FDs are still very much with us. In fact, the FD is still the "official" source of winds and temperature aloft forecasts.
Today, however, pilots can sit down at their computers to consult maps like the one in Figure 2, which shows the winds forecast at 6,000 feet for roughly the same time as the Figure 1 forecast.
You see at a glance that winds over southeastern Iowa are forecast to be from the south, maybe the south-southwest, at speeds from 30 to 40 kt. Even more important, you see that winds are moving in a tight counterclockwise circle over Iowa. This indicates that a strong low-pressure area is forecast to be over Iowa and could be stirring up some wild weather in addition to the brisk winds at 6,000 feet.
Wind forecasts like Figure 2 are just one of the many new weather products that have become available to pilots since the mid-1990s, when the FAA, the National Weather Service (NWS), and several research institutions began working more closely together under the FAA's Aviation Weather Research Program (AWRP).
The whole idea was - and still is - to bring together top-notch atmospheric scientists and aviation weather forecasters to work with the FAA in finding answers to specific problems, such as improving icing predictions.
While new forecast formats are the most obvious result - to pilots - of the program's work, its goals go far beyond making weather information more user-friendly.
On its Web site, AWRP says the program aims "to increase the scientific understanding of atmospheric processes that cause the development of hazardous weather, which in turn, impacts aviation. The research is aimed toward generating weather observations, warnings, and forecasts that are more accurate and more accessible."
Gloria Kulesa, who heads the program for the FAA, says research is directed toward weather problems that are both important and likely to be solved or mitigated by scientific research that can be done now.
The focus is on helping pilots, air traffic controllers, airline dispatchers, and others who use the products, not on research for the sake of research. Also, Kulesa says, "We don't wait for a product to be 'done'; we get it out into the hands of the decision makers." From the beginning, the AWRP has worked to remove, or at least lower, bureaucratic barriers between scientists and forecasters.
The key forecast problems being addressed include in-flight icing; turbulence; ground deicing; thunderstorms and their associated dangers; and ceiling and visibility.
In-flight icing is currently the FAA's top weather research priority, Kulesa says. "Each year icing is the number one cause of aircraft accidents, mostly general aviation but sometimes commuter aircraft. The problem is still the accuracy of the [forecasts]; we're striving for greater accuracy." A major complaint about today's icing forecasts is that they often cover too wide an area; in other words, there are too many false alarms. The research goal is to reduce false alarms without compromising accurate icing forecasts.
All too often today alerts for turbulence are issued after a pilot reports a bumpy ride, or worse. Because such pilot reports are subjective, they don't supply forecasters with the kind of hard data that could be fed into computer forecasting models. Today's turbulence reports depend on the kind of aircraft - those aboard a Boeing 747 would hardly feel turbulence that could violently shake a Cessna 152 - and the pilot's subjective evaluation of the aircraft's reactions. One research goal is to begin equipping aircraft with sensors that would measure turbulence and automatically report it. Such reports would help build a good turbulence database that researchers could match with meteorological conditions at the time. The ultimate aims are to produce timelier and more accurate reports and forecasts of turbulence, and to develop user-friendly turbulence products.
A program called Weather Support to Ground Deicing Decision-Making (WSDDM) is in operation at the New York City-area airports. The program was prompted by mid-1990s research into several air carrier takeoff accidents caused by icing. The scientists discovered that whether snow is light or heavy - as determined by visibility - isn't a good guide to deicing. Instead, how wet the snow is, along with temperature and winds, determine what concentrations of deicing and anti-icing are needed. In tests of the WSDDM system, airport managers have also learned that it helps them to decide when to call out the chemical spreaders and plows needed to keep runways and access roads open.
Thunderstorms cause crashes and are also the main cause of flight delays during the spring and summer, Kulesa says. Accurate forecasts of where thunderstorms will be and how strong they'll be in an hour or two will allow pilots, controllers, and airline dispatchers to plan routes to avoid storms instead of having to scramble to make last-minute diversions as they often do now. In September 2001 the National Weather Service began issuing National Convective Weather Forecasts. Figure 3 shows part of one of these maps, which show current and predicted locations of thunderstorms. Researchers who developed this new product are now working on improving it.
Despite the improvements in most kinds of weather forecasting in recent years, predictions of ceiling and visibility still often turn out wrong. In 2001 forecasters began testing methods of predicting ceiling and visibility that AWAP researchers developed for San Francisco International Airport. Now, researchers are looking for ways to use the techniques that they devised for San Francisco at other airports around the country.
Over the next few years pilots can expect not only more accurate weather forecasts, but also graphic and text presentations that will make it easier to understand the forecasts and apply them to flights. No matter how good and easy to understand forecasts become, however, pilots will always have to understand enough about weather, their aircraft's capabilities, and their own abilities to decide whether it's safe to take off or continue a flight.
Web Sites
Web sites with more information
Aviation Weather Research Program home page www.faa.gov/aua/awr/index.htm
NWS Aviation Weather Center http://aviationweather.noaa.gov/ index.html
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