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WEATHER ARTICLEWeather on Demand:Getting Your Weather FAX WeatherWhen You Want ItBy Gary JensenOne of the lessons learned from this summer’s hurricaneexperience is the need to be able to download, or otherwiseaccess, weather information when you need it. Duringhurricane season, tropical depressions (TD) form unexpectedly;known TDs can spin up into hurricanes, and both tendto erratically change their direction of movement. Stayingout of the way of these storms and severe weather phenomenarequires skippers to have the most current and up-todateweather information available.Offshore sailors traditionally get their weather mapsand forecasts by receiving regularly scheduled Weather FAX(WEFAX) transmissions 1 . WEFAX systems used to copythese weather data usually consist of a marine SSB or Hamtransceiver, a WEFAX decoding device (usually the soundcard or inexpensive demodulator), and a laptop computerrunning some type of WEFAX software. A skipper withinlistening range of a broadcasting WEFAX station using thistype of system can copy weather maps, satellite images, andforecasts when they’re broadcast. While relatively inexpensive,this system exhibits several limitations, the most significantbeing:The fixed broadcast schedule governs when WEFAXinformation is available, not the skipper’s need.The readability (print quality) of received WEFAX documentswill vary from excellent to unreadable, dependingon signal strength, noise, and other propagation conditions.Boaters Aren’t Always Available to Receive aScheduled FaxRunning a boat places many demands upon a skipper andcrew. Stuff happens on board boats, and when it happens,skipper and crew must deal with it in real time. When theskipper and crew are busy tending to the boat’s needs, theyare not free to copy a scheduled WEFAX broadcast. Theydon’t have time to stop what they are doing, go below, turnon a SSB, tune in a WEFAX station, set the computer toreceive/decode a received WEFAX transmission, and monitorthe process. Skippers need the ability to retrieve the most30 December 2004 SOUTHWINDS www.southwindssailing.com
ecent WEFAX data when they want it, not just when abroadcaster sends it.Airmail 2 , the network client software that works withthe Sailmail 3 and Winlink2000 (WL2K) 4 networks, includestechnology that makes it possible to indirectly requestWEFAX documents from the Internet. The ability to proactivelyrequest WEFAX documents over the Sailmail andWinlink e-mail networks solves the above mentioned problems:it permits skippers to request the most recent WEFAXdocuments when they need them; and because the Sailmailand Winlink networks are digital, it guarantees that thereceived WEFAX documents will be clean, distortion-freereplicas of the originals.Receiving Weather When You Want ItThere are three ways to request and receive weather documentsthru the Sailmail or Winlink networks. These are:1. Catalog Sheets (Available to WL2K Users)Using Airmail with the WL2K network, skippers can easilyaccess several hundred weather-related documents throughthe built-in catalog sheets. Weather documents are requestedby placing a check mark in the square associated with thedesired weather document. When Airmail next connects tothe WL2K network, it will request the checked documentsfrom the WL2K server. Requested documents stored on theserver will be sent during the connect session. The serverwill “fetch” from the Internet documents not stored on theserver and send them to the requesting station during thenext session. Figure 1 shows a partial listing ofweather–related and other documents available throughAirmail’s catalog sheetsFigure-1Airmail Catalog Sheet2. National Weather Service (NWS) FAX-BackSkippers with Pactor-III capable radio modems can use theNWS FAX-back service to retrieve weather documents. TheFAX-back system works by sending a command script to theNWS at ftpmail@weather.noaa.gov. The NWS FTP serverexecutes the script, fetches the requested documents, andsends them to your e-mail address. Table 1shows an example ofa script instructingthe NWS WEFAXFTP server to fetchfive different documentsand send themto yourcall@winlink.org.The To: linecontains the addressof the NWS FTP FAX-Back server, and theTable 1NWS FAX-back ScriptTo: ftpmail@weather.noaa.govFrom: yourcall@winlink.orgSubject: Anything or leave blankopencd faxget rfaxmex.txtget rfaxatl.txtget rfaxpac.txtget PPAE11.TIFget PYEB86.TIFFrom: line containsthe return address where the requested documents will besent. The Subject: line can contain anything you like, or canbe left blank, and the body of the message contains the executablescript.If the above scripting looks a bit stilted and non-userfriendly to you, you’re right, it is. The script in Table-1 isactually a short computer program that follows a definedprotocol with specific command and format guidelines.The key to making the NWS Fax-back system work is tohave an accurate listing of the file names for the NWS products.The NWS produces an extensive list of weather products,with more than 130 documents covering the Atlantic,Gulf and Caribbean regions. To request a copy of the latestproduct listings, follow the format shown in Table-1 andsend an e-mail to ftpmail@weather.noaa.gov.After the cd fax line, type the weather products listingyou need; get rfaxatl.txt for the Atlantic area, and getrfaxmex.txt for WEFAX products covering the Gulf. TheseWEFAX listings are also available on the Internet fromhttp://weather.noaa.gov/pub/fax.3. SaildocsSaildocs is an Internet-based service similar in nature to theNWS FAX-back service, but much easier to use. You canretrieve the same NWS WEFAX forecasts, maps, and satellitepictures that you get through the NWS FAX-back serv-Local News For Southern Sailors SOUTHWINDS December 2004 31
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Page 11 and 12: FROM THE HELMCharges Dropped Agains
Page 15 and 16: LETTERS Continued from page 10edito
Page 17 and 18: Overall, reports from major exhibit
Page 19 and 20: FREESAVE $ 2049 99Saltwater Tool Ki
Page 22 and 23: Surviving the HurricanesBut Then Al
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Page 26 and 27: The Sailboat Damaged by the Storm v
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Page 31: as the boat heels, reducing dragto
Page 36 and 37: Regional SailingServices DirectoryS
Page 38 and 39: SOUTHEAST COAST SAILINGThere were f
Page 40 and 41: EASTERN FLORIDA COASTJacksonvilleDa
Page 42 and 43: EASTERN FLORIDA COASTLake Eustis’
Page 44 and 45: Five Speed leads theSpinnaker A fle
Page 46 and 47: SOUTHEAST FLORIDA COASTvert from a
Page 48 and 49: NORTHERN GULFCOAST SAILINGFlorida P
Page 50 and 51: NORTHERN GULF COAST SAILINGWaveland
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Page 54 and 55: WEST FLORIDA COASTCedar Key to Cape
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Page 60 and 61: WEST FLORIDA SAILINGRiver Romp Rega
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Page 70 and 71: CLASSIFIED ADS I NDEX OF A DVERTISE
Page 72: Is it a bird,a plane or?A Hurricane

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