Wx Watch: ADDS Upgrades

Better weather information, moving from experimental to legal

October 1, 2005

Faithful readers of "Wx Watch" will recall that I've referred to the Aviation Weather Center's (AWC) Aviation Digital Data Service (ADDS) Web site many times in the past. ADDS provides many valuable briefing products, and the AWC is constantly improving the site to make it more valuable and cutting edge. I visited the AWC in Kansas City, Missouri, recently, to get a better look at some of the new products we can expect to see on the ADDS site in the next two years or so. My guides were Jack May, the AWC's director, and Larry Burch, deputy director and chief of the international operations branch. (Interesting aside: In 1986, Burch served as the lead forecaster for the around-the-world flight of Burt Rutan's Voyager.)

While pilots best know the AWC via its extremely popular ADDS Web site, the center creates several other products that we're all aware of. For example, airmets, sigmets, convective sigmets, and area forecasts are all generated here. So are the Current Icing Potential and Forecast Icing Potential (CIP and FIP, respectively) charts, the National Convective Weather Forecast (NCWF) charts, the Collaborative Convective Forecast Product (CCFP) graphics, and significant weather prognosis charts. It's a very busy place indeed — and especially so on the day of my visit, when Hurricane Katrina was making landfall in southern Florida. This made meteorologist Scott Tansey's tropical desk a frantic one at times, complete with nationwide conference calls on the hurricane's progress.

In the day-to-day scheme of things, it's the ADDS Web site that gets the most attention. With its whopping 4 million hits per day, ADDS is perhaps the prime source of preflight weather information for most computer-savvy pilots.

That by itself is impressive. But the site serves another important function. It's a gateway between the meteorological research community and end users. If a creative new product comes out, it makes its debut on ADDS' experimental or testbed pages as part of its proof-of-concept journey to operational status. And it's there that we can see some exciting previews of what's to come.

Before we delve into the details of some of the new experimental products, let's establish some definitions that refer to the authorized use of ADDS Web site products. The first has to do with the distinction between restricted and unrestricted use. If a page is marked as restricted — as, say, the CCFP is defined as being restricted to use by meteorologists and dispatchers — this means that pilots cannot legally use it for decision-making purposes. Unrestricted products carry no such warning, and can be used by all who call it up.

Then there's the matter of a product's being supplemental or primary. Supplemental means the product is intended for use by pilots for enhanced situational awareness only and, if used, used in conjunction with one or more primary weather products. Primary-use products meet all regulatory requirements and safety needs for use in making flight-related decisions.

It's all part of the strategy to avoid liability exposure, as well as prevent pilots from using products that they may not fully understand, or may misinterpret altogether. Of course, none of this can prevent pilots from consulting restricted/supplemental products as part of the mandate to "become familiar with all available information" concerning a flight, as defined in FAR Part 91.103. Just don't use them to make go/no-go or other weather-related decisions.

Bearing all that in mind, here's a brief review of some of the products on deck at the ADDS Web site. You can call some of them up on the site's testbed domain online.

NCWF-2. The current NCWF is a completely automated product that shows the projected path and intensity of thunderstorms, shown as a looped image. A supplemental product, it works well once storms have formed, but can't predict where new storms will form out of clear air. NCWF-2 is aimed at predicting this sort of popcorn-type convection that comes about as the day heats up. Its computer-model algorithms are still in development.

CIP and FIP. The Current Icing Potential and Forecast Icing Potential products, which are restricted and supplemental, do good jobs of identifying cold cloud tops — and by extension, areas of anticipated icing — but they currently do not refer to the intensity or type of icing. They only convey a relative chance of icing's occurrence, so a FIP's 90-percent plot only means that there's a relatively higher degree of icing than, say, a 50-percent potential. An upgrade to show severity levels — light, moderate, and severe — is due to be introduced in 2007.

Graphical Turbulence Guidance (GTG). This experimental product is also due for an important upgrade. The current GTG begins reporting turbulence at 20,000 feet, which is of little use to general aviation pilots flying below that altitude. Soon, said May, the GTG will show turbulence at altitudes as low as 10,000 feet. Low-altitude turbulence is difficult to predict because of terrain influences and other chaotic elements that computer models have trouble assimilating. Still, researchers are hard at work to improve low-altitude performance.

Graphical area forecasts. Today's area forecasts plot six hours' worth of aviation hazards. They also come out in text form (limited to 3,900 characters, by the way). But current area-forecast plots cause huge areas of adverse weather to appear, since all six hours of anticipated weather must be drawn in one chart. The Graphical Area Forecast Experiment (GFAX) will let pilots click or mouseover buttons that give five three-hour outlooks into the future, then two more six-hour views of predicted weather. It's scheduled for primary status sometime in 2007 as well.

Graphical airmets (G-Airmets). Like the GFAX, the G-Airmet will feature mouseover buttons and three-hour snapshots into future anticipated airmet weather. You can select the hazards you want to explore, then mouseover the time frames that concern you. This way, you can watch as a fog layer burns off — or not! — and see if turbulence or icing will increase, decrease, stay the same, or shrink or expand in areal coverage.

Flight-path tool. ADDS' flight-path tool, which can show the weather along a defined route, is set to change to include a downloadable application that resides on your computer. It will be able to store customizable settings, routes, and weather products (i.e., airmets, METARs, TAFs, winds aloft, CIP/FIP) so that you won't have to define new settings at the Web site each time you fly.

While it will be great to have these new briefing tools, there are regulatory implications that have yet to be addressed. Technological advances, be they in weather briefing or avionics, are happening at a pace that government can't hope to match. "The regulations don't acknowledge things like the graphic changes that will be happening to ADDS," said May. "But if they're going to be primary briefing elements, then the pilot knowledge exams — for starters — will have to be changed to make sure pilots know how to interpret them. Right now, for example, the only mention of any of our recent products by the FAA is that of the NCWF — in the Aeronautical Information Manual" (see Chapter 7-1-4).

Meanwhile, back at the forecast floor at AWC, all seven workstations (area forecast eastern region; area forecast central region; area forecast western region; CCFP; convective sigmet; tropical; and significant weather graphics) are humming. Andy Fischer is updating the most recent of the central region's daily tally of 86 total convective sigmets. Pat Murphy is on a conference call with airline meteorologists, preparing for the next CCFP graphic. And supervisor (and eastern region lead forecaster) Paul Fike is preparing the next airmet. Using multiple flat-screen displays, he can call up a wide range of model input, satellite imagery, and other data to make his decisions.

One of the most important datasets is pireps. "Without them, it's like having a baseball game without the scores," said Burch. "You know, 'Cleveland 3'...." And then he goes silent to emphasize the gap in knowledge exemplified by the other team's missing score. "Pireps are so important to forecasters, and we can't get enough of them. Even if someone calls in a pirep of clear skies and no turbulence, that's valuable to us," said Burch. "It helps us verify if our forecasts are right or wrong, and believe me, we use them." The AWC and AOPA ASF together encourage pireps under AOPA ASF's Skyspotter program, which is described on the AWC's home page.

Meanwhile, Fike is wondering whether to extend the airmet for turbulence over the northern New England states. The previous airmet called for turbulence in northern New England, but a Beechcraft Bonanza and a Baron — flying at 5,500 feet over Danbury and Meriden, Connecticut — are reporting moderate turbulence. In view of this, Fike's next airmet moves the turbulence advisory to include the southern half of New England.

He uses his mouse to rubber-band the airmet's boundaries to Long Island Sound, then rubber-bands another turbulence zone from the Ohio Valley to the mid-Atlantic states, based on airliner pireps from jets cruising over northern West Virginia and western Pennsylvania. The moment he does this, the new boundaries pop up on the ADDS turbulence display. In seconds, millions of eyeballs will see the new graphic. Pretty neat.


E-mail the author at tom.horne@aopa.org.


Links to additional information about new weather briefing products may be found on AOPA Online ( www.aopa.org/pilot/links.shtml).


ASF Online Safety Center

Be A Skyspotter®

More than 44,000 additional pilot reports (pireps) have been reported because of the more than 22,000 pilots who have taken the AOPA Air Safety Foundation's program Skyspotter.

Launched in late 2001, ASF began the Skyspotter program to improve pilot report quality and quantity. The program is co-sponsored by the FAA and the National Weather Service Aviation Center. Using graphics and animation, the highly interactive program teaches pilots about inflight weather and provides instruction on how to file pilot reports with flight service stations.

This program, free to all pilots, is available online ( www.aopa.org/asf/online_courses/skyspotter/).

Thomas A. Horne

Thomas A. Horne | AOPA Pilot Editor at Large, AOPA

AOPA Pilot Editor at Large Tom Horne has worked at AOPA since the early 1980s. He began flying in 1975 and has an airline transport pilot and flight instructor certificates. He’s flown everything from ultralights to Gulfstreams and ferried numerous piston airplanes across the Atlantic.