Miami ? A tropical depression formed late Sunday in the southeast Caribbean Sea and was expected to strengthen into Tropical Storm Gamma today, the National Hurricane Center said.

The storm was expected to be south of Jamaica by the end of the week, over Caribbean waters still warm enough to feed a major hurricane, said hurricane specialist Stacy Stewart.

It is not expected to threaten the United States.

At 9 p.m. CST Sunday, the depression was about 115 miles west of St. Lucia and about 100 miles west of St. Vincent. Its maximum sustained winds were near 35 mph, and it was moving west-northwest near 10 mph.

If the system becomes a tropical storm – which will happen if its maximum sustained winds reach 39 mph – it would become the 24th named storm of the Atlantic hurricane season, extending this year’s record. The previous record of 21 named storms had stood since 1933.