Hurricane Lee weakened slightly into a Category 4 storm Friday morning, following a day in which the hurricane strengthened at a historic pace into a powerful Category 5 rarely seen in the Atlantic Ocean.

The hurricane is packing destructive maximum sustained winds of 155 mph and is about 550 miles east of the northern Leeward Islands.

“Although Lee’s current intensity is lower than the overnight peak, the hurricane remains very powerful,” the National Hurricane Center said, noting that more slight fluctuations in maximum winds are expected over the next several days.

Lee is expected to remain a major hurricane over the southwestern Atlantic early next week, though it’s too soon to know whether this system will directly impact the US mainland.

Lee, which was a Category 1 storm Thursday, intensified with exceptional speed in warm ocean waters, doubling its wind speeds in just a day.CNN