The National Water Model (NWM) is a water resources model that simulates and forecasts water budget variables, including snowpack, evapotranspiration, soil moisture and streamflow, over the entire continental United States (CONUS). The model, launched in August 2016, is designed to improve the ability of NOAA to meet the needs of its stakeholders (forecasters, emergency managers, reservoir operators, first responders, recreationists, farmers, barge operators, and ecosystem and floodplain managers) by providing expanded accuracy, detail, and frequency of water information. It is operated by NOAA’s Office of Water Prediction.
Learn more about the National Water Model: http://water.noaa.gov/
The NWM Short Range Forecast is stored in the noaa-nwm-pds Amazon S3 bucket in the us-east-1 AWS region.
This bucket contains a four-week roll over of the Short Range Forecast model output and the corresponding forcing data for version 1.2 of the NWM model. The model is forced with meteorological data from the High Resolution Rapid Refresh (HRRR) and the Rapid Refresh (RAP) models. The Short Range Forecast configuration cycles hourly and produces hourly deterministic forecasts of streamflow and hydrologic states out to 18 hours.
All data is in Network Common Data Form format (NetCDF) and correspond to these general configurations:
The data is organized by daily forecast, each forecast begins with the
prefix nwm.yyyymmdd
, where: - yyyy
: year - mm
: month - dd
: day
of the month
For example, all forecast data for 3 May 2018 have the prefix
nwm.20180503
, you can use the AWS Command Line Interface to list this
forecast data. For example:
aws s3 ls noaa-nwm-pds/nwm.20180503/ --no-sign-request
For each daily forecast, the forcing data are separated from the short
range forecast data using the prefixes
nwm.yyyymmdd/forcing_short_range/
and wm.yyyymmdd/short_range/
.
Each data file uses the following naming convention:
nwm.tHHz.shortrange.FILENAME.f0CYCLE.conus.nc
Where: - nwm
= national water model (this is the same for all files) -
tHHZ
= hour when the forecast was made, for example t00z for midnight
- shortrange
= shortrange forecast (fixed) - FILENAME
= see list and
table below - f0CYCLE
= the cycle of the forecast up to 18 hours, for
example 9th hour would be f009 - conus
= continental United States
(this is the same for all files) - nc
= NetCDF file format (this is
the same for all files)
For example, to retrieve the forecast made at midnight on a particular date for reservoir water surface elevation at the 8th hour from midnight, you would construct the following file name:
nwm.t00z.short_range.reservoir.f008.conus.nc
Which you could then attach to one of the following paths:
s3://noaa-nwm-pds/nwm.yyyymmdd/short_range/
(replace yyyymmdd with the
date of interest)
or to a https url constructed like this:
https://noaa-nwm-pds.s3.amazonaws.com/nwm.yyyymmdd/short_range/
(replace yyyymmdd with the date of interest)
Each day is made up of hourly forecasts and each forecast has a time horizon out to 18 hours. The data is made up of four forecast files and a forcing file iterated over the forecast and horizon times. These files are in NetCDF format and contain within them metadata describing their content.
Listed here are some of the parameters and properties of the respective files (by filename element). More details are available in the metadata contained within each file:
forcing: Geospatial, 1Km Gridded NetCDF
land: Geospatial, 1Km Gridded NetCDF
terrain_rt: Geospatial, 250m Gridded NetCDF
channel_rt: Point type
reservoir: Point Type
Contained in the table below is a summary of the files and examples of path and filenames.
File Name Description Cycle Example File Name
forcing Forcing paramters for the NWM model 1 Hr /short_range/nwm.t00z.short_range.forcing.f001.conus.nc land Snow cover, Near Surface Soil Moisture 1 Hr /short_range/nwm.t00z.short_range.land.f001.conus.nc terrain_rt Ponded Water and Water Table Depth 1 Hr /short_range/nwm.t00z.short_range.terrain_rt.f001.conus.nc channel_rt Stream Flow and Stream Velocity 1 Hr /short_range/nwm.t00z.short_range.channel_rt.f001.conus.nc reservoir Water Surface Elevation, Reservoir in and out flow 1 Hr /short_range/nwm.t00z.short_range.reservoir.f001.conus.nc
27th July 2018. Corrected the units of the following paramters: - ACCET - from m to mm - qBucket - from m\^3\^ to m3 s-1 - qSfcLatRunoff - from m\^3\^ to m3 s-1
Please note that the metadata in the corresponding netCDF files may have incorrect units for: - qBucket and qSfcLatRunoff.
The units listed above are the correct units.