Humberto became the first hurricane of the season, forming in the east of the Atlantic 310 miles west-northwest of the Cape Verde islands, according to the U.S. National Hurricane Center.
Humberto was announced in a 5 a.m. eastern time advisory, missing the record for the latest hurricane debut since satellites have been able to watch the whole Atlantic by three hours, according to Dennis Feltgen, a spokesman for the Miami-based center. The all-time record is Oct. 8, 1905, he said.
The storm had maximum sustained winds of 75 miles per hour (120 kph) and is moving north-northwest at 8 mph, the hurricane center said. No coastal watches or warnings were in effect.
Tropical storm Gabrielle weakened while moving away from Bermuda, the hurricane center said. Maximum sustained winds were 50 mph, down from 60 mph in a 2 a.m. advisory, with additional weakening predicted over the next 48 hours.
Eight tropical storms have formed in the Atlantic so far this season, which began June 1 and runs through Nov. 30. The systems are followed closely by energy and commodity markets because they can disrupt supply and demand of petroleum products, natural gas and crops.
The Gulf of Mexico is home to about 6 percent of U.S. natural gas output, 23 percent of oil production and more than 45 percent of petroleum refining capacity, according to the U.S. Energy Department.
Florida, which is struck more often than any U.S. state, is the second-largest producer of oranges after Brazil.