Hurricane Sam strengthens to a category 4 storm

Hurricane Sam rapidly strengthened into a Category 4 storm overnight with maximum sustained winds of 140 mph (220 km/h).

The United States National Hurricane Center (NHC) said Sam was expected to strengthen further overnight.

Timelapse imagery captured by the National Oceanic and Atmospheric Administration’s GOES-East satellite shows the hurricane’s progression over a three-hour period on Saturday while it was classified as a Category 3 storm.

The storm poses no threat to land as it moves northward several hundred miles east of the southern Caribbean, moving through the Atlantic Ocean.

Forecasters said swells generated by the hurricane could reach the Lesser Antilles early this week.