Where and When the Season's First Atlantic Hurricane Forms

We've taken a look at where and when the first hurricane of each Atlantic hurricane season developed from 1950-2018, based on data from the National Hurricane Center (NHC), and noticed a couple of trends. Many first hurricanes in the Atlantic form close to the U.S., impact land and develop in mid-to-late August.

The map below shows where each storm was first designated a hurricane by the NHC.

There are a few clusters, including one in the main development region (MDR), off the west coast of Africa into part of the Caribbean. Activity here is usually greatest from August into September. Hurricane Beryl was the first hurricane of the season when it formed in early July 2018 and it formed in this region, although a bit farther south than most Atlantic hurricanes.

Two other areas common for development early in the season are closer to the U.S. – in the western Gulf of Mexico and off the Southeast coast. This includes Hurricane Franklin in August 2017 which became a hurricane in the Bay of Campeche before making landfall in Mexico.

In June, some of the activity in the Gulf of Mexico and off the Southeast coast comes from decaying cold fronts. In July, cold fronts become much less frequent but thunderstorm complexes rolling off the Southeast coast can linger and lead to tropical cyclone formation.

As hurricane season progresses, tropical waves start coming off the coast of Africa.

Interestingly, a majority of the first hurricanes of the season impacted land, partially due to close formation to land. In 1966, Hurricane Alma became the earliest hurricane to strike the continental U.S. since 1825 when it made landfall in Florida on June 9 as the equivalent of a Category 2 hurricane on the Saffir-Simpson Hurricane Wind Scale.

Another interesting first hurricane is Agnes (1972), which made landfall in Florida and again in New York and caused extensive flooding, 100 deaths and more than $2 billion in damage.

Hurricane Allen in 1980 was a classic Cape Verde hurricane and reached Category 5 strength, but it weakened some before making landfall near the Texas-Mexico border.

As the graph above shows, the most common time period for hurricane development is Aug. 16-31, followed by Aug. 1-15. This is not that surprising given that tropical activity typically heats up in the second half of August.

The Atlantic hurricane season officially last June 1-Nov. 30, but tropical cyclones do occur outside of these months. Three of the first hurricanes of the season formed before June 1, including Hurricane Alex in 2016, which formed south of the central Azores; Hurricane Alma in 1970, which developed north of Panama; and, Hurricane Able in 1951, which strengthened into a hurricane off the coast of Florida.

The latest first hurricane of the season from 1950 to 2018 did not occur until Sept. 11 in 2013 (Humberto) and in 2002 (Gustav).