What the NHC Hurricane Cone Shows, and What It Leaves Out

The National Hurricane Center cone shows only the probable track of the center of a tropical cyclone, not the size of the storm or where its damage will reach (NHC, Definition of the Track Forecast Cone).

NHC builds the cone by enclosing the area swept out by a set of circles placed along the forecast track at 12, 24, 36, 48, 60, 72, 96 and 120 hours. The circles themselves are not drawn on the Florida map; only the outline they sweep out is (NHC cone definition).

Each circle is sized so that two-thirds of historical official forecast errors over a 5-year sample fall inside it. The one-third of past NHC errors that land beyond each circle is part of the design, which is why NHC presents the cone as a probable track and not a boundary (NHC cone definition).

The same graphic carries the NHC track forecast as dots at the times indicated, and the letter in each dot gives the forecast strength category, with S for storm, H for hurricane and M for major hurricane. A post-tropical system forecast to have 75 mph winds is drawn as a black H in a white dot, even though it is not a hurricane (NHC graphical product descriptions).

For the 2026 hurricane season the Atlantic cone circles grow from 25 nautical miles at 12 hours to 200 nautical miles at 120 hours, based on NHC error statistics from 2021 to 2025 (NHC cone definition, 2026 radii).

Source for every row: NHC, Definition of the NHC Track Forecast Cone, which states that the radii come from error statistics for 2021 to 2025.

At 120 hours the NHC table gives 200 nautical miles for the Atlantic basin and 138 nautical miles for the Eastern and Central North Pacific. NHC labels the table as the radii for 2026, drawn from the 2021 to 2025 error statistics (NHC cone definition).

The radius figures are nautical miles, not statute miles. NHC states that the size of each circle is set so that two-thirds of historical official forecast errors over a 5-year sample fall within it, and separately cautions that hurricane and tropical storm force winds can extend well beyond the cone (NHC graphical product descriptions).

The cone marks the probable track of the center, and NHC states that tropical cyclones are not a point and that their effects can span many hundreds of miles from the center (NHC graphical product descriptions).

NHC says the area with hurricane-force winds, a one-minute average of at least 74 mph, and tropical-storm-force winds, a one-minute average of 39 to 73 mph, can extend well beyond the white area that marks the most likely track of the center. The wind field drawn on the cone graphic is itself a maximum: the wind radii show the greatest possible extent of a given wind speed in each quadrant, so not every Florida location inside the orange or red shading will see those winds (NHC graphical product descriptions).

The NHC hazards page lists storm surge and storm tide, heavy rainfall and inland flooding, high winds, rip currents and tornadoes as the major hurricane hazards. It says storm surge and large waves pose the greatest threat to life and property along the coast, that surge can travel several miles inland, and that flooding is the major threat for people living inland. It adds that rainfall amounts are not directly related to a storm's strength but to its speed and size and the local geography, with slower and larger storms producing more rain (NHC, Hurricane Preparedness: Hazards).

Wind damage can also run far inland in Florida. NHC uses Hurricane Charley in 2004 as its example: the storm made landfall at Punta Gorda on the southwest Florida coast and produced major damage well inland across central Florida, with gusts of more than 100 mph. The same NHC page notes that tornadoes from tropical cyclones most often form in rain bands well away from the center (NHC hazards page).

Alongside the cone, which covers the probable track of the center, NHC publishes separate wind probability, wind arrival time, Key Messages and storm surge graphics (NHC graphical product descriptions).

The wind speed probability graphics give the chance that sustained winds of 34 knots (tropical storm force), 50 knots or 64 knots (hurricane force) will occur at a location over cumulative periods out to 120 hours. They are based on NHC track, intensity and size forecasts and their historical errors, and NHC warns that probabilities that look small, such as 5 to 10 percent, may still be quite significant (NHC wind speed probabilities description).

NHC says emergency managers plan to finish evacuations and shelter their staff before tropical-storm-force winds arrive, not hurricane-force winds (NHC hazards page). The Earliest Reasonable Arrival Time marks the time before which there is no more than a 10 percent chance that sustained tropical-storm-force winds begin, the window in which preparations should ideally be finished by anyone with a low tolerance for risk. The Most Likely Arrival Time marks the point before or after which onset is equally likely (NHC arrival time description).

Key Messages, when NHC issues them, appear in the Tropical Cyclone Discussion and highlight hazards and forecast uncertainty for select storms. The Key Messages graphic can include the cone, the 34-knot cumulative wind probability graphic, the arrival time graphic, the peak storm surge graphic or a Weather Prediction Center rainfall forecast, and NHC encourages sharing it (NHC Key Messages description).

NHC normally issues Atlantic cone graphics every six hours, at 5:00 AM, 11:00 AM, 5:00 PM and 11:00 PM EDT, with updates for intermediate advisories and special graphics at any time (NHC graphical product descriptions).

When coastal watches or warnings are in effect, NHC issues intermediate public advisories every 3 hours, and United States watches or warnings can be issued with regular or intermediate advisories. The Public Advisory is the NHC product written for a general audience, while the Forecast/Advisory carries the track, intensity and size forecast for 12, 24, 36, 48, 60, 72, 96 and 120 hours (NHC text product descriptions).

Source for every row: NHC Glossary. The glossary explains the lead times by noting that hurricane preparedness becomes difficult once winds reach tropical storm force, which is why the hurricane watch and hurricane warning lead times are counted to the onset of tropical-storm-force winds.

During the 2026 hurricane season NHC is issuing an experimental cone built from ellipses instead of circles, alongside the operational cone, not in place of it (NHC Experimental Tropical Cyclone Forecast Cone Graphic).

NHC explains that the operational cone has been built since 2007 from circles based on the 67th percentile of NHC absolute track errors over the previous five years. The experimental version anchors an ellipse at each forecast point from 12 to 120 hours, with axes based on the 90th percentile of along-track (speed) and cross-track (direction) errors from the previous five years. Because the storm center would be expected to stay within each ellipse 90 percent of the time, NHC describes the experimental cone as the likely track area of the center (NHC experimental cone page).

Along-track error measures how far the storm center ends up ahead of or behind the NHC forecast, and cross-track error measures how far it drifts left or right of the forecast line. The experimental cone appears on hurricanes.gov with each advisory or special advisory, and the National Weather Service is taking comments on it through November 30, 2026, the same date the NHC glossary gives as the end of the Atlantic hurricane season, which runs from June 1 to November 30 (NHC experimental cone page; season dates from the NHC Glossary).

Last verified: October 18, 2026, by re-reading the NHC cone definition and its 2026 radius table, the experimental cone notice, the NHC graphic and text product guides, the NHC glossary and the NHC hazards page.