GENERAL TYPES OF NATIONAL WEATHER SERVICE PRODUCTS

Most of the observational and prognostic data routinely received from foreign countries by NWS is in the form of digital messages, although some digital charts are received. The National Weather Service computers at the National Meteorological Center (NMC) automatically receive and process all data received from North America and the remainder of the world. Selected raw observa-tional data is routinely used in various numerical prediction models to produce both graphic charts and numerical bulletins.  

NWS also receives copious amounts of digital satellite imagery and computer-derived digital data from another branch of NOAAthe National Environmental Satellite, Data, and Information Service (NESDIS).  

A large portion of the data received at NMC and the products produced by NMC are available to the Department of Defense. While most of this data is provided to DOD as digital data fields (intended to load a computer with semi-processed data or computer-derived data), a good portion is provided to DOD users as either facsimile charts or electronically transmitted bulletins. In this lesson we will discuss only a few of the thousands of charts and bulletins provided by NWS.

AVAILABILITY OF NWS PRODUCTS TO NAVAL OCEANOGRAPHY COMMAND UNITS

How do you, as an Aerographer, receive these facsimile charts and electronic bulletins? Most of the NWS products you will use will come from NMC through the Department of Defense/ Defense Communications System (DOD/DCS) Global Weather Communications Systems (GWCS) Automated Weather Network (AWN). The hub of the AWN is the Automated Digital Weather Switch (ADWS) at Carswell AFB. Carswell is connected with nearly every DOD weather facility in the continental United States. NMC data and bulletins are sent directly from ADWS to your COMEDS printer or computer terminal. Additional data is sent to Fleet Numerical Oceanography Center (FNOC) Monterey for processing and further distribution via the Naval Environmental Data System (NEDS) to Naval Oceanography Command (NOC) Centers, Facilities, or Detachments. Rota, Hawaii, and Guam all may receive NWS data and bulletins via the Naval Environmental Data Net-work (NEDN).

NWS facsimile charts are retransmitted on the Air Force Digital Graphics System (AFDIGS), a second major component of the DOD/DCS GWCS. NOC Centers may receive this data via land-line circuits or satellite and retransmit selected data via their facsimile broadcasts to the fleet.

NWS operates the direct Satellite Facsimile (SATFAX) broadcast which is currently used by most U.S. Marine Corps weather detachments and many stateside NOC Detachments. NWS also operates the National Facsimile (NAFAX) circuits which are available at many CONUS NOC Units. The NAFAX circuits are being phased out and replaced by SATFAX. Additionally, NWS main-tains localized and specialized facsimile broad-casts, such as the Inter-Alaska Facsimile

(AKFAX) circuit, the Suitland-Honolulu circuit, the Tropical Analysis (TROPAN) circuit, and a special circuit for Puerto Rico and the Virgin Islands. These are available to DOD users. All of these circuits contain regional and global charts produced by NWS.

The NOC fleet facsimile broadcasts are composed mostly of FNOC-produced charts. Supplemental charts are received directly from NMC via the NWS SATFAX broadcast, the NWS Digital Facsimile (DIFAX) broadcast, or received indirectly from NMC on the AFDIGS broadcast from the Air Force Global Weather Center (AFGWC). The Navys fleet meteorological data broadcast, part of the Fleet Multi-channel Satellite Broadcast, originates at Carswell AFB, with data received from NWS. This data is supplemented with data inserted by the NOC Centers. While most of the data transmitted from outside the United States is received at the NOC Centers on the NEDN, the majority of the data, including the overseas data, is provided by NWS. It may be interesting to remember the next time you receive some local weather data aboard ship off the coast of Malaysia, that the data actually traveled around the world, from Malaysia to Switzerland; to Suitland, Maryland; to Carswell AFB, Texas; to Hawaii; to Guam; and finally to your ship.

Although the NWS regional HF teletype broadcasts were discontinued several years ago, the current operational and planned AFDIGS HF broadcasts should provide a valuable facsimile and teletype data source for our use. AFDIGS actually has four digital graphics weather circuits: CONDIGS, for the continental United States; PACDIGS, for the Pacific; HALDIGS, for Central America; and EURDIGS, for Europe. Until recently, the only way to receive any of the AFDIGS products was to be connected to a dedicated land-line/satellite circuit. Current plans for the USAF High Frequency Regional Broad-cast (HFRB) System include multiple HF radio broadcast sites for all of the AFDIGS broadcasts. AWS and NWS facsimile charts are transmitted on the upper sideband, with AWS, NWS, and foreign data and bulletins being transmitted via radioteletype on the lower sideband of each frequency. As of late 1989, the currently operational sites are Elmendorf AFB, Alaska and Elkhorn, Nebraska. Six additional sites will be brought on line by the end of 1991: Anderson AFB, Guam, for the western and central Pacific; Clark AFB, Republic of the Philippines, for the Far East and the Indian Ocean; Croton AB, England, for Europe, the eastern North Atlantic and Barents Sea; Incirlick AB, Turkey, for Southern Europe, the Mediterranean, and the Middle East; Homestead AFB, Florida, for the Caribbean, Central America, and southern United States; and one additional site for the South Atlantic, Information on frequencies and data content is contained in AWSR 55-9. Requests for frequencies and special support should be addressed to COMNAVOCEANCOM.

Additionally, limited NWS charts are available on the satellite Weather Facsimile (WEFAX) broadcasts from the geostationary Earth-orbiting satellites (GOES) operated by the National Environmental Satellite, Data, and Information Service (NESDIS). Several different NWS charts are routinely retransmitted by the Soviets, the British, the Germans, and the Italians on their meteorological HF broadcasts.

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