The operational ocean wave predictions of NOAA/NWS/NCEP use the wave model WAVEWATCH III using operational NCEP products as input. The model is run four times a day: 00Z, 06Z, 12Z, and 18Z. Each run starts with 9-, 6- and 3-hour hindcasts and produces forecasts of every 3 hours from the initial time out to 180 hours (84 hours for the Great Lakes).

The wave model is run as a mosaic of eight grids (one global, four regional, and three costal) with two - way interaction between the grids.

Details of the wave model can be found here http://polar.ncep.noaa.gov/waves/wavewatch/wavewatch.shtml