The NOAA National Water Model provides current conditions and short, medium and long range hydrologic forecasts across the US. Stream discharge and velocity are forecast on National Hydrography medium resolution streams, land surface variables on a 1 km grid, and reservoir inflow and outflow at modeled reservoirs. National water model forecasts are only available for a short period (about 72 hours) from NOAA. HydroShare is archiving forecasts for longer (2-3 weeks) and assimilated current conditions indefinitely. The National Water Model Forecast Viewer app provides access to the data archived in HydroShare. This app lets you graph and download National Water Model forecasts and current conditions for individual stream reaches, land grid cells and reservoirs, or for a set of these within a watershed.
What can I use this App for?
To graph and download time series of National Water Model forecasts and current conditions. You can choose the place (stream, grid cell or reservoir) where you want the forecast by clicking on a map or entering the unique identifier (COMID). Then you can set the type of forecast, time and variable you want and graph or download it. You can also access forecast time series in WaterML format, a standard XML format developed by the CUAHSI Hydrologic Information System, which while not very friendly to the human reader is designed for automated computer to computer web service information exchange so you could write programs to access this data automatically.
Story map documentation
An online ESRI story map presentation gives information on how to use this app.
- The Channel dataset shown on the map depicts the medium resolution National Hydrography Dataset streams for the U.S. Each has a unique identifier (COMID). Clicking on a stream segment in the map shows the COMID and enters this in the data entry panel on the left, where you can select other parameters and click submit to graph the selected forecast. Streamflow and velocity are available for each stream segment.
- The Land Dataset provides surface forecast variables over a 1 km grid. Select Geometrh land in the data entry panel on the left to show the grid on the map. Click on a grid cell to enter its coordinates in the data entry panel. Forecast variables available to retrieve include Snow Depth, Snow Water Equivalent, Snow-cover, Accumulated Total ET (Evapotranspiration), Near Surface Soil Saturation, and Average Snow Temperature. Refer to National Water Model and WRF-Hydro documentation to learn precisely what these variables are.
- The Reservoir Dataset provides streamflow forecasts for major U.S. reservoirs. Forecast variables available include Inflow and Outflow.
Example use of the app
The menu bar on the left hand side allows the user to choose from a series of National Hydrography datasets, output variable, and forecast parameters. The image on the right shows streamflow forecast for short range, medium range, and long range forecasts, as well as, analysis and assimilation. Hydrologic variable selection is dependent on the selected datasets. After the desired options are selected, the submit button generates a graph of the forecast.
Within the menu options, shown as the three horizontal bars, users may save an image of the graph or extract the data in tabulated format. In addition, Get WaterML at the bottom gives the data in WaterML format.
This app includes an application programing interface (API) that supports automated access to the outputs to this app from other computer programs. If you are a computer program developer this information will be useful to you, but for others it is technical detail you can skip. The API uses URL style address that can be adjusted to view a specific forecast without having to select each item in the menu.
The desired inputs are shown here:
Forecast: Short Range
Geometry: Channel Dataset
Start Date: 2016-09-25
Time: 1:00 PM
The API is the address below, the selected inputs are shown in bold:
(Please keep in mind that the forecasts are only stored for two weeks so the the above address will not show any data, change the date to a time within the last two weeks to view actual data)
Any of the selections in the menu for the NWM can be used in the API to programatically access the data. A more in depth view of using the API and all of the variable names can be found by going to: