How accurate is hurricane forecasting? Meteorologists explain.

The Atlantic hurricane season lasts through Nov. 30.

October 24, 2024, 10:00 AM

Hurricane forecasting has made tremendous strides in recent decades, but there is still a disconnect when it comes to the general public's understanding and awareness of forecasting elements, according to experts.

The predictions made for two of the most recent powerful tropical systems -- Hurricane Helene and Hurricane Milton -- were near-precise, Marshall Shepherd, director of the Atmospheric Sciences Program at the University of Georgia and former president of the American Meteorological Society, told ABC News.

Modern-day track forecasts released by the National Oceanic and Atmospheric Administration tend to be extremely accurate, Shepherd said. The intensity forecasts, while a bit more challenging due to the ever-changing characteristics from the inside of the storm and how they interact with the surface of the ocean, are also much more accurate than in decades past, Shepherd said.

"Small changes in atmospheric conditions can have a large impact on forecasts," according to the NOAA.

Hurricane Helene GeoColor satellite, Sept. 26, 2024.
NOAA

Two of the key metrics of forecasting -- the "cone of uncertainty," which represents the probable track of the center of a tropical cyclone, and the Saffir-Simpson Hurricane Scale, which ranks the intensity of the hurricanes wind speeds -- have gotten "immensely better" over the last 30 years, Paul Miller, an assistant professor of coastal meteorology at Louisiana State University, told ABC News.

Recent research has helped to lower model forecast errors for both track and intensity across all lead times, which have resulted in more precise forecasts by the National Hurricane Center, according to the NOAA.

Technological improvements have also improved accuracy, the experts said.

When Hurricane Andrew hit Florida in 1992, the technology available at the time could not adequately forecast the storm, which struck South Florida as a Category 5 storm, Eric Blake, senior hurricane scientist at the National Hurricane Center, told ABC News in 2022. Statistics, along with "persistence and forecaster intuition," were the main tools meteorologists used at the time, Blake said.

Canal Street is flooded a day after Hurricane Katrina blew through, Aug. 30, 2005, in New Orleans.
Chris Graythen/Getty Images

But the "biggest change" has been the improvements in computational power, Miller said.

Now, advanced satellite imagery allows forecasters to see inside a hurricane every 30 seconds. Aircrafts manned by hurricane hunters fly into the center of the storm to collect radar and wind data. New models use the current structure of the storm to forecast how it may behave in the future, Miller said.

"It's really impressive to go back and look at the accuracy of forecasts since the late '90s, or even back to Hurricane Katrina," Miller said.

Meteorologists' confidence on storm prediction is measured by "forecast uncertainty," according to the NOAA. Storms that are challenging to predict are characterized by "high uncertainty," but when models seem to agree on a possible outcome, the forecasts are characterized as "low uncertainty."

The NOAA’s Atlantic Oceanographic and Meteorological Laboratory is studying the environmental factors that influence tropical cyclone intensity forecasts to further improve predictions, according to the agency.

Aerial view of destroyed houses in Port St Lucie, Fla., after a tornado hit the area and caused severe damage as Hurricane Milton swept through Florida, Oct. 11, 2024.
Miguel J. Rodriguez Carrillo/AFP via Getty Images

But even as accuracy improves, meteorologists worry about the message getting across, especially because hurricanes are a "multi-hazard phenomenon," Miller said. While all attention is on the system itself, it is difficult for those outside the track to fathom what the storm could bring to their area, Miller said.

Hurricane Helene caused devastating flash flooding in Appalachia near Asheville, North Carolina, while Hurricane Milton spurred catastrophic tornadoes in Southeast Florida -- a region far outside the storm's track -- hours before the system even made landfall.

Heavy rains from hurricane Helene caused record flooding and damage, Sept. 28, 2024, in Asheville, N.C.
Melissa Sue Gerrits/Getty Images

Excessive rainfall and flash flooding was forecasted for days before Helene moved into the Asheville area, as were the increased likelihood of tornado activity that struck South Florida ahead of Milton.

"I don't think the average person knows how to translate what excessive rainfall means," Shepherd said, despite the terminology being "meaningful" to the meteorology community.

"I think that the severity of those tornadoes is really what caught people off guard," Shepherd continued. "I think we were all conveying the threat of tornadoes."

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