A tropical storm warning is in effect for Bermuda as Tropical Storm Sean continues to swirl in the Atlantic, off the British territory.

The National Hurricane Center in Miami said in its latest bulletin Thursday that Sean was about 465 kilometers west-southwest of Bermuda, moving toward the northeast with 100 kilometer-per-hour winds. The weather system is expected to pick up speed before it begins to weaken slowly.

Weather forecasters warned that storm conditions on Bermuda were expected to begin late Thursday, predicting that Sean would produce up to 8 centimeters of rain. Swells generated by the storm are affecting parts of the southeastern United States and Bermuda, with life-threatening surf and rip currents.

The Atlantic hurricane season began June 1 and ends November 30.