Forth Worth, Texas ? Airline meteorologist Mark Mabey stares at four computer screens on his desk. They are filled with data, charts and radar images. All seem to suggest a different potential for thunderstorms – the airlines’ enemy during the hectic summer travel season.

He rubs his chin and sighs, then walks to a large bank of windows. His eyes scan a mass of menacing clouds in the distance. He is thinking about the forecast he is trying to generate for his carrier, American Airlines.

“This isn’t an easy call,” says Mabey, lost in thought as he looks back toward his computers. “I might have to rely on intuition.”

On this particular Monday last month, Mabey was worried about more than nasty letters or phone calls of the kind television or radio meteorologists get for predicting a sunny weekend that turns out to be a washout. The quiet, little-noticed work that Mabey and dozens of other airline meteorologists perform has huge financial and operational consequences and can affect the travel plans of thousands of passengers.

Operational consequences

Relying on computer models, government forecasts and radar, Mabey’s predictions will dictate how American executes its schedule, files flight plans for aircraft arriving from as far away as India and loads fuel on each jet.

A good forecast will save the airline cash and grief. A bad one could lead to an operational and public relations debacle – just ask executives at American and JetBlue Airways, each of which have endured recent weather-related mishaps that left hundreds of passengers trapped on planes for hours.

As Mabey walks about his office, he mulls his options.

A forecast of a decent chance of thunderstorms will force dispatchers to add fuel to planes so that the aircraft might be able to circle until the weather clears. That would help the carrier prevent costly diversions to alternate airports.

But extra load is heavy, requiring more fuel to be burned to keep a plane airborne. With oil prices at all-time highs, airlines are doing everything they can to cut back on their use of fuel.

It’s a difficult balancing act, especially in an industry that has razor-thin profit margins after years of billion-dollar losses. And during the busy and congested summer travel season, the stakes are even higher: Planes are packed, and airlines are battling record delays at airports across the country.

“Meteorologists start everything around here,” said Monte E. Ford, a senior vice president and the chief information officer at American.

The first question Ford asks his assistants each morning is about the day’s weather outlook.

“A big part of what we do is dependent on weather,” he said.

Staffing changes

In 2003, American eliminated its 21-person meteorological team and hired outside contractors. Several of the airline’s meteorologists, including Mabey, eventually got jobs with Weather Services International, the firm American ultimately hired to generate its forecasts.

Other airlines have made similar cuts, saying they have reduced costs and that they get better forecasts from third parties. Low-cost carriers such as JetBlue generally have shied away from the expense of employing in-house weather staffs. At least two carriers, Delta Air Lines and Northwest Airlines, have kept their teams despite going through recent bankruptcy reorganizations.

The work of airline meteorologists, whether as airline employees or at contractors, has historically generated little public attention. But recent incidents have put them in the spotlight. American’s meteorologists – not including Mabey – didn’t predict the duration of thunderstorms that whacked the carrier’s Texas hub in December and April, forcing American to divert nearly as many flights each day as it did on Sept. 11, 2001, American executives said.

Daily decisions

On the iffy Monday last month, Mabey had been wrestling with the forecast since he started his shift at 6:30 a.m. His computer models predicted various outcomes: no chance of thunderstorms, a risk of thunderstorms, a 40 to 60 percent chance of thunderstorms and a near guarantee of scattered to severe thunderstorms. Radar images hinted at potential thunderstorms east of Dallas, and government forecasts put the chance at about 30 percent.

Mabey said he didn’t want to simply report that there was a good chance of thunderstorms. He wasn’t convinced they would show up, thinking it would not get hot enough “to set them off.”

“You don’t want to be too pessimistic because then you burn fuel,” he said. “But if you are too optimistic, you can get burned, too. The tough part about today is that you don’t see anything now, really. But you have to plan for two, three, four hours down the road.”

About noon, just as he was finishing his forecast, he looked at another computer model and radar images of rain east of Dallas. He heard a computer beep behind him. He turned and watched as the computer’s monitor began to map lightning strikes near Dallas. “Hmm,” he said several times before heading to the windows to take a peek at the building storm clouds. “This is the kind of torture you put yourself through.”

By 1:30 p.m., he decided to parse the forecast carefully, writing that the storms should remain near Dallas but that he “can’t rule out” that they might pop up around American’s hub at nearby Dallas-Fort Worth International Airport.

That afternoon and evening, as thunderstorms rattled Dallas, only a few small ones developed close to the airport. Lightning forced workers to shut the ramp for about half an hour.

There were no diversions.