SUMMARY OF TROPICAL CYCLONE PRODUCTS (36kb)

Regardless of how accurate NHC forecasts of tropical cyclone activity are, they are useless unless reliable and timely methods are available to get this information to the mariner. There are many ways that tropical cyclone information is made available to the mariner. However, knowing which products are available via which source is often the difficult part in obtaining tropical cyclone information. Further information on all NWS marine products can be found at the Internet address: http://www.weather.gov/om/marine/home.htm

• Internet
• E-mail
• HF Fax
• WWV HF Voice (Time Tick)
• U.S. Coast Guard HF SITOR (SImplex Teletype Over Radio)
• U.S. Coast Guard HF Voice
• U.S. Coast Guard MF Voice
• U.S. Coast Guard VHF Voice
• NOAA Weather Radio
• NAVTEX Element of the Global Maritime Distress & Safety System
• INMARSAT-C SafetyNET

SUMMARY OF TROPICAL CYCLONE PRODUCTS AND WHERE THEY CAN BE FOUND

Internet
Although internet access at sea can often be an expensive and technically challenging alternative to obtaining tropical cyclone information, use of this method while in port is becoming more popular as access costs decrease and personal computer use among mariners increases.

A majority of NWS forecasts and warnings are now available on-line from NWS web servers. Specifically, all tropical cyclone products are available in this format directly from TPC/NHC. Additionally, these products can also be found via other National Weather Service and government web servers. Although the Internet is not part of the National Weather Service's operational data stream and should never be relied upon as the primary method of obtaining the latest forecast and warning data, web servers maintained by the National Weather Service are usually reliable and can serve as a valuable source of information for the Mariner. TABLE 1 indicates current web sites available for Atlantic tropical cyclone information. Finally, any active marine warning, including tropical cyclone related warnings can also be found on weather.gov at the following address: http://www.weather.gov/view/nationalwarnings.php

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E-mail
TPC/NHC text files & graphic charts are available via email through a NWS FTPMAIL server. This server allows Mariner's who do not have direct access to the World Wide Web but who are equipped with an email system to receive NWS products at sea or in port. Using this service, users can request files from the NWS and have them automatically e-mailed back to the user. Turnaround is generally less than three hours, however, performance may vary widely and receipt cannot be guaranteed. However, this service can be a valuable tool to the Mariner in obtaining tropical cyclone information as well as other weather information over open water areas.

To start using this service, obtain the FTPMAIL help file by:

1. Sending an email to: ftpmail@weather.noaa.gov
2. Subject Line: Anything that you like
3. Body: help

The help file that you receive via email will discuss procedures and methods of obtaining tropical cyclone information along with a listing of available products using this method. In order to get further information on tropical cyclone specific data available via this service:

1. Send an email to: ftpmail@weather.noaa.gov
2. Subject Line: Anything that you like
3. Body of message (case and line sensitive):
open
cd fax
get marine2.txt
quit

This will generate an email response with a description of tropical cyclone products and file names along with further instructions on obtaining this particular information via the FTPMAIL server.

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HF Fax
The HF Fax, also known as the radiofax or WEFAX, for years has been the mainstay of weather information for the mariner. During the tropical cyclone season in the Atlantic, information on current tropical systems in text or graphical formats can be acquired via this method. Additionally, satellite imagery is made available throughout the year via this circuit. Transmitters located in Boston and New Orleans continuously transmit weather information for the Atlantic Basin available to anyone at sea with the proper receiving equipment.

TABLE 2 lists the frequencies assigned to the Boston and New Orleans sites in addition to broadcast times for each site's current HF Fax schedule. Users should occasionally review the fax schedules at each site for changes in available products and transmission times.

Typical dedicated radiofax receivers use assigned frequencies, while receivers or transceivers, connected to external recorders or personal computers, are operated in the upper sideband (USB) mode using the carrier frequencies. From the HF Fax assigned frequencies in TABLE 3 subtract 1.9 kHz for carrier frequency. All radiofax broadcasts of NWS products use a radiofax signal of 120 lines-per-minute (LPM) and an Index-of-Cooperation (IOC) of 576. Although radio reception in the high-frequency band varies greatly with a multitude of factors, generally, frequencies above 10 MHz work best during the day, while lower frequencies work best at night.

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WWV HF Voice (Time Tick)
The National Institute of Standards and Technology (NIST) broadcasts a time and frequency service from station WWV in Fort Collins, Colorado. The "Time Tick" is normally used as an aid to celestial navigation but hourly voice broadcasts of Atlantic High Seas Warnings are transmitted at 8 & 9 minutes past the hour on the frequency signals: 2.5, 5, 10, 15, and 20 MHz.

U.S. Coast Guard HF SITOR (SImplex Teletype Over Radio)
Broadcasts of high seas forecasts and storm warnings are transmitted from the United States Coast Guard's Boston high seas communications station in the SITOR mode. These text broadcasts are performed in mode B, FEC, with broadcast times & frequencies listed in TABLE 3. Information included in these broadcasts range from weather to navigational safety text information. Transmission range of these broadcasts, as with all HF signals, is dependent on operating frequency, time of day, and multiple environmental factors.

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U.S. Coast Guard HF Voice
High seas forecasts, offshore forecasts, and tropical cyclone marine forecasts/advisories are broadcast in voice format via two United States Coast Guard transmitters operating in the Atlantic Basin. The products are broadcast via HF in the upper sideband (USB) mode using a synthesized voice known as "Perfect
Paul". This voice is very distinctive and serves as an aid in identifying and copying these weather broadcasts. TABLE 4 lists transmitter sites, frequencies, and times to copy the HF voice broadcast in the Atlantic basin.

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U.S. Coast Guard MF Voice
Medium frequency broadcasts of NWS offshore waters forecasts and storm warnings are conducted on 2670 kHz after an initial announcement on 2182 kHz (will become 2187.5 kHz sometime in the future although exact date is unavailable at time of publication). These broadcasts originate from various Coast Guard Groups located along the Atlantic & Gulf coasts of the United States with a typical range of 50-150 NM during the day to about 150-300 NM at night. TABLE 5 lists the location and transmission times of products sent via MF voice broadcast in the Atlantic Basin.

NWS offshore waters forecast products valid for the regions where the broadcasts originate are disseminated throughout the year. The tropical weather outlook and any active tropical cyclone forecast/advisories are broadcast from some of these transmitters during the Atlantic Hurricane season of 1 June through 30 November. Additionally, Group New Orleans and Group Corpus Christi broadcast various other coastal forecasts and marine or severe weather statements when applicable throughout the year.

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U.S. Coast Guard VHF Voice
Coastal water forecasts and storm warnings of interest to mariners are broadcast by the Coast Guard on VHF channel 22A (156.8 MHz VHF FM) after an initial announcement on VHF channel 16 (157.1 MHz VHF FM). The Coast Guard VHF network provides nearly continuous coverage of all coastal areas of the United States East and Gulf coasts to a range of approximately 20 NM from shore. In regions where NOAA weather radio broadcasts provide complete coverage of the USCG VHF network, the Coast Guard may elect to only broadcast storm warnings and not any NWS marine weather information. TABLE 6 lists Coast Guard stations that transmit over VHF voice along with transmission times.

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NOAA Weather Radio - visit the NOAA weather radio web site.
Local and coastal marine forecasts & warnings are broadcast across the NOAA weather radio network on a constant basis. This network provides near continuous coverage of the coastal waters in the Atlantic and Gulf of Mexico. Additionally, NOAA weather radio transmitters are located in the Caribbean region transmitting over the coastal waters of Puerto Rico & the U.S. Virgin Islands. Reception ranges of 25 NM from the coast are typical, however coverage may be more or less depending on location of vessel and transmitter.

Most VHF radios have the ability to receive NOAA weather radio over the frequencies listed in TABLE 7. However, it is recommended that a separate NOAA Weather Radio receiver be used to copy this broadcast so that the marine VHF channels can remain clear in order to copy other important information at sea.

During severe weather situations, an automated 1050 Hz tone is transmitted to automatically turn on compatible NOAA weather radio receivers. Most, but not all, NOAA weather radios possess this feature. However, an active NOAA Weather Radio channel must be selected in order for the mariner to be alerted. Additionally, newer NOAA weather radios utilize SAME (Specific Area Message Encoding) technology. This feature allows weather radios to alert only for specific weather conditions or certain geographic areas. It is recommended that SAME technology weather radios operated by mariners making coastal transits be set to the `All County Code Option' in order to avoid the need for continual reprogramming of the radio during transit. This also reduces the likelihood of missing any important weather warning information while underway.

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NAVTEX Element of the Global Maritime Distress & Safety System
NAVTEX is a low-cost, simple, and automated means of receiving important marine information aboard ships. It is an internationally accepted medium frequency (518 kHz) direct-printing service for delivery of navigational information and meteorological warnings/forecasts to ships. NAVTEX is similar to SITOR in many aspects, however SITOR does not offer the same degree of functionality that NAVTEX does, such as avoiding repeated messages. The NAVTEX system possesses typical operating ranges of approximately 200 NM from the coast.

All NAVTEX stations in the United States are operated by the Coast Guard and provide offshore forecasts of weather conditions for the region in which the transmitter is located. TABLE 9 is a listing of NAVTEX transmitter sites and scheduled broadcast times for locations along the Atlantic & Gulf coasts along with some offshore waters in the vicinity of Puerto Rico in the Caribbean region. TABLE 8 also lists the required station identifiers needed by the NAVTEX receivers in order to obtain broadcasts.

It is recommended that all mariners in U. S. waters program their NAVTEX receivers to include subject indicator "E" in order to receive both warnings & routine weather forecasts via NAVTEX. This will decrease the possibility of missing important tropical weather information at sea.

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INMARSAT-C SafetyNET
Inmarsat-C SafetyNET is an internationally adopted, automated satellite system for promulgating weather forecasts/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).

National Weather Service high seas forecasts, warnings, and tropical cyclone information (when applicable) for SafetyNET Area IV, the Atlantic Basin west of 35W Longitude and north of 7N latitude, are broadcast four times per day at 0430, 1030, 1630, and 2230 UTC.

This information is sent over the INMARSAT system of geostationary satellites with each satellite in the system transmitting on a designated channel at 1.5 GHz. Any ship sailing within the coverage area of an Inmarsat satellite is able to receive all SafetyNET messages broadcast over the appropriate channel of that satellite, so long as Inmarsat-C GMDSS equipment is programmed to the proper Metarea/Navarea (Area IV for the Western Atlantic). Additionally, Inmarsat-C 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. Finally, the broadcast transfer technology of this system is extremely reliable ensuring a high probability of receiving messages correctly during first transmission, irrespective of the atmospheric conditions or the ship's position within the satellite coverage.

NWS Telephone Support
Many National Weather Service forecast offices offer recorded marine & local weather forecasts similar to those found on NOAA Weather Radio. Numbers to these recorded forecasts can usually be found by contacting the nearest coastal National Weather Service Forecast Office (NWSFO). Some recorded tropical cyclone forecast/advisories can be obtained by contacting TPC/NHC directly at (305)229-4483.