Regional Ocean Modeling System (ROMS) 6-day, 3-hourly forecast for the region surrounding Guam and parts of the Commonwealth of the Northern Mariana Islands (CNMI) at approximately 2-km resolution. Boundary conditions provided by the wider ROMS model for the region surrounding the Western North Pacific (ROMS_MARI) at approximately 4-km resolution. Atmospheric forcing generated by the Weather Research and Forecasting (WRF) model for the region surrounding Guam and parts of the Commonwealth of the Northern Mariana Islands (CNMI) (WRF_Guam) at approximately 3-km resolution. Tide forcing uses the Oregon State University (OSU) Tidal Prediction Software (OTPS) TOPEX/Poseidon global inverse solution (TPXO) to derive barotropic tidal elevation and velocity. Data are assimilated over the previous 3 days using all available observations to improve the model estimate of current ocean state (its nowcast) before forecasts are run. Assimilated observations may include satellite-based sea surface temperatures from MODIS, AVHRR, or OSTIA; satellite-based sea surface height from AVISO; and in-situ water temperature and salinity profiles from ARGO floats. While considerable effort has been made to implement all model components in a thorough, correct, and accurate manner, numerous sources of error are possible. As such, please use these data with the caution appropriate for any ocean related activity.