Skip Navigation Links 
NOAA logo - Click to go to the NOAA homepage National Weather Service   NWS logo - Click to go to the NWS homepage
Environmental Modeling Center

Local forecast by
"City, St" or Zip Code


NOAA Wave Watch III logo Click here for the MMAB home page

WAVEWATCH III Model Data Access


The EMC WAVEWATCH III® global wave model Multi-1 was decommissioned in NCEP operations on March 22, 2021. It has been replaced by a new configuration of the WAVEWATCH III global wave model, called GFS-Wave, and coupled to the Global Forecast System (GFSv16), as part of the Unified Forecast System.


It is being maintained for archival and verification purposes only.

Here are the details (PDF) on how this will affect users of this site.

Output of the new GFS-Wave model is available on NOMADS and Production FTP

*under gfs.YYYYMMDD/CC/wave/gridded and gfs.YYYYMMDD/CC/wave/station

Graphics of the GFS-Wave model output will become available some time in April on the Model Analysis and Guidance (MAG) site. Note that the current WW3 link on that page is to a preliminary set of GFS-Wave graphics. New graphics with more options will be added with the coming update in May, and will be under GFS-Wave instead of WW3.

NOTICE: The Global Wave Ensemble System (GWES) was discontinued on 23 Sep 2020 and has been replaced by an improved GEFS-Waves, consisting of a one-way nesting of the WAVEWATCH III system with the recently upgraded GFS Ensemble Forecast System. The NOAA press release on the upgrade is here, and information on GEFS is available here.

The GEFSv12 Service Change Notice (issued 8/20/2020, PDF) is here, and you can find information on the evaluation of the GEFS-Waves portion of the GEFS system in the Model Evaluation Group (MEG) Summary page on the GEFSv12 upgrade here.

The model data is available four times a day (0, 6, 12, 18)Z from:
  • Production FTP (gefs.YYYYMMDD -->cycle-->waves)
  • NOMADS (Ocean Models-->GFS Ensemble Wave-->(grib filter or https file download).
Details on the products can be found here (scroll down to GEFS - Wave - Global).

Model data from the latest WAVEWATCH III runs is available in GRIB (GRIdded Binary) format on the Marine Modeling and Analyses Branch FTP server, the NCEP NOMADS GDS/DODS data server, and the NCEP Central Operations Production FTP server, at the following URLs:

  • Current Data (WAVEWATCH III multigrid latest version)
    1. FTPPRD (NCO Production FTP Server, today and three days prior.)
    2. MMAB FTP (Marine Branch FTP server, last six runs)
    3. NOMADS via (OpenDAP) (last seven runs)

  • Current Data (WAVEWATCH III version 2.22 grids)
    1. MMAB FTP (Marine Branch FTP server, last seven runs)

  • Current Data (WAVEWATCH III ensemble)
    1. MMAB FTP (Marine Branch FTP server, today and three days prior)

  • Archived Data (WAVEWATCH III version 2.22 Hindcast reanalysis)
    1. MMAB FTP (Marine Branch FTP server, Aug 1999 to present)

Notes and Information on Using WAVEWATCH III Model Data


The operational data file format is GRiB (GRIdded Binary). Additional information on the use of GRiB at NCEP is available here.

To work with WAVEWATCH III GRiB, any standard tools which read GRiB will work. One such tool is the freely available wgrib utility. The wgrib home page and software is here.

Another free GRiB file reader is the read_grib utility that can decode GRiB data directly into MATLAB (MATLAB is a registered trademark of The Mathworks, Inc.).

Note: A new version of getgrib.m is now available from the MMAB FTP server. This new version decodes the NWW3 latitude and longitude vectors from the GRiB header. You can get it here.


We realize that many users of WAVEWATCH III output may be more familiar with NetCDF (network Common Data Form). This is not a format available from NCEP operational systems.

To convert GRiB to netCDF, you will need a utility such at gribtonc, described here. Source code for gribtonc is available here as part of the UNIDATA decoders package.

The netCDF files are approximately 6 times the size of the GRiB files.


The NOMADS (NOAA Operational Model Archive Distribution System) data server offers WAVEWATCH III data access. The server can be accessed at, and offers interactive graphics, direct data downloads, and DODS/OpenDAP access.

More information on NOMADS is available here, and DODS/OpenDAP client software can be found here.

EMC/MMAB Information Topics:
WAVEWATCH III® Products, All Products, About Us, Contact Us
NOAA/ National Weather Service
National Centers for Environmental Prediction
Environmental Modeling Center
Marine Modeling and Analysis Branch
5830 University Research Court
College Park, MD 20740
About Us
Career Opportunities
Privacy Policy
Page last modified: Thursday, 13-Dec-2018 16:06:26 UTC