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National Water Prediction Service (NWPS) River Gauge Observations/Forecasts and Flood Outlooks

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NOAA National Weather Service's National Water Prediction Service (NWPS)

The National Weather Service (NWS) National Water Prediction Service (NWPS) provides short-term observed and climatic trends of precipitation, river stage observations and forecasts, and long-range river flood outlooks across the lower 48 United States (CONUS), Puerto Rico, and Alaska. The NWPS river stage observation and forecast products and long-range river flood outlooks display the magnitude and uncertainty of occurrence of floods or droughts, from hours to days and months, in advance. 

The majority of the observed water level data displayed on the NWPS web pages originates from the U.S. Geological Survey (USGS) National Streamflow Information Program, which maintains a national network of streamgages. In addition, real-time water level information is collected from other federal, state, and local streamgage networks.

In March 2024, the NWPS replaced the NWS Advanced Hydrologic Prediction Service (AHPS) as the primary source for NWS water prediction information.

Interactive Map: River Stage Forecast

Maximum Forecast Flood Category

How to

View the User's Guide to the National Water Prediction Service (NWPS).

  • On the interactive NWPS map, under “River Gauge,” users can select “observations and forecasts” or the “long range flood outlook.”
  • When “observations & forecasts” is selected, check the boxes next to each flood category to display or hide them on the map. 
    • Gauge location icons now have both observed and forecast (where available) status shown in relation to flood category; observed status is the circle, while forecast is the surrounding square.
  • When “long range flood outlook” is selected, a dropdown menu allows you to choose the percent chance of exceeding river flood levels to display, from 5% to 95%. Then, use the checkboxes to select the flood categories you’d like to display.
  • Hover over a point on the map to view a hydrograph for that river gauge location. The first click of a map icon brings up a robust hydrograph popup display, while a second click brings you to a full hydrograph page. Features include: 
    • Upstream/downstream hydrographs available in a single click.
    • Listings of metadata, crest histories, local impacts, probabilistic info, and gage photos remain from AHPS.
    • Separate National Water Model (NWM) display tab allows you to view NWM flow guidance over different time scales (ie. short, medium, long-range) and ensemble analysis. 
    • The supplemental “National Water Model Guidance” hydrograph displays the NWM model output in addition to the official hydrograph. the details about each details about NWPS and how it was developed.
  • Users can also adjust the basemap in the “Map” dropdown, add administrative boundaries, and view precipitation data alongside other NWPS datasets (e.g., river stage observations and forecasts).