Using the National Water Prediction Service (NWPS) Website to Leverage Flood Inundation Mapping (FIM) Services

The National Weather Service (NWS) recently introduced a cloud-based data visualization and data services website, water.noaa.gov, known as the National Water Prediction Service (NWPS). This March 2024 NWPS release significantly expands the availability of actionable public information for routine and extreme water resources conditions. NWPS, the successor to the Advanced Hydrologic Prediction Service (AHPS), offers a front-end map with user-selectable base maps and data layers. The default data layer features selectable river gauge locations and a new interactive hydrograph ability, allowing users to access river observations and official river forecasts from NWS River Forecast Centers.

In addition to the enhanced display of legacy information on NWPS, new experimental Flood Inundation Mapping (FIM) visualizations are available for approximately 30 percent of the United States population, with full nationwide coverage by 2026. These flood inundation maps depict the extent of water that has overtopped the banks of a river, creek, or stream, based on near-real-time observations and model predictions. Four FIM products are available within the NWPS:

1. National Water Model Latest Analysis Inundation Extent.- represents a snapshot of the latest conditions as derived from the latest NWM analysis.
2. National Water Model 5-Day Maximum Flood Inundation Forecast - based on the NWS National Blend of Models (NBM) forecast precipitation
3. River Forecast Center (RFC) modeled 5-Day Maximum Flood Inundation Forecast - based on RFC forecast precipitation
4. Flood Threshold Inundation - Static categorical FIM (CatFIM) presenting inundation for pre-defined flood category elevations at select NWS river forecast points
   
   

This presentation will describe and demonstrate each FIM product on NWPS in detail and how best to interpret and utilize them for situational awareness and decision support.