Through a collaborative effort with NOAA/NCEP and NWS Honolulu, the University of Hawaii has implemented a global-scale WaveWatch III (WW3) model (ww3_global), which in turn provides boundary conditions for this Hawaii regional WW3: a 7-day model with a 5-day hourly forecast at approximately 5-km or 0.05-deg resolution. The primary purpose of this regional model is to capture island effects such as island shadowing, refraction, and accurate modeling of local wind waves. Hawaii WW3 is forced with winds from the University of Hawaii Meteorology Department's operational mesoscale model, which has a more suitable spatial resolution than the global scale wind field. The Hawaii regional WW3 also provides boundary conditions for nearshore island-scale models via Simulating WAves Nearshore (SWAN). 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.

Through a collaborative effort with NOAA/NCEP and NWS Honolulu, the University of Hawaii has implemented a global-scale WaveWatch III (WW3) model (ww3_global), which in turn provides boundary conditions for this Northwestern Hawaiian Islands (NWHI) regional WW3: a 7-day model with a 5-day hourly forecast at approximately 5-km or 0.05-deg resolution. The primary purpose of this regional model is to capture island effects such as island shadowing, refraction, and accurate modeling of local wind waves. NWHI WW3 is forced with winds from the University of Hawaii Meteorology Department's operational mesoscale model, which has a more suitable spatial resolution than the global scale wind field. 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.

Through a collaborative effort with NOAA/NCEP and NWS Honolulu, the University of Hawaii has implemented a global-scale WaveWatch III (WW3) model (ww3_global), which in turn provides boundary conditions for this Mariana Islands regional WW3: a 7-day model with a 5-day hourly forecast at approximately 5-km or 0.05-deg resolution. The primary purpose of this regional model is to capture island effects such as island shadowing, refraction, and accurate modeling of local wind waves. The Mariana regional WW3 also provides boundary conditions for nearshore island-scale models via Simulating WAves Nearshore (SWAN). 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.

Through a collaborative effort with NOAA/NCEP and NWS Honolulu, the University of Hawaii has implemented a global-scale WaveWatch III (WW3) 7-day model with a 5-day hourly forecast at approximately 50-km or 0.5-deg resolution. The global model is forced with NOAA/NCEP's Global Forecast System (GFS) winds. This model is designed to capture the large-scale ocean waves and provide spectral boundary conditions for the Hawaii and other Pacific regional WW3 models. 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.

Regional Ocean Modeling System (ROMS) 7-day, 3-hourly forecast for the region surrounding the islands of Samoa at approximately 3-km resolution. Boundary conditions provided by the global, 1/12-degree (~9-km) HYbrid Coordinate Ocean Model (HYCOM). Atmospheric forcing generated by the Weather Research and Forecasting (WRF) model for the region surrounding the islands of Samoa (wrf_samoa) 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.

Barotropic tide model for the Pacific Ocean. The model is based on harmonics distributed by Oregon State University (OSU) and assimilates satellite altimetry data from TOPEX/Poseidon. It was generated using OSU Tidal Prediction Software (OTPS), modified locally by J. Potemra, using barotropic inverse tidal solutions from OSU. 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 this output with the caution appropriate for any ocean related activity.

Non-hydrostatic Evolution of Ocean WAVEs (NEOWAVE) regional tsunami model for Pago Pago Harbor on the island of Tutuila in American Samoa, categorized by earthquake magnitude and subduction zone. Includes nearshore hazard maps of surge, drawdown, and current for hypothetical advisory and warning-level tsunamis from potential sources at the Kuril-Kamchatka, New Hebrides, Tonga, and Peru-Chile subduction zones. Data are gridded at approximately 9-m resolution referenced to the WGS84 coordinate system and use a vertical datum of mean sea level (MSL). This shock-capturing, dispersive wave model computes tsunami generation, propagation, and inundation for complex flow patterns in shelf and reef environments. It has been validated with analytical, laboratory, and field benchmarks and is approved by the National Tsunami Hazard Mitigation Program. These hazard maps cover tsunamis only; other potential hazards such as wind waves and swells would be additive to the surge, drawdown, and current described by these data.

The University of Hawaii Sea Grant College Program's Hawaii and Pacific Islands King Tides Project documents high water level events known as King Tides to better understand future impacts from sea level rise and other coastal hazards. King Tides provide a window into the future because today's high tides are predicted to become tomorrow's average sea levels. Citizen scientists have contributed to this free, publicly-accessible, and crowd-sourced dataset by photographing King Tides at places important to them throughout Hawaii and Oceania. Photos, observations, date, time, location, and other metadata are submitted online. This publicly-accessible online database informs research, policy, and decision making across the State of Hawaii and the wider Pacific region. King tides are the highest astronomical tides of the year. The scientific term for a King Tide is a perigean spring tide. King Tides in the Hawaiian Islands tend to occur during the summer (e.g., July and August) and winter months (e.g., December and January) in conjunction with new moons and full moons. King Tides, or the highest high tides of the year, are a unique coastal hazard. The timing of these extreme water level events can be anticipated through the use of tidal predictions, yet their impacts (e.g., coastal flooding and inundation in low-lying areas) can have devastating consequences for coastal inhabitants, particularly when combined with severe weather or high wave events. It is a common misconception that King Tides are the result of man-made climate change. When in reality, they are not byproducts of climate change, rather they are windows for us to see what the future of sea level rise from global climate change might look like along our coastlines. With future sea level rise we can expect more frequent high tide flooding and monthly and even daily high tides exceeding coastal inundation thresholds. When sharing these photographs, please cite this project with the following attribution: (c) Hawaii Sea Grant King Tides Project, (year of photo). Some rights reserved. Licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0).

Regional Ocean Modeling System (ROMS) 7-day, 3-hourly forecast for the region surrounding the main Hawaiian Islands at approximately 4-km resolution. Boundary conditions provided by the global, 1/12-degree (~9-km) HYbrid Coordinate Ocean Model (HYCOM). Atmospheric forcing generated by the Weather Research and Forecasting (WRF) model for the region surrounding the main Hawaiian Islands (wrf_hi) at approximately 6-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; surface currents from PacIOOS high-frequency radios (HFR); and in-situ water temperature and salinity profiles from ARGO floats and ocean glider autonomous underwater vehicles (AUV). 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.

Tide model for the Big Island of Hawaii. The model is based on climatological stratification, but 64 harmonics are used to model the full-depth baroclinic tides. The model has been run at 1km resolution, hourly, through the end of 2025. Due to computing limitations, the model grid is divided into two pieces, one for the Northwestern main Hawaiian Islands (Kauai, Oahu, Maui) and the other for the Big Island. 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 this output with the caution appropriate for any ocean related activity.