Introduction to Cone-of-Uncertainty Maps
The “cone of uncertainty” map that the National Hurricane Center uses to communicate risk as storms form is getting some updates this year. The cone, which shows the probable path of the storm’s center in the coming five days, will be 3% to 5% narrower this year than last, and significantly narrower than it was 20 years ago.
Understanding the Cone of Uncertainty
The narrowing of the cone does not mean storms have a smaller circumference, it means forecasts are becoming more accurate — there’s less path uncertainty, and thus less cone. “Overall, hurricane track forecasts are gradually improving, meaning that in general, there is less uncertainty where a storm will track now than there was a couple decades ago,” wrote Brian McNoldy, hurricane expert at the University of Miami’s Rosenstiel School of Marine, Atmospheric, and Earth Science in a recent blog post. “It’s getting increasingly hard to make it smaller,” he said in a follow-up phone conversation.
Factors Influencing the Cone’s Size
A faster-moving storm will have a longer cone, but the width of the cone five days out will be the same for every storm this year. Beyond five days, the cone can become quite wide. Last year, the NHC started issuing an experimental cone map that included inland hazards, such as hurricane warnings well up into Georgia for Hurricane Helene. Helene sent up to 30 inches of rain into North Carolina, causing death and mass flood destruction.
Experimental Cone Maps
The NHC will again issue an experimental version of the cone graphic that includes a depiction of inland tropical storm and hurricane watches and warnings in effect for the continental United States. The official operational cone will still show only coastal watches and warnings. “I think (the experimental graphic) is a huge improvement,” said McNoldy. “I’m happy to hear it’s going to be continued.” The experimental graphic will come out about 30 minutes after the operational map, which comes out with each advisory.
Additional Improvements
Other improvements allowed the NHC to offer advisories on Potential Tropical Cyclones — storms that are not officially tropical cyclones, but still dangerous, with tropical storm or hurricane conditions. Previously, these advisories were given two days in advance of anticipated arrival of storm surge or tropical-storm-force winds. Now the NHC will be able to give them three days in advance. The NHC also will issue forecasts for sustained hurricane-force wind radii three days out, instead of two days.
Interpreting the Cone of Uncertainty
McNoldy said to remember that the cone is not a cone of risk, it’s a cone predicting the path of the center of the storm. There is a 1/3 chance the storm will track outside the circle, and it could track to the top or bottom as well. That translates to risk well outside the cone. Storm surge and other dangerous forces — such as the dozens of tornadoes that ripped through southeast Florida when Milton made landfall on the west coast — can inflict damage hundreds of miles away. Additionally, the cone does not depict the size of the storm.
Naming Storms
Here’s the list of 2025 Atlantic Basin tropical storm and hurricane names:
— Andrea
— Barry
— Chantal
— Dexter
— Erin
— Fernand
— Gabrielle
— Humberto
— Imelda
— Jerry
— Karen
— Lorenzo
— Melissa
— Nestor
— Olga
— Pablo
— Rebekah
— Sebastien
— Tanya
— Van
— Wendy
Conclusion
The updates to the cone of uncertainty map are a significant improvement in hurricane forecasting, allowing for more accurate predictions and better preparation for potential storms. While the cone is not a guarantee of the storm’s path, it provides valuable information for those in the potential impact zone. By understanding the limitations and capabilities of the cone, individuals can make informed decisions to ensure their safety.
FAQs
Q: What does the cone of uncertainty represent?
A: The cone of uncertainty represents the probable path of the storm’s center in the coming five days.
Q: Why is the cone narrower this year?
A: The cone is narrower this year because forecasts are becoming more accurate, resulting in less path uncertainty.
Q: What is the experimental cone map?
A: The experimental cone map includes inland hazards, such as hurricane warnings well up into Georgia, and will be issued about 30 minutes after the operational map.
Q: How often will the NHC issue advisories on Potential Tropical Cyclones?
A: The NHC will issue advisories on Potential Tropical Cyclones three days in advance of anticipated arrival of storm surge or tropical-storm-force winds.
Q: What is the list of 2025 Atlantic Basin tropical storm and hurricane names?
A: The list includes names such as Andrea, Barry, Chantal, and more, and can be found in the article above.
