (KY), Newport/Morehead City (NC), Paducah (KY), Peachtree City/Atlanta (GA), Raleigh (NC), Shreveport (LA), Tallahassee (FL), Tampa Bay (FL), and Wilmington (NC).

Phase of Adaptation: Awareness, Assessment, Planning, Implementation


Land managers, natural resource managers, local authorities, planners, scientists, community members


NOAA is an agency that enriches life through science. Our reach goes from the surface of the sun to the depths of the ocean floor as we work to keep citizens informed of the changing environment around them. From daily weather forecasts, severe storm warnings and climate monitoring to fisheries management, coastal restoration and supporting marine commerce, NOAA’s products and services support economic vitality and affect more than one-third of America’s gross domestic product.