This image provided by NASA shows a natural-color image of Hurricane Danielle taken at 12:50 p.m. ET on Thursday. (NASA/Associated Press)

Hurricane Danielle, the fourth named storm of the Atlantic hurricane season, has reached major hurricane status, forecasters say.

The hurricane, which has maximum sustained winds of 215 kilometres per hour, was bumped to a Category 4 storm early Friday, forecasters at the U.S. National Hurricane Center said.

The storm was about 875 kilometres southeast of Bermuda Friday morning, forecasters said.

"This is the strongest hurricane so far this season, but it's still not expected to make landfall," CBC meteorologist Johanna Wagstaffe said.

Forecasters said swells churned up by Danielle could reach parts of the U.S. East Coast by the weekend and that dangerous surf conditions are expected in Bermuda, though the eye will likely move well east of the island.

The storm could strengthen over the next 24 hours, forecasters said.

With files from The Associated Press