Just a few years ago, airlines got their weather reports by telex. Pilots pored over reams of paper and compared the forecasts with their flight plans. Once airborne, they depended on radio communications and rudimentary radar to avoid bad weather.
Now, pilots download detailed flight plans and weather reports full of intricate graphics onto tablet devices. Flight dispatchers track aircraft in real time and provide up-to-the minute weather data. New generations of airplane radar systems allow for easy in-flight adjustments.
The result? Fewer of the bumps, jolts and spilled drinks that have been a part of flying ever since the Wright Brothers.
“The secret sauce is how you use the information,” said Tim Campbell, senior vice president for air operations at American Airlines. “Fundamentally, it’s only a forecast and it’s still weather.”
Weather accounted for 36 percent of all airline delays in 2013, down from 50 percent in 2003, according to theBureau of Transportation Statistics.
“Our seven-day forecast today is about as accurate as a three-day forecast was 10 years ago,” said Michael Pat Murphy, a meteorologist at the Aviation Weather Center in Kansas City, Mo., a unit of the National Oceanic and Atmospheric Administration.
Meteorologists at the center provide detailed weather reports to the airline industry. Every two hours, they hold a conference call to give airlines and the Federal Aviation Administration’s central command center their latest storm and rain predictions. They also come up with a global forecast every six hours that is used by airlines around the world, and they are responsible for issuing alerts for dangerous conditions like lightning storms or icing in the United States.
There are about 50,000 flights in America every day, and around 8,000 jets in the air at any given time. It does not take much to disrupt operations. A storm over the northeast corner of Pennsylvania — where much of the air traffic from New York’s three big airports flows — can cause widespread delays all the way to the West Coast.
Turbulence poses a particular challenge because it cannot be seen by satellite or radar. But meteorologists use complex weather models as well as reports from pilots to predict areas of heavy turbulence. Sensors on some planes operated by Alaska Airlines, American Airlines and Delta Air Lines can automatically relay turbulence information to dispatchers to look for alternative routing for later flights.
An average of 36 people have been injured as a result of turbulence each year since 2002, according to the F.A.A., which records only the most severe cases. This month, an Allegiant Air jet hit a patch of rough air over Florida, injuring three people; the experience felt “like a bad roller coaster ride,” one passenger recounted, with people jumping up and down as if it were a scene from a movie.
“We can reliably identify potential areas for turbulence,” said Tom Fahey, who heads a team of 27 meteorologists at Delta. “Where it gets difficult is identifying exact locations at a given instant, since by definition turbulence is in motion.”
Some experts also believe that the frequency and intensity of turbulence could increase because of climate change. A study from professors at two British universities, Paul Williams of the University of Reading and Manoj Joshi of the University of East Anglia, found that by the middle of the century the strength of turbulence over the North Atlantic could increase 10 to 40 percent.
“Our results suggest that climate change will lead to bumpier trans-Atlantic flights,” the authors wrote in a paper published last year.
Getting the weather right is just half the story. Planes are also delayed by congested airspace, limited runway capacity or mechanical problems, even on clear days. Just 76 percent of all flights landed within 15 minutes of schedule in the 12 months through June, down from 79.4 percent a decade ago, according to the Transportation Department.
And airlines can still get the weather wrong. On Aug. 9, forecasters thought a storm over Denver’s airport would be short-lived. The storm lasted three hours; planes that were holding in the air were getting low on fuel and were diverted to nearby airports in Colorado Springs, Cheyenne, Wyo., or Provo, Utah.
Cleaning up the mess after such storms and getting planes and crew back on schedule and passengers to their intended destinations takes time, something Gene Kim, the dispatch director at Southwest Airlines, calls the “two-day hangover.”
“Forecasting weather is a very unforgiving practice,” Mr. Kim said. “When you miss the mark, a lot of people come barking at you.”
Southwest Airlines recently outfitted 87 of its 600 Boeing 737s with sensors that measure water vapor in the air to determine the location of fog, cloud formation and cloud ceilings. Hawaiian Airlines is developing real-time weather maps in the cockpit to give pilots access to the same detail of information available to dispatchers on the ground.
Airlines are also putting more emphasis on anticipating events, not just reacting to them.
When Hurricane Sandy came up the East Coast in 2012, airlines started to cancel flights several days in advance, giving passengers ample warning, rebooking them on later flights or offering refunds.
“Our goal is when you have to hit the customers and cancel a flight, hit them early, hit them when they are at home and give them rebooking options early,” said Dave Holtz, who heads Delta’s operation control center.
The forecasting process is constantly evolving. The National Weather Service uses a supercomputer in Reston, Va., known as Tide, that has a capacity of 213 teraflops — meaning it can make 213 trillion calculations a second. The computer was recently upgraded from 90 teraflops, and the agency is seeking funding from Congress to increase it to 1,950 teraflops.
Meteorologists also expect that new satellites, to be launched starting in early 2016, will give them a better reading of low-ceiling clouds and low-visibility environments, one of the biggest causes of fatal accidents for private pilots and general aviation.
Places like San Francisco might benefit. Morning fog often restricts traffic to a single runway, instead of two. Getting a more precise sense of when the fog will break would help airlines know when to direct flights to San Francisco without risking delays.
“The more observation, the better the model,” Steve A. Lack, a meteorologist with the National Weather Service, said of the new generation of satellites. “And this one is a game-changer.”