Tropical Storm Sam formed Thursday in the Atlantic Ocean – the 18th named system in a bustling season – and is expected to intensify into a hurricane by this weekend.
The storm’s maximum sustained winds were near 50 mph with additional strengthening expected, the National Hurricane Center said. The storm was centered about 1,745 miles east-southeast of the northern Leeward Islands and was moving west about 16 mph on Thursday.
Sam could whip up into a major hurricane before approaching the islands of the northern Caribbean next week, Accuweather said.
“Intensification is expected through the rest of this week and into the weekend, and Sam is expected to become a hurricane late Friday or Friday night,” AccuWeather Senior Meteorologist Rob Miller said.
Tropical storms become hurricanes when maximum sustained winds hit at least 74 mph.
The storm was expected to take a west to west-northwest track across the central Atlantic over the weekend, Accuweather said. Whether it makes landfall is still uncertain, but forecasters urged Bermuda, the Bahamas and the U.S. East Coast to stay vigilant.
“Sam could approach the northern Leeward Islands by Tuesday of next week as a major hurricane,” Miller said, noting the storm’s maximum sustained winds could be at least 111 mph, the threshold for a Category 3 hurricane.
Most computer model forecasts show Sam swirling away from the East Coast late next week, weather.com said, because of a Bermuda high over the Atlantic and a southward plunge of the jet stream that could drive Sam north and northeast instead of westward toward the U.S.
Sam could also mimic Hurricane Larry earlier this month and kick up dangerous surf and rip currents along the Eastern Seaboard, forecasters said.
Two other systems, tropical depressions Peter and Rose, have both fallen apart. But Odette, a storm that first formed off the East Coast last week, could regain tropical storm status over the open waters of the north Atlantic, Accuweather said.
Sam is the 13th named storm to form in the Atlantic since Aug. 11, according to Colorado State University hurricane researcher Phil Klotzbach. And only one other hurricane season on record has had 18 named storms by Sept. 23, he said: 2020 had 23 named storms by that date.
So far this year there have been six hurricanes and three major hurricanes (Category 3 or stronger): Grace, Ida and Larry.
In August, the National Oceanic and Atmospheric Administration released its updated hurricane season forecast for the year: seven to 10 hurricanes; 15 to 21 named storms.