How Do We Get Weather Information?
Where to get weather information is a subject that could (and usually does) fill a small booklet or cruising guide in virtually every cruising area of the world. I suppose the amount of information available to you is dependent on how much equipment you are willing to purchase and use, and how much time you are willing to put into gathering and interpreting the data.
I have only cruised in a few areas of the world, so I offer this limited and probably over-simplified guide to gathering weather information based upon the equipment aboard Moonshadow and my limited experience
Professional weather forecasts are nice to have, but in the best case are about 60% correct. Last season in Fiji we got whacked by a small depression that never even showed up on the Australian or New Zealand fax charts, let alone the local (Nadi) forecasts. We had half a day of gale force winds and torrential rains. That said, there is no substitute for going up on deck and having a look around. The old joke is that if the deck is wet, it’s raining. If the deck is white, it’s snowing. If you need your sunglasses to see the deck, it’s sunny. If you can’t see the deck, it’s foggy. If the boat is standing up, it’s calm. If the boat is leaning, it’s windy. The point is that there is no substitute for you senses when assessing the weather situation.
Barometers are inexpensive and small these days. They are even built into some wristwatches. There is no reason not to have one aboard. We log the bar every hour on passage and watch the trend. If it’s rising, you are moving into, or a high is moving onto you, and you should have generally fair weather. If it is falling, especially if it is falling fast, then batten down, as you will likely get some heavy weather. Depending on where in the world you are located, you can take evasive action and move toward the navigable semicircle of a strong weather system. If you have a weather fax, you can see from the bar your likely juxtaposition in a weather system.
At least one working VHF radio is essential equipment on a yacht. Most first-world countries provide at least coastal weather forecasts on some sort of regular schedule over the VHF airwaves. In the third world, you can use your VHF to gather weather information from other (perhaps better equipped) yachts, passing ships, and, in areas where there are lots of yachties, the local cruiser’s nets. If you are not sure of the schedules, check the local cruising guides, ask the local maritime services or ask anyone who has been around for a while.
In addition to local music, news and sports, the local radio stations often will have some sort of weather information, particularly in island nations such as Fiji. Since many yachts have 12-volt house electrical systems, we tend to use car stereo equipment that can receive AM/FM bands as well as play cassettes or CD’s. Be aware that in some countries, such as New Zealand, the radio bands are slightly different than the US, so you may have to buy a small piece of equipment called a “band expander” to be able to use your gear down here. Any local car stereo company can sort you out.
World Band Radio
If you don’t have the space or money to equip yourself with a SSB and/or Ham radio, for about US $100 you can get a small portable world band radio. With it you can tune into (but receive only) any local weather forecasts and cruisers nets. In this part of the world also enjoy listening to AM/FM radio and broadcasts from the BBC, Voice of America, Radio Australia and Radio New Zealand, which have great world news and commentary and in some cases, weather forecasts for the islands. Radio Shack and some other stores sell a book with the worldwide schedule of short wave radio broadcasts.
Undoubtedly the most valuable communication tool to the average cruiser is their single sideband radio. With it we can tune into local weather broadcasts, passage tracking and weather services such as Russell Radio (New Zealand) and Pentacomstat (Australia), and cruisers nets, as well as access email weather reports (with services like SailMail) and weather facsimile (when interfaced with a personal computer). In the South Pacific, Bob McDavitt’s book on South Pacific weather has a very complete list of sources and radio frequencies for weather information. In other areas, one can consult a local cruising guide or ask other cruisers for the frequencies and schedules.
Weather Facsimile (Fax)
If you have the space and money for a dedicated weather fax receiver, it is a very valuable source of information. The main advantage of a dedicated fax is that it can be programmed to receive the products we want, and then it just spits them out without the need to turn on the computer and tune up the SSB. During the cruising season, I keep the fax on full time and receive the local analyses as well as 24, 48 and 72-hour prognoses. Frequencies and fax schedules for the various stations worldwide are available in a book that is available at most nautical bookstores.
For less than US $1000 you can purchase a piece of equipment and software that, when interfaced with a PC, will send you real time photos of the sky in your area from polar earth orbit satellites as they pass overhead. I like to compare these to weather faxes to determine the extent of convergence zones and fronts and to more accurately locate the positions of weather systems that may affect us. There are a few brands available, but I have one that is made in New Zealand by Xaxero called the “Sky Eye.”
There is a plethora of weather information available on the World Wide Web. To access it, one must have a PC and some way to get on line, either via some sort of on-board satellite communication system or on land at an Internet café or via a hard telephone line. I use both. The Iridium portable satellite phone is now available for well under US$1000. For weather information I like to use the grib files available with the MaxSea nav program and forecasts and maps available on the New Zealand MetService web site.
How Critical is Weather Information?
In most cases, planning a passage around good weather information will make the difference between a comfortable passage and an ordeal, a swift passage and a slow, wet slog, an uneventful passage and a misadventure fraught with gear failures, sea sickness, injuries and fear. In extreme cases it can mean the difference between life and death.