Global Marine Networks (GMN) is now offering 7 day wind forecasts of the world as a public service via it's GRIB Mail Robot.  The forecasts are generated daily for every region of the world. GRIB forecasts are based on the National Weather Service Wave Watch III model yielding highly accurate forecasts every 6 hours for up to 7 days into the future. All GRIB forecasts are delivered via e-mail and optimized specifically for low bandwidth wireless connections. Send e-mail to gmngrib@globalmarinenet.net for information on how to receive Free GRIB forecasts.

The GRIB files provided here are derived from the NOAA MMAB Operational Wave Model (wwave3) which is considered to be the best model available for computer generated ocean surface weather forecasts. Click here if you would like to know more about the wwave3 model.

What is a GRIB?

Gridded Binary data files (GRIB) are output files generated by computer forecasting models. They are tremendously more compact than regular weather charts and because of their size are very well suited for download via wireless means. The largest producer of GRIB weather is NOAA although other organizations such as the military and research institutions also generate GRIB files.  NOAA GRIB files are the best ones suited for marine forecasts.

Be aware that these forecasts are published without human intervention. Human forecasters do not review the data before it's published and therefore some knowledge and awareness is required by the end user. Also note that NOAA uses several models to generate GRIB files and it is the users responsibility to know the strengths and weaknesses of each forecast model before using them to plan their travels.

It is best to familiarize oneself with the GRIB files from each model for the area you travel in and compare these forecasts with other reliable weather sources before depending on them to make predictions. You will find that GRIB forecasts can be extremely accurate and in remote parts of the world possibly the only source of weather forecasting. We have had reports from users in the Beagle channel in South America that claim that the GRIB forecasts received from GMN are "spookily accurate". None the less a keep in mind that a forecast is a "forecast" and forecasts have been known to inaccurately predict the future.

GMN produces 7 day GRIB forecasts for the entire world.  The GRIB files are generated at 0015, 0615, 1215, 1815 GMT everyday.

Click here to view instructions on receiving GRIB weather files via e-mail.

GFS/AVN vs. Wwave3 GRIB Files

NOAA produces two GRIB formats suitable for Ocean wind forecasts. These GRIB formats are produced by the Global Forecast System known as GFS/AVN and the wave watch model know as wwatch3.  Both models generate similar forecasts but there are a few differences enumerated below:

Wwave3

• Generates wind forecasts at Sea Level taking into account wave and current effects.
• Forecasts are only for Ocean waters. The model does not generate forecasts for interior bodies of water such as the Mediterranean, Baltic, Black Sea, and Great Lakes.
• Does not forecasts winds over land.  This results in smaller GRIB files which is a tremendous advantage to wireless users.
• Generates forecasts for significant wave height, mean wave direction, mean wave period, peak wave period, peak wave direction, wind sea direction, and wind sea period.
• Forecasts are produced in 3 hour intervals for 7 days (168 Hours).
• Model is run 4 times a day.
• Data generated on 1x1.25 degree grids.

GFS/AVN

• Produces wind forecasts for the globe (Ocean and Land) at 10m. Wave action is not taken into effect.
• Forecasts are produced in 12 hour intervals to 7 days and then in 24 hour intervals to 14 days.
• Generates forecasts for pressure at mean sea level, 500 mb pressure height, surface temperature at 10m, relative humidity, precipitation, plus much more.
• Model is run 4 times a day.
• Data generated on 1x1 or 2.5x2.5 grids.

GMN GRIBs

GMN uses wwave3 GRIB data to generate Ocean wind and wave forecasts and GFS/AVN for pressure, temperature, 500mb. As a public service GMN delivers wwave3 wind forecasts at no charge via ftp, http, and email.  No subscription is necessary to access the wind GRIB files.  Users wishing additional data should consider using our premier data download product WeatherNet.

Advantages of GMN GRIB over other providers

• GMN GRIB files are considerably smaller. Almost by a factor of 2.
• More forecasts are packed into the files. You get forecasts for every 6 hours vs. 12 hour forecasts for most others.
• E-Mail robot syntax is simpler supporting custom regions and automatic scheduling.
• Wwave3 GRIB files used for wind forecasts.

The only disadvantage wwave3 has over GFS/AVN for wind forecasts is that it does not create wind data for interior bodies of water such as the Med, Baltic, Black Sea, etc... For these you will have to use the GFS/AVN GRIB files.

Note: The GMN mail robot will send you wwave3 GRIBs if you request a custom region or one of the static regions which does not contain an "interior" body of water. If your request a static region which contains an "interior" body of water such as the Med or Great Lakes you will receive an AVN GRIB file.

Viewing GRIB Weather

GRIB files downloaded with WeatherNet or via e-mail can be viewed on a number of different commercially available viewers. 

OCENS offers a full featured viewer call GRIB Explorer. Learn more about GRIB Explorer on our  GRIB Explorer page.

An alternative to GRIB Explorer is a simple, cost effective, and comprehensive GRIB viewer is WindPlot by Xaxero software LTD.  A full description of WindPlot and it's features can be viewed on our WindPlot web page.

Need to know more about weather forecasting with GRIB files?  Check out Chris Parker's "Coastal and Offshore Weather, the Essential Handbook".

Testimonials

Jonathan Selby - S/V Anahera

I have been using this quite a lot in the Cape Horn area and when you use the data sets provided by Global Marine Networks, the data has been found so accurate it is spooky.
 

Dave Holmes - Schooner Adventure

[I] downloaded the grib viewer and the West Atlantic file yesterday. I am VERY impressed! We are laying over at Cape Fear due to a gale, the progress of which is predicted over the next week.

GRIB Direct Download

The following is a list of supported regions. Click on the Key to download a compressed 7 day wind forecast for the selected region.

Note: Internet Explorer users will need to right click the appropriate link and select "Save Target As..." to download the file.

To view GRIB files you will need the following

• A program to uncompress the compressed GRIB files.
• A GRIB viewing program.

Visit our download page if you do not have these.

Send mail to webmaster@globalmarinenet.net with questions or comments about this web site.
Copyright © 2002 Global Marine Networks
Last modified: 07/01/08