Like anyone who studies weather, Steven Goodman could be considered a voyeur of sorts. For him this often means getting a charge out of watching lightning in and around the Gulf of Mexico.

But Goodman eyes nature's electricity from the safety of his office at the Global Hydrology and Climate Center in Huntsville, Alabama, where he monitors real-time radar images. Watching from afar, day after day during the winter of 1997-98, Goodman noticed there was a whole lot of lightning around the Gulf of Mexico -- more than just about anywhere in the world.

"This struck me as weird," Goodman says.

He checked around. His colleagues thought it was a bit unusual, too. Then he heard about a potential culprit.

"It wasn't until I heard all the fuss about El Niño, and 1997-98 being the biggest event since the 1982-83 event, that we decided to dig into this event in more detail," Goodman told SPACE.com.

So he and some colleagues pored over a decade of ground-based lightning data, plus new satellite measurements from NASA's Tropical Rainfall Measuring Mission. They found that El Niño, a periodic warming of the tropical eastern Pacific Ocean, can nearly triple the number of wintertime hours of lighting in and around the Gulf.

"What we discovered was large year-to-year changes in thunderstorm activity that seemed to be tied to this El Niño in particular, but also to three of the past four El Niños," Goodman said.

A paper detailing the research appears in the February 15 issue of the journal Geophysical Research Letters.

Fueling the jet stream -

El Niño contributes to the bevy wintertime thunderstorms by pumping energy from a warmed tropical Pacific high into the atmosphere, where it forces the jet stream -- a river of fast-moving, high-altitude air -- to alter course. Storms are known to track along the jet stream, which forms a barrier between cool northern air and warm, moist tropical air.

"The air is usually more unstable due to the influence of El Nio. Down here, that's what it takes to create thunderstorms."

Normally, the winter jet stream dips no farther south than Virginia. During El Niño, however, it can be kicked into Alabama, and even out over the Gulf of Mexico. A sharp contrast is created between the warm Gulf waters and the frigid Arctic air that huddles up to the northern boundary of the jet stream.

And stormy weather loves a contrast.

So much so that the number of days with lighting around the Gulf, during winter, jumps from 15 or less in La Niña years (the opposite of El Niño) to as much as 33 when El Niño is in charge. Moreover, the total hours of wintertime lightning can go from less than 50 to as much as 138 during El Niño years.

The greatest change is out over the Gulf waters.

No surprise in Mobile -

The study results were no surprise to Gary Beeler, warning coordination meteorologist at the National Weather Service in Mobile, Alabama -- smack in the middle of the study area. Beeler already knew that El Niño forces the jet stream, and the cold air that comes with it, farther south.

"The air is usually more unstable due to the influence of El Niño," Beeler said in a telephone interview. "Down here, that's what it takes to create thunderstorms."

Beeler said a normal winter yields an average of 2.2 days each month with thunderstorm activity around Mobile. In the winter of 1997-98, when he recalls the jet stream being "right on top of us," each winter month had four or more days with thunderstorms.

And this winter? -

"It's been the quietest severe-weather period that I can remember since 1994," Beeler said. He credits La Niña for making it so. He also said space-based reconnaissance has helped researchers "tremendously in the last four or five years" to grasp the influence of the El Niño/La Niña cycle.

Hugh Christian, who runs the Global Hydrology and Climate Center where Goodman works, said the study helps confirm suspicions about how the atmosphere responds to long-term phenomena like El Niño. But, he adds, there's still "lots and lots and lots" of work to do before such knowledge will help improve long-range forecasts.

The future: better tornado forecasts -

Christian said the same space-based lightning monitoring used in Goodman's study could one day be used to peer more effectively into the heart of a storm and improve severe weather forecasts. Lightning, Christian explains, is a good indicator of a storm's power and intent, hinting at the type of internal processes -- like rapidly rising air -- that can lead to severe tornadoes.

But current space-based measurements of lightning rely on periodic passes by satellites in low Earth orbit. The same instruments aboard a satellite in geosynchronous orbit -- a fixed relative perch above the planet -- could supply continuous real-time data.

"The idea is that we can use light as an indicator of storm activity," Christian said. "Then we'd have a very powerful tool to look at severe weather" and provide real-time forecasts.