The GFS Wave Model is the primary workhorse used by the National Weather Service to forecast wave heights across the globe. GFS is shorthand for the NCEP/EMC global deterministic wave model unified into NOAA's Global Forecast System (GFS). The GFS wave model is built on the WAVEWATCH III spectral wave model, which is one way coupled to the GFS atmospheric forecast model. In addition, surface ocean currents from the Global Real-Time Ocean Forecast System (RTOFS) are input to the wave model. The wave model has a spatial resolution of 0.16 x 0.16 degrees. The model is run by NCEP four times a day: 00Z, 06Z, 12Z, and 18Z and produces hourly forecasts out to 120 hours and three-hourly forecasts from 120 to 384 hrs (5-16 days). There are three native computational grids, one for the arctic, one for one for the northern hemisphere (15S to 52.5N), and one for the southern hemisphere (10.5S to 79.5S). There are four post-processed grids.

NCEP (National Center for Environmental Prediction) is the part of the US National Weather Service responsible for running the myriads of numerical weather prediction models covering aviation weather, atmospheric forecasts, ocean wave forecasts and space weather, and disseminating the results. EMC is the Environmental Modeling Center. EMC is responsible for the development, improvement, and implementation of numerical prediction systems.

Warning - Forecasting wave heights within 1.5 foot (0.45 m) of the actual wave height, as recorded by a wave buoy, is typically excellent to very good out to 3 days, fair to middling from 3 - 7 days, poor from 7 - 10 days, and statistical noise for forecasts longer than 10 days. This holds for any and all wave models you may be looking at, no matter how fancy the presentation. We provide long-range forecasts with this in mind, Caveat Emptor. To confirm this, a comparison of GFS and WAM wave forecasts compared to NDBC wave buoy data can be reviewed at Wave Model Validation