National Hurricane Center Shrinks “Cone of Uncertainty”

MIAMI, Florida – The National Hurricane Center is making its “Cone of Uncertainty” smaller for the Atlantic Hurricane basin starting with the 2018 Atlantic Hurricane Season.

The cone, which has become well-known to Floridians after Hurricanes Irma and Matthew, represents the probable track of the center of a tropical cyclone, and is formed by enclosing the area swept out 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 two-thirds of historical official forecast errors over the previous five years (2013–2017) fall within the circle.

As pictured above, the cone uncertainty encompassed the entire Florida peninsula as Category 5 Hurricane Irma approached the Sunshine State.

The smaller cone is among a long list of tweaks that the agency made to its weather forecast products and models. The NHC will also extend its advisories and watches and warnings from 48 hours to 72 hours.