Instead of having to deal with the usual imprecise weather predictions, a state-of-the-art forecasting technique can give pilots an extra hour of lead time on likely thunderstorm formation.

Key to the new technique, which has piqued the interest not only of the FAA, but also the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration (NASA) Langley Research Center, is a better understanding of what's happening in cumulous clouds, which create most thunderstorms. NASA, in fact, has been funding the main research effort, which has been led by atmospheric scientist John Mecikalski at the University of Alabama-Huntsville.

Four years ago when he was still with University of Wisconsin, Mecikalski tells sister publication Air Safety Week that he first realized that two already established technical capabilities of reading satellite signals could be combined to better understand where and when thunderstorms start. One such capability was the ability to identify cumulous clouds. The second was the ability to track the clouds by comparing satellite images that are generated every 15 minutes or so. By putting the two capabilities together, it's possible to see how the clouds and the updrafts within them are growing.

When these updrafts, drawing warm humid air up from ground level to about five to 10 miles, become "relatively large and sustained," that's when thunderstorms start. And by studying a succession of satellite images in the manner described by Mecikalski, it's possible to quantify updraft size and do real-time monitoring of likely thunderstorm formation. In most cases, a brewing thunderstorm can be seen nearly an hour ahead of time.

There's also an analogy here to tornado forecasting, Mecikalski points out. Just as he and his colleagues have been looking at updrafts in cumulous clouds to forecast thunderstorms earlier, other researchers are monitoring lightning strikes in hopes of getting more lead time on where tornados are about to touch down.

In the meantime, the important folks at both NASA and the FAA believe that Mecikalski is really onto something that will help aviation safety.

"What John is doing is very significant because convective weather is the primary constraint on aviation efficiency and capacity," says another atmospheric scientist, John Murray, who also happens to be Mecikalski's funder at NASA's Langley Center. Particularly in warmer weather, and around the country's busiest hubs, such as Hartsfield-Jackson Atlanta Int'l Airport (ATL) or Chicago's O'Hare Int'l (ORD), bottlenecks and delays occur fairly quickly and frequently when it appears that one potential thunderstorm after another is rolling in.

As the project manager for NASA's Advanced Satellite Aviation Weather Products Project, Murray and his staff team regularly partner with staff at FAA's Aviation Weather Research Program, to provide them with the latest expertise in using satellite data. Mecikalski's product is bound to be a big help to FAA and their national air traffic control (ATC) system, Murray tells Air Safety Week, mostly because satellite data now becomes a "surrogate" for radar signals.

FAA readily agrees with the potential benefits of Mecikalski's work to aviation safety. Although the work still seems "very preliminary," the agency is also "very excited about it," FAA spokesman Paul Takemoto says. For a long time, agency personnel have had to rely mostly on ground-based radar signals, which have a limited range and which don't reach into all regions of the national airspace. But if they want more of a region-wide view of what's going on, FAA staff have to assemble the radar data together into a rather patchy mosaic. Satellite signals, on the other hand, which provide a much broader scan of the earth's atmosphere, can be combined with radar signals to greatly increase predictability.

Moreover, ATC now really just detects where the storms currently are, but it's more important to predict where they're going to be, Takemoto says. A system like Mecikalski's that can predict storms an hour in advance with 65 percent accuracy has great potential for not only improving air safety, but saving the aviation industry a great deal of money.

Echoing what Takemoto says about the broader range of satellite signals, NASA's Murray agrees that the older weather products are limited by the available radar horizon, leaving "huge gaps" in certain pockets in the national weather map. Until now, the state of aviation weather forecasting has taken on the characteristics of a "detect and manage" type approach, and not a more predictive approach.

The evaluation of Mecikalski's technique for FAA is actually going to be done at the Massachusetts Institute of Technology's (MIT) Lincoln Laboratory. There, Haig Iskenderian, who is on the technical staff with the laboratory's weather sensing group, says Mecikalski's technique certainly has the potential to "minimize the weather surprises."

Moreover, it's really about controlling air traffic in the crowded U.S. skies, particularly the eastern part of the country, he adds. The better the warnings that FAA staff get about where and when the storms will be, the better their decisions will be about routing aircraft. Ultimately, this translates into fewer disruptions in the national airspace system, Iskenderian tells Air Safety Week.

The MIT evaluation should begin in earnest later this year, and wrap up sometime in 2007, FAA's Takemoto adds.

Mecikalski says the next phase of his work will focus on getting an additional 1 to 1.5 hours lead time in predicting lightning strikes, which will especially help NASA's space shuttle program.

"Aviation Applications for Satellite-based Observations of Cloud Properties, Convection Initiation, In-flight Icing, Turbulence and Volcanic Ash," is in the January edition of the Monthly Weather Review, which is published by the American Meteorological Society.

Contacts: John Mecikalski, University of Alabama-Huntsville, (256) 503-4921, john.mecikalski@nsstc.uah.edu; Haig Iskenderian, MIT Lincoln Laboratory, haig@ll.mit.edu