Today, the OPC website will be unavailable beginning at 0700 EDT/1100 UTC for approximately 30 min. Please refresh your browser or navigate to https://ocean.weather.gov after the maintenance window to see the upgraded version of OPC's website.
This is a non-operational test website. For official OPC information and forecasts, please refer to the operational OPC website: https://ocean.weather.gov.

OPC Gridded Marine Forecasts

The Ocean Prediction Center's gridded marine forecasts are now available in the National Digital Forecast Database (NDFD).

Gridded forecasts of marine weather elements are available over OPC's North Atlantic and North Pacific areas of responsibility (AOR).

The gridded marine parameters include:

  • surface (10-m) wind speeds with direction (KT)
  • surface (10-m) wind gusts (KT)
  • significant wave heights (FT)
  • marine hazards

These elements are available at a spatial resolution of 5 km and a temporal resolution of three (3) hours out to 144 hours or six (6) days.

The grids are produced by forecasters using the AWIPS Graphical Forecast Editor (GFE). The Atlantic basin and the Pacific basin grids will be available for forecast days 1-6 at approximately 4:20 UTC, 10:20 UTC, 16:20 UTC and 22:20 UTC each day. This schedule will be in effect beginning Tuesday, September 16, 2014 at 16:20 UTC. More information is available at http://www.nws.noaa.gov/os/notification/pns14offshore_highseas_aab.htm.

NDFD posts new day 1-3 grid files 24 times per day. NDFD includes new day 4-7 grid files only for the issuances at 00 UTC, 06 UTC, 12 UTC, 18 UTC, and 22 UTC. For the oceanic domain, grid files are posted at about 20 minutes past the hour. NDFD adds a new forecast day (24 hours) once per day with the issuance at 22 UTC. Expired forecast grids are dropped throughout the day.

With this implementation, forecasts for these elements are available from NDFD in the following standard methods:

  • Gridded Binary Version 2 (GRIB2) files via Hypertext Transfer Protocol (HTTP) and File Transfer Protocol (FTP)
  • Extensible Markup Language (XML) via Simple Object Access Protocol (SOAP)
  • Graphics via web browser

More details regarding this experimental service are available in the Product Description Document from the online catalog of experimental NWS products and services. Please note the National Hurricane Center was first to distribute gridded marine products so there will be references to NHC in the documentation.

View Graphical Forecasts

[NDFD example grids - click to access viewer]

The marine forecast images are available via the NDFD graphical interface. Select the "Oceanic" option to view wind speed, wind gusts, significant wave heights, and hazards for the National Hurricane Center, Ocean Prediction Center, CONUS, Alaska, Hawaii, and Guam areas of responsibility.

Access Gridded Data

The NDFD oceanic domain covers the Atlantic, Pacific, and Arctic basins for the offices issuing offshore waters and high seas forecasts. The upper right lat, lon for this grid is: 79.99N, 10.71E. The lower left corner lies directly on an NCEP grid 204 point, which coincides with all other Pacific region NDFD grids. The lower left lat, lon for this grid is 30.42S, 129.91E.

Specific information on the NDFD grid domains, including the oceanic domain, can be found at http://graphical.weather.gov/docs/ndfdSRS.htm.

Technical information on accessing and using NDFD elements, including their temporal resolution, can be found at http://ndfd.weather.gov/technical.htm.

The GRIB2 marine data on the NDFD oceanic domain can be downloaded at the following locations (please note the source GRIB2 files use International System [SI] units):

Forecast Days GRIB2 Download Locations (HTTP & FTP)
1-3 http://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndfd/AR.oceanic/VP.001-003/
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndfd/AR.oceanic/VP.001-003/
4-6 http://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndfd/AR.oceanic/VP.004-007/
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndfd/AR.oceanic/VP.004-007/

Note: Areas of the NDFD oceanic domain that coincide with the NDFD CONUS domain are included in the CONUS grids as well. Use the NDFD anonymous FTP menu page to access the CONUS and other regional GRIB2 files.

Tools and Utilities

NCEP provides some software utilities for users who need to convert and manipulate GRIB2 datasets. Although they are not supported, they can be downloaded from http://www.nco.ncep.noaa.gov/pmb/codes/GRIB2/

Comments & Feedback

The marine elements will remain experimental until the NWS assesses feedback and completes a technical analysis. At that time, the NWS will determine whether to move these experimental elements to operational status, discontinue them, or revise and extend the experimental feedback period.

Comments and feedback on the experimental gridded marine elements are welcome at:
http://www.nws.noaa.gov/survey/nws-survey.php?code=EGOSWHSMF

General feedback on NDFD GRIB2 service:
http://www.weather.gov/survey/nws-survey.php?code=ndfd-grids

General feedback on NDFD XML SOAP service:
http://www.weather.gov/survey/nws-survey.php?code=xmlsoap