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.

But on its current path Sam is not expected to hit the Virgin Islands.

The storm had maximum sustained winds of about 60 mph as of 5 p.m. EDT with additional strengthening expected, the National Hurricane Center said. The storm was centered about 1,635 miles east-southeast of the northern Leeward Islands and was moving west about 16 mph.

Sam could whip up into a major hurricane before approaching the islands of the northern Caribbean next week: “Sam is forecast to become a hurricane tomorrow morning and could become a major hurricane by Saturday,” the Hurricane Center 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

Most computer model forecasts show Sam swirling away from the East Coast late next week, 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 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.

Meanwhile, a tropical wave is expected to roll off Africa’s west coast by end of the weekend. It’s forecast to move west at 10 to 15 mph and, as of Thursday, odds of its development were low, according to the hurricane center.

Forecasters say the hurricane season will remain busy for the next few weeks.

“There’s definitely precedent, and unfortunately it seems like last year is a relatively close match for this year in terms of how things have evolved,” he said in reference to the record 30 named storms of the 2020 hurricane season.

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.