Fair Weather Friends

Keep these weather sources handy so you don't outrun your information.

October 4, 2007

Back in the day when 20 knots was considered blazing, a comfortable day’s run was perhaps 100 or 120 miles and trips over 200 miles were rare. Today, 200-mile “day hops” and 1,000-mile delivery passages are not uncommon. This newfound freedom, though, comes at a price. While conditions may be ideal at the beginning of a voyage, things can be very different hundreds of miles away; yet traditional sources for weather information-TV or VHF-only cover a small and localized area. The result: Yachtsmen may outrun their local weather forecast before lunch.

Fortunately, new communications options have kept pace with improved boat and engine technology. The Internet provides worldwide weather information with just a few mouse clicks; in seconds I can acquire the forecast from my dock in Miami all the way up the coast to Norfolk or down to Canc·n. The options, though, are not all alike, so it’s best to have more than one source.

NOAA’s National Data Buoy Center, for instance, gives present wind, sea and atmospheric conditions at hundreds of coastal monitoring stations and offshore weather buoys. Each station’s Web page displays an hourly report of conditions over the previous 24 hours, and provides links to regional wind maps and text versions of NOAA’s weather radio broadcasts.


For upper level winds, surface wind and wave forecasts, or satellite images, NOAA’s National Weather Service Marine Forecasts page holds dozens of links. Tide predictions are made for times of high and low water, and every half hour throughout the day. Another link shows present water levels, which are often different from tide predictions. Text versions of all NOAA weather broadcasts and animated-loop weather charts are available on this site as well, along with schedules for single sideband radio and weather fax broadcasts, and a link to the National Hurricane Center’s home page.

NOAA’s Web sites are free, but finding its wealth of information is not always easy. I add useful pages to my browser’s “favorites list for quick future access, but supplement my data with for-profit Web sites that are easier to use. These services charge a subscription fee or sell advertising on their site. Weather Underground, for example, provides local and regional radar and satellite images, marine and terrestrial forecasts, and astronomical data. This Web site also provides the best hurricane tracking information I’ve found, and its “pop-up ads disappear when you join for $5. and its sister Web sites provide alert bulletins via e-mail, voice, fax, pager or wireless Web when conditions are perfect, and Ocean Weather Inc. provides worldwide wind, wave, and sea temperature charts to the public, and additional forecasting to subscribers.


Ease of interpreting data is a major factor in your choice of sources. Reading buoys takes experience, satellite images and synopsis maps require interpretation, and Internet sources assume a certain degree of computer savvy. Then again, text forecasts on the Web are certainly convenient but rather generic, forecasting an area perhaps 50 miles square over a 12-hour period near shore, and are even less specific offshore.

Even if the technology front has passed you by, help is just a phone call away. For a surprisingly small fee, yachtsmen can have their own on-call meteorologist, providing custom-tailored information for a specific vessel, route and time. Weather Routing, based in upstate New York, was founded over 40 years ago to provide merchant ships with favorable routes to save fuel and avoid harming cargo. Today they service over 2,000 yachts, with about half their forecasts going to private vessels, the other half to shipping companies. Someone is on call 24/7, providing clients detailed weather forecasts worldwide via phone, fax, satellite or e-mail. They factor in tides and currents as well, for example, telling when to avoid Point Conception, where an atmospheric “stress curl often creates winds 10 to 15 knots higher than the waters in either the adjacent Santa Barbara Channel or Pacific Ocean.

Weather Routing does not charge to subscribe and offers free services like daily tropical weather updates and local hurricane alert bulletins, billing clients only when individualized forecasts are requested. A custom forecast is well under $100, much cheaper than replacing broken boat parts or missing an important meeting because of weather delays. Weather Routing also offers climatological reports for itinerary planning, helping skippers pick locations most likely to have favorable weather during extended cruises.


Many of the newest chart plotters display video. The Weather Channel, for instance, employs a small satellite antenna to overlay real-time weather information directly onto C-Map charts, including weather radar, wind and wave forecasts, and sea surface temperatures. NOAA text forecasts are also available, although the system requires a significant up-front investment and an annual or seasonal subscription. (Current price: $1,570 to install and activate; $700 per year or $400 per season subscription.) SkyMate offers similar weather information, obtained via satellite and displayed on a personal computer, but includes voice, fax and e-mail communications and can monitor bilge and battery levels and shorepower voltage. (It’s about two-thirds the cost of The Weather Channel, including phone and e-mail.)

Sailors are often the first consumers to benefit from technological advances. While sailboats, trawlers and the increasingly popular expedition yachts don’t cover vast distances in a day, they often stay at sea for long periods, requiring accurate weather information while offshore. Communications advances provide Internet access through cellular phones, satellite, and even HAM and SSB radios. The National Weather Service Marine Forecasts Web page mentioned earlier has the most extensive, up-to-date information I’ve found on offshore access to the Web, with dozens of links to service providers. The site also lists sources for foreign marine forecasts and the U.S. Navy’s worldwide weather information.

Given their slow speed, trawlers and sailboats are also particularly concerned with ocean currents; bucking a knot-and-a-quarter current at 7 knots is hell. While ocean current charting hasn’t kept pace with weather forecasting advancements, there are several sources for ocean current information free on the Web or through private services. Rutgers University provides NOAA satellite data of the Gulf Stream online, although reading these charts takes a skilled eye. Jenifer Clark, who’s studied ocean currents for NOAA for 26 years, interprets satellite images and sells her Gulf Stream charts to navigators. Fishermen, another group who have always sought the most modern technology, use satellite information to locate rapid changes in ocean temperature that often hold fish. Dr. Mitchell Roffer’s famous ROFFS Report shows fisherman the likely hot spots for a fee. Roffer also uses NASA’s latest ocean color imagery, factoring in water clarity and plankton density.


Satellite imagery shows water temperature boundaries to locate currents, but requires skilled interpretation and intuition to estimate set and drift. Satellite pictures are also affected by cloud cover, but at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science, researchers are using radar to measure the current in the Gulf Stream. WavE RAdar (WERA) uses much longer wavelengths than shipboard radar, and calculates the Doppler shift of returned signals to show the speed at which the water is moving. By factoring wind and wave information and triangulating data from at least two WERA sites, the system displays real-time current velocities, which yachtsmen can access on the University’s Web site.

Coastal Ocean Dynamics Applications Radar (CODAR) is a similar system employed off the coast of New Jersey by Rutgers University, and in the Santa Barbara Channel by UCSB, with real-time data posted on the Web. Universities in Maine, Massachusetts and Alaska also post CODAR observations online. CODAR and WERA reach over 100 miles from shore and measure sea state as well as current. These experimental radar systems have been mounted on ships, so given the trends in miniaturizing electronics we may soon have CODAR or WERA on yachts, allowing mariners to “see the current flowing around us.

Technology is constantly changing. The Web sites, services and organizations I’ve listed are by no means comprehensive, and a quick Google search provides hundreds more to explore. Even sites I use often surprise me with new information each time I look.

Best Weather Sites: ROFFS-Roffer’s Ocean Fishing Forecasting Service Inc.; Jenifer Clark’s Gulfstream; Weather Routing Inc.; Wilkens Weather Technologies; The Weather Channel Marine; SkyMate; Government Web sites: NOAA Marine Forecasts home page; NOAA National Data Buoy Center; NOAA National Hurricane Center; NOAA Geostationary Satellite images; Web sites: Rutgers University; University of Miami Rosenstiel School of Marine and Atmospheric Science; University of California, Santa Barbara; or Subscription Web sites: Weather Underground;; Weather Flow;;;;

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