National Weather Service United States Department of Commerce
Webpages of interest to the mariner. The U.S. Coast Guard Maritime Telecommunications webpage contains an excellent description of marine communication systems. See these pages for further links.

 

NOAA Homepage https://www.noaa.gov
NWS Homepage https://www.weather.gov
NWS Marine Forecasts https://www.weather.gov/marine/
NWS Marine Text Products https://www.weather.gov/marine/forecast
NWS Marine Charts (Radiofax) https://www.weather.gov/marine/radiofax_charts
NWS Environmental Modeling Center https://www.emc.ncep.noaa.gov/
NWS Ocean Prediction Center (formally the Marine Prediction Center) https://ocean.weather.gov/
National Hurricane Center and Central Pacific Hurricane Center https://www.nhc.noaa.gov
Joint Typhoon Warning Center https://www.metoc.navy.mil/jtwc/jtwc.html
NWS Marine Forecast Offices https://www.weather.gov/marine/marine_map
NWS Ocean Modeling Branch https://polar.ncep.noaa.gov
NWS National Tsunami Warning Center (NTWC) https://www.tsunami.gov/
NWS Pacific Tsunami Warning Center (PTWC) https://www.tsunami.gov/
The International Tsunami Information Center http://itic.ioc-unesco.org/
Caribbean Tsunami Warning Program https://www.weather.gov/ctwp/
National Tsunami Hazard Mitigation Program https://nws.weather.gov/nthmp/
USGS National Earthquake Information Center https://neic.usgs.gov/
NWS EMWIN https://www.weather.gov/emwin/index.htm
NWS VOS Program https://www.vos.noaa.gov
NWS Publications https://www.weather.gov/owlie/publication_brochures
NOAA Data Buoy Center https://www.ndbc.noaa.gov/
NOAA Weather Radio https://www.nws.noaa.gov/nwr/
NOAA Tides & Currents https://tidesandcurrents.noaa.gov
NOAA Ports https://tidesandcurrents.noaa.gov/ports.html
NOAA SEAS Program https://seas.amverseas.noaa.gov/seas/
NOAA NESDIS https://www.nesdis.noaa.gov/
NOAA's National Centers for Environmental Information (NCEI) https://lwf.ncdc.noaa.gov/oa/ncdc.html
NOAA's National Oceanographic Data Center (NODC) https://www.nodc.noaa.gov
NOAA Coastwatch https://coastwatch.noaa.gov/cw/index.html
NOAA GOES https://www.goes.noaa.gov
NOAA's Atlantic Oceanographic and Meteorological Laboratory (AOML) https://wwww.aoml.noaa.gov/
NOAA's Pacific Marine Environmental Laboratory (PMEL) https://pmel.noaa.gov
NOAA's Office of Response and Restoration https://response.restoration.noaa.gov
NGA Maritime Safety Information https://msi.nga.mil/NGAPortal/MSI.portal
Maritime Administration (MARAD) https://www.marad.dot.gov
International Ice Patrol https://www.navcen.uscg.gov/?pageName=IIPHome
National Ice Center https://www.natice.noaa.gov
Naval Oceanography Portal https://www.usno.navy.mil
Navy Fleet Numerical https://www.fnmoc.navy.mil
U.S. Coast Guard Homepage https://www.uscg.mil
U.S. Coast Guard Office of Search & Rescue (CG-534) https://www.uscg.mil/hq/cg5/cg534/default.asp
U.S. Coast Guard Rescue Coordination Centers (RCCs) https://www.uscg.mil/hq/cg5/cg534/RCC_numbers.asp
U.S. Coast Guard Navigation Center https://www.navcen.uscg.gov
U.S. Coast Guard Maritime Telecommunications Information https://www.navcen.uscg.gov/?pageName=maritimeTelecomms
U.S. Coast Guard CAMSLANT Comms https://www.uscg.mil/lantarea/camslant
U.S. Coast Guard CAMSPAC Comms https://www.uscg.mil/pacarea/camspac/
U.S. Coast Guard COMMCOM https://www.atlanticarea.uscg.mil/Atlantic-Area/Units/Area-Units/Communications-Command/
U.S. Coast Guard AMVER Program https://www.amver.com/
IMO Homepage https://www.imo.org
WMO Homepage https://www.wmo.ch
The Radio Technical Commission for Maritime Services (RTCM) http://www.rtcm.org/

 

There are also many other Internet sites of interest to the mariner. Use one the Internet search engines to search on topics such as "marine weather", "radiofax", "radiofacsimile", "weather buoys", "tides", etc.