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GMDSS

NATIONAL WEATHER SERVICE PARTICIPATION IN THE GMDSS

In February 1999, the Global Maritime Distress and Safety System (GMDSS) became the primary international means for disseminating Maritime Safety Information (MSI) to mariners. The goals of the Global Maritime Distress and Safety System (GMDSS) are to provide more effective and efficient emergency and safety communications and disseminate Maritime Safety Information (MSI) to all ships on the world's oceans regardless of location or atmospheric conditions. MSI includes navigational warnings, meteorological warnings and forecasts, and other urgent safety related information. GMDSS goals are defined in the International Convention for the The Safety Of Life At Sea (SOLAS) and affects vessels over 300 gross tons and passenger vessels of any size.

The National Weather Service participates directly in the GMDSS by preparing meteorological forecasts and warnings for broadcast via NAVTEX, HF Narrow Band Direct Printing (NBDP) and SafetyNET.

The World Meteorological Organization (WMO) has developed a GMDSS Webpage which, as a first step, provides links to worldwide meteorological bulletins and warnings issued for the high seas via SafetyNet. Click here for a transmission schedule for full GMDSS Service.

The NWS also offers other international communication services which provide weather, water and climate information to segments of the World Meteorological Organization (WMO) International community.

The U.S. Coast Guard Navigation and Vessel Inspection Circular (NVIC) 3-99 on GMDSS and EPIRB Equipment Requirements on Commercial Vessels is available in Acrobat (PDF) format. It replaces NVIC 9-93.

Operation of a shipboard radio installation requires a license and is regulated by the FCC. The exception to this is the Telecommunications Act of 1996 permits recreational boaters to have and use a VHF marine radio. For further information, see the FCC's Wireless Telecommunication Bureau's Maritime Mobile Service Webpage. Licensing is not normally required when receiving only. Learn more about GMDSS and other marine communication systems by visiting the U.S. Coast Guard Maritime Telecommunications Information webpage.

Under GMDSS regulations, reception of MSI is mandatory.

"While at sea, vessels must maintain radio watches for broadcasts of maritime safety information on the appropriate frequency or frequencies on which such information is broadcast for the area in which the ship is navigating." 47 CFR 80.1123(b).

Waivers for inoperative GMDSS equipment which can not be repaired prior to scheduled sailing should be requested of the FCC by phone or email to Ghassan Khalek (202-418-2771, gkhalek@fcc.gov, 202-418-2643(fax)) identifying other systems available, planned repair date, duration of next voyage, destination etc.

Also under U.S. GMDSS regulations,

"Ships must carry the most recent version edition of the IMO publication entitled GMDSS Master Plan of Shore Based Facilities". 47 CFR 80.1085(ii)(d). This document is available from the IMO. The FCC allows NGA Publication 117 to be carried as an alternative to the GMDSS Master Plan.

Refer to NGA Publication 117, which is updated through the Notice to Mariners, for the latest official listing of NAVTEX and SafetyNET broadcast schedules. The British Admiralty List of Radio Signals is an excellent reference source for GMDSS information.

All NWS marine forecasts rely heavily on the Voluntary Observing Ship (VOS) program for obtaining meteorological observations.

NAVTEX

National Weather Service Marine Products via NAVTEX

NAVTEX is an international automated medium frequency (518 kHz) direct-printing service for delivery of navigational and meteorological warnings and forecasts, as well as urgent marine safety information to ships. It was developed to provide a low-cost, simple, and automated means of receiving this information aboard ships at sea within approximately 200 nautical miles of shore. NAVTEX stations in the U.S. are operated by the U.S. Coast Guard. There are no user fees associated with receiving NAVTEX broadcasts. Within the U.S., there are no current plans to broadcast NAVTEX on the alternate designated frequencies of 490 or 4209.5 kHz.

Here is some more information about NAVTEX broadcasts from the US Coast Guard: https://www.navcen.uscg.gov/?pageName=NAVTEX

If you experience difficulties receiving weather forecasts via NAVTEX, it could be a transmission issue, equipment issue, or combination of both. Be certain your NAVTEX receiver has been properly programmed with proper NAVTEX station and subject identifiers. A minimum of 4 forecasts should be received daily. Both good and poor reception reports, stating your position, date/time(s), and make/model of your NAVTEX receiver to; marine.weather@noaa.gov would be greatly appreciated.

The NAVTEX forecast area for the New Orleans transmitter will cover the northern Gulf of Mexico from the Suwanee River, FL to the mouth of the Rio Grande, out 200 nm. The Miami NAVTEX forecast area will cover the waters around the peninsula of Florida from Suwanee River on the Gulf Coast, to Flagler Beach on the Atlantic Coast, out 200 nm. The San Juan forecast area will cover the waters within 200 nm of the San Juan transmitter, to include the Mona Passage and part of the Anegada Passage.

NAVTEX is a major element of the Global Marine and Distress Safety System (GMDSS). For further information on NAVTEX, the GMDSS, and worldwide NAVTEX schedules, including coverage diagrams, visit the U.S. Coast Guard Maritime Telecommunications Information webpage.

NAVTEX receivers which are approved for GMDSS, contain an internal printer and cost between $800-$1500. A new generation of NAVTEX receivers intended for non-GMDSS applications such as the recreational community is also available. These receivers include such features as LCD screens and RS-232 output and have a purchase price in the $300-$500 range.

The National Weather Service issues a series of forecast products specifically tailored to fit the broadcast ranges of the U.S. Coast Guard NAVTEX transmitters on the CONUS and Puerto Rico. The NAVTEX forecast products are a blend of the existing offshore marine forecasts and coastal marine forecasts, however, the inshore portion of these forecasts contain less detail than available in the coastal forecasts. Mariners can continue to obtain NWS coastal marine forecasts by other means including NOAA Weather Radio, USCG MF Voice, USCG VHF Voice, NOAA telephone recordings and the Internet.  The U.S. has no NAVTEX coverage in the Great Lakes, though coverage of much of the Lakes is provided by the Canadian Coast Guard. 

SITOR (NBDP) is similar in many respects to NAVTEX but does not offer all of the same functionality such as avoiding repeated messages.

A Listing of NWS Marine Products Broadcast via U.S. Coast Guard NAVTEX is available.

For a complete listing of NWS marine text products (with links) visit the NWS Production Schedule for Marine Text Products webpage.

Refer to NGA Publication 117, which is updated through the Notice to Mariners, for the latest official listing of U.S. Coast Guard and worldwide broadcast schedules. The British Admiralty List of Radio Signals is an excellent reference source for NAVTEX and GMDSS information.

All NWS marine forecasts rely heavily on the Voluntary Observing Ship (VOS) program for obtaining meteorological observations.

Station Identifier WX Broadcast Schedule (UTC)
Adak X (Broadcast no longer available)
Kodiak1 J
X
0130, 0530, 09302, 1330, 1730, 21302
0350, 0750, 11502, 1550, 1950, 23502
Astoria W 03402, 0740, 1140, 15402, 1940, 2340
San Francisco C 0020, 04202, 0820, 1220, 16202, 2020
Cambria Q 02402, 0640, 1040, 14402, 1840, 2240
Marianas V 0330, 0730, 1130, 1530, 1930, 2330
Honolulu O 0220, 0620, 10202, 1420, 1820, 22202
Boston F 0050, 0450, 08502, 1250, 1650, 20502
Portsmouth N 02102, 0610, 1010, 14102, 1810, 2210
Charleston E 0040, 0440, 08402, 1240, 1640, 20402
Miami A 0000, 0400, 08002, 1200, 1600, 20002
San Juan R 02502, 0650, 1050, 14502, 1850, 2250
New Orleans G 0100, 0500, 09002, 1300, 1700, 21002

1. Kodiak also broadcasts weather forecasts during time slots initially allocated to Adak.

2. Routine weather forecasts are broadcast four times per day with these being the normal times when repeats of Notices to Mariners are broadcast in lieu of weather. Weather warnings may be broadcast at any time.

The U.S. Coast Guard may on occasion have to defer or shorten the broadcast of a scheduled weather forecast via NAVTEX to ensure delivery of more urgent navigational and safety warnings.

NAVTEX receivers must be programmed with proper NAVTEX station and subject identifiers in order to receive weather broadcasts.

U.S. NAVTEX broadcasts of weather forecasts containing a warning or a Dense Fog Advisory will be broadcast with a Subject Indicator of "B" vs. "E", such that receipt cannot be suppressed on the user's equipment. Mariners are encouraged to include subject indicator "E" in programming their NAVTEX in order to receive routine weather forecasts as well as weather warnings via NAVTEX.

INMARSAT-C SafetyNET

National Weather Service Products via Inmarsat-C SafetyNET

Inmarsat-C SafetyNet is an internationally adopted, automated satellite system for promulgating weather forecasts and warnings, marine navigational warnings and other safety related information to all types of vessels and is part of the Global Maritime Distress and Safety System (GMDSS). There are no user fees associated with receiving SafetyNET broadcasts.

InMarsat migrated its older satellites to newer ones in 2018. The SafetyNet Migration Guide is here.

See NGA Publication 117 and the U.S. Coast Guard Maritime Telecommunications Information webpage for a complete description of SafetyNET and the GMDSS as well as worldwide schedule information. The British Admiralty List of Radio Signals is an excellent reference source for SafetyNET and other GMDSS information.

A copy of the latest "The SafetyNET Users Handbook" (Electronic) is available from Inmarsat.

The National Weather Service prepares high seas forecasts and warnings for broadcast via SafetyNET for two ocean areas four times daily. These areas are known as METAREA IV and METAREA XII and cover much of the western North Atlantic and the eastern North Pacific Oceans. Click here for a map of METAREAS around the world.

These broadcasts are prepared cooperatively by the Ocean Prediction Center, National Hurricane Center and Honolulu Forecast Office. See table below for broadcast schedule.

All NWS marine forecasts rely heavily on the Voluntary Observing Ship (VOS) program for obtaining meteorological observations.

 
SATELLITE METAREA PRODUCT ID BROADCAST TIMES (UTC)
AOR-E IV (NW Atlantic)1 HSFAT1 0430, 1030, 1630, 2230
AOR-E2 IV (Hudson Bay)2 Hudson Bay via Environment Canada 0300, 1500
AMER, APAC XII (NE Pacific) HSFEPI 0545, 1145, 1745, 2345
AOR-E IV (NW Atlantic) TCMAT1..5 As required, up to 4 times daily per active tropical storm
AMER, APAC XII (NE Pacific) TCMEP1..5 As required, up to 4 times daily per active tropical storm
AMER, APAC XII (NE Pacific) TCMCP1..5 As required, up to 4 times daily per active tropical storm
AMER, APAC XII (NE Pacific) TSUPAC(Pacific) As required for tsunami
AMER, APAC XII (NE Pacific) TSUHW1(Hawaii) As required for tsunami
AMER, APAC XII (NE Pacific) TSUHWX(Hawaii) As required for tsunami
AMER, APAC XII (NE Pacific) TSUWCA(AK,BC,WA,OR,CA) As required for tsunami
AMER, APAC XII (NE Pacific) TSUAK1(AK,BC,WA,OR,CA) As required for tsunami
AOR-E IV (NW Atlantic) TSUAT1(Canada, Eastern and Gulf States, Puerto Rico, U.S Virgin Islands) As required for tsunami
AOR-E IV (NW Atlantic) TSUATE(Canada, Eastern and Gulf States, Puerto Rico, U.S Virgin Islands) As required for tsunami
AOR-E IV (NW Atlantic) TSUCAX (Caribbean) As required for tsunami
AMER, APAC XVII OFFAFG (Offshore U.S. Arctic) Provided to Canada for use as part of Canada's Metarea XVII broadcast at 0300 and 1500
AMER, APAC XVII CWFNSB (Coastal U.S. Arctic) Provided to Canada for use as part of Canada's Metarea XVII broadcast at 0300 and 1500
1 Excludes Hudson Bay. The U.S. high seas forecast for METAREA IV is currently limited to the western part of the North Atlantic Ocean eastwards of the North American coast to 35°W, from 7°N to 67°N, including the Gulf of Mexico and Caribbean Sea.
2 See this advisory from Environment Canada about their providing marine forecast and ice information services to northwestern sections of METAREA IV including Hudson Bay and approaches which use “rectangular area referencing” so as to ensure that Inmarsat-C receivers aboard vessels navigating outside this area do not display marine forecast messages extraneous to the vessels’ area of operation. Users should note that these meteorological forecasts received by their Inmarsat-C terminals may be labeled as navigational.

Inmarsat-C GMDSS equipment must be programmed to the proper Metarea/Navarea in order to receive SafetyNET broadcasts.

Inmarsat-C GMDSS equipment must also be interconnected with a GPS receiver or updated with a manually entered position at least every 12 hours or SafetyNET broadcasts for several Metareas/Navareas will be received unintentionally.