After a two-year experimental run, an updated track forecast cone graphic moves into a starring role with theNational Hurricane Center this summer.
The new graphic, to debut whenthe first tropical storm forms, is one of several changes the hurricane center is making forthe Atlantic season that starts June 1. Members of the hurricane center's staff sat down with USA TODAY at the National Hurricane Conference in Orlando to talk about the changes.
The goal is to continue improving communications about hazards and risk with the public and emergency managers, said Michael Brennan, director of the hurricane center.
Thewidely recognized five-day track graphic– often called the "cone of uncertainty" – had been used since 2002.But it was often misunderstood.
It showed only the likely path of the center of the storm and markings along coastlines where tropical storm and hurricane watches and warnings were in effect. It did not show the full range of high winds, rain and other impacts, including inland areas under watches and warnings. Revisions to the cone have been the subject of great debate and deliberation among the hurricane science community.
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New cone graphic
The new graphic adds the inland tropical storm and hurricane watches and warnings in the continental United States, Hawaii, Puerto Rico and the U.S. Virgin Islands, shading them in with bright colors. "That's to better convey the wind risk, and better convey that hazards can extend outside the cone," Brennan said.
Thenew graphic was unveiled two years agoas an experimental tool for public comment regarding its effectiveness at communicating storm risks, said Robbie Berg, the hurricane center's warning coordination meteorologist.
"In the first year, there were questions about the legend and colors we were using, so we fixed that," Berg said. After the second year, it seemed to be generally accepted, he said.
"Being able to provide watches and warnings inland from the coast is a more representative picture," he said. The new graphic will also be provided in an interactive version, where viewers will be able to zoom, pan and save the image, he said.
The goal is to be in a continual improvement process, Berg said. "We're not going to just make a change and then sit on it again for 10 to 20 years, we want to be constantly making updates and new changes."
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Another new cone graphic will be waiting in the wings
Also launching this year is the hurricane center'slatest iteration of the cone graphic, another experimental version. The staff hopes it will do a better job of communicating risk and probability related to the storm's arrival by changing in two key ways.
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The old cone graphic and the graphic to be used this year are drawn using a set of concentric circles along the forecast track to illustrate where the center of the storm was expected to travel 2 out of 3 times, based on forecast errors over the previous five seasons.
"I don't think people really understand that well," Berg said. It was sometimes misunderstood as an indication of the storm's size, its impacts or as an absolute path for the center rather than a 67% probability.
The circles will change to ellipses in the experimental graphic, because their research has shown the flattened circles, or ovals, are more effective at illustrating potential forecast errors both along track and cross track. And it's based on a 90% probability, Berg said. That means a storm's center should move outside the ellipse only one out of every 10 times, making the cone a little larger, but lending higher forecast confidence that the center "will stay within the cone."
"We actually have higher errors in the along track direction, meaning it's harder for us to nail the speed of a storm relative to how much it might go right or left," he said. He compares it to using a GPS map to estimate your drive time on a trip. The digital map draws your path, and you generally stay along that path, maybe with a slight detour here or there, he said, but your arrival time can change a lot depending on traffic conditions.
Along a five-day forecast, if the forward speed is off by only 5 knots (5.7 mph), accumulated over 120 hours, that's a much larger displacement between when the storm was forecast to arrive and when it actually arrives, Berg said. Tests on the new project show "a much better representation of what the actual storm may do."
Communicating the risks
All of the products are getting "a lot better," said John Cangialosi, a senior hurricane specialist at the hurricane center. But impacts are always going to fall outside the "cone."
"The bottom line is we keep telling people you can't use this one (map) alone," Cangialosi said. "We need you to focus on the whole big picture."
That's been part of the motivation behind developing the storm surge watches and warnings across the Caribbean and Pacific, said Cody Fritz, the center's storm surge unit lead. They're rolling out the first storm surge watches and warnings, and peak surge forecasts for Hawaii this year.
People tend to "focus so much on the center of the track that they're not really acknowledging the hazards that are associated outside the track, in some cases hundreds of miles outside that track," he said.
The cone is like a Table of Contents, Berg said. "That's all it is. You don't get a full story just reading the table of contents. You have to actually look at other products to understand more about the risk."
Dinah Voyles Pulver, a national correspondent for USA TODAY, writes about violent weather, climate change and other news. Reach her at dpulver@usatoday.com or @dinahvp on Bluesky or X or dinahvp.77 on Signal.
This article originally appeared on USA TODAY:Famous National Hurricane Center forecast track map gets a makeover
