MIAMI — We are a little over two months until the start of the 2025 Atlantic Hurricane Center, and the National Hurricane Center (NHC) has some new changes this year.
1. Experimental cone changes
In 2024, the NHC issued an "experimental cone" with inland watches and warnings. Based on feedback, they will debut diagonal pink and blue lines over areas that have both a tropical storm warning and a hurricane watch in effect. The goal of these changes is to communicate wind risk while not overcomplicating with too many layers.
2. Rip current risk map
According to the NHC, during the past decade, there has been an increase in rip current fatalities in the United States, many of which occur from swells of distant hurricanes. They will now issue a national rip current risk map for the current day, the next day and the greatest risk areas when we have a tropical system — even if it is expected to be a "fish storm" — and rip current conditions along the U.S. coastline.
3. Potential tropical cyclone lead times
A Potential Tropical Cyclone (PTC) is a disturbance that is not yet a tropical cyclone but poses the threat of bringing tropical storm or hurricane conditions to land. The NHC will now be able to issue advisories for potential tropical cyclones up to 72 hours (three days) in advance instead of 48 hours. This gives longer lead times when confidence is high that there is a significant risk of wind and storm surge impacts to land areas.
4. Hurricane-force wind fields
Previously, the NHC has issued 48-hour forecasts for sustained hurricane-force wind fields using the maximum extent of wind radii in nautical miles. One of their new changes will extend the forecast to 72 hours out. They will also use meters instead of feet in their high seas product for the maximum extent of seas in each quadrant surrounding the center of the tropical cyclone.
5. Smaller forecast cone
One of the most interesting changes will be to the forecast cone. The size of the tropical cyclone track forecast error cone for the Atlantic basin in 2025 will be about 3–5% smaller as compared to 2024.
The cone represents the probable track of the center of a tropical system and is made by a set of imaginary circles placed along the forecast track (at 12, 24, 36 hours, etc.). The size of each circle is set so that 2/3 of historical official forecast distance errors, over the previous five years, fall within the circle.
Other adjustments made for the upcoming season include probabilistic storm surge forecasts for the Hawaiian Islands.
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