New Hurricane Cone Aims for Clearer Storm Risk

The National Hurricane Center is introducing significant upgrades to its hurricane forecast cone graphic, set to debut when the first tropical storm forms this summer. This evolution aims to enhance public and emergency manager understanding of storm hazards and risks. The widely used five-day track graphic, which has been in place since 2002, is being revised because it often failed to convey the full range of impacts, such as high winds and heavy rainfall extending inland.

The updated graphic will now clearly depict inland tropical storm and hurricane watches and warnings across the continental United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands. This expansion is designed to better illustrate wind risks and hazards that can extend beyond the traditional cone. Following a two-year experimental phase for public feedback, adjustments have been made to the legend and color schemes to improve clarity.

Furthermore, an experimental version of the cone graphic will be available, employing ellipses instead of concentric circles. This change is based on research indicating ellipses are more effective at illustrating forecast errors both along and across the storm's track. This new graphic will be based on a 90% probability, offering higher confidence that the storm's center will remain within the forecast area, addressing a key limitation of the previous 67% probability model.