By David Adams
MIAMI (Reuters) - The science of predicting hurricanes has come a long way since Katrina caught New Orleans officials off guard 10 years ago.
A range of technological advances, from a new generation of satellites to supercomputers and unmanned drones, promises more-accurate forecasts that would increase public officials' confidence in weather experts' advice. In turn, that could lead to a more urgent response that would save lives.
If authorities were quicker to heed warnings about the devastating potential of Katrina before it made landfall in Louisiana on Monday, Aug. 29, 2005, some of the nearly 1,800 lives that were lost may have been saved, forecasters speculate.
More than two days before the costliest storm in U.S. history struck, government forecasters at the National Hurricane Center in Miami put out an advisory showing New Orleans could take a direct hit. But it was not until 36 hours later that the city issued mandatory evacuation orders, as experts had urged, leaving many at risk from flooding after levees broke.
Max Mayfield, the center's director in 2005, recalls placing an urgent call to New Orleans' then-mayor, Ray Nagin, with a plea to take urgent action on Saturday evening.
"I wanted to go to bed that night knowing we had done as much as we could to spare lives," Mayfield said.
Nagin, currently serving a 10-year prison sentence on bribery and money laundering charges related to Hurricane Katrina contracts, was not available for comment.
Kathleen Blanco, Louisiana's governor at the time, said Nagin was slow to issue the mandatory evacuation order but recalled how he had joined her on Saturday in urging voluntary departures.
"To be fair, we had gotten the majority of people out," she told Reuters, "but Max Mayfield did a very valuable service to give us a call and spur us all on more avidly."
Blanco recalled a false alarm in 2004 when Hurricane Ivan appeared to threaten New Orleans, prompting an evacuation that choked highways. Stranded drivers were irate when no storm arrived.
Because of past errors like these, Mayfield said, city officials were overly concerned about the cost of shutting businesses and schools.
"It's really important to get the forecast right, but it's also really important to communicate the certainty of the forecast so there aren't those 36-hour lags," said Peter Neilley, head of global forecasting services of The Weather Channel, which is owned by The Weather Co.
Still, most experts agree there is no such thing as 100 percent accuracy in forecasting hurricanes, regardless of improvements in data collection and raw computing power.
"The atmosphere is fundamentally chaotic and unpredictable," said Jeff Masters, a private forecaster with The Weather Co's Weather Underground division.
"There's a limit to how much certainty we can have in the modeling."
While forecasting the track of hurricanes has improved steadily over two decades, advances in gauging a storm's intensity have lagged, experts say.
Government forecasters struggled this week to predict the strength of Tropical Storm Erika as it swept through the Caribbean toward Florida because mountainous islands and hostile winds interfered with the weather system.
In 2005, forecasters were notably slow in detecting Katrina's sudden intensification, said Mark DeMaria, the National Hurricane Center's technology and science chief.
In response, the National Oceanic and Atmospheric Administration began a project in 2009 to improve hurricane forecasts by 50 percent by 2019.
NOAA said it was starting to see progress because of major advances in computer modeling. Real-time observations of ocean conditions, such as sea surface temperature and height, are improving as well.
Starting next year, new satellites known as GOES-R will feed back images more quickly and with four times the resolution of earlier generations, DeMaria said.
GOES-R satellites transmit infrared thermal imagery to detect sea temperature, which helps determine the intensity of storms, which draw energy from the water's heat.
NASA also began construction this month of suitcase-sized "microsatellites" capable of measuring winds in and near the eye wall of hurricanes.
NOAA and NASA are experimenting with an unmanned aircraft, Global Hawk, to provide better weather readings, while drones are now being used to get closer to the interior core of a storm than traditional Hurricane Hunter planes can.
Also, Congress funded an upgrade of the National Weather Service's IBM supercomputer system after Superstorm Sandy in 2012, bolstering capacity to crunch data by 25 times.
"If Katrina occurred today," said Neilley, "every aspect of the process ... hopefully is a lot better."
(Editing by Frank McGurty and Lisa Von Ahn)