Hurricane Dorian made landfall on the eastern end of Grand Bahama Island, the National Weather Service said Sunday night.
Grand Bahama Island is a little more than 50 miles east of West Palm Beach, Florida. The island's eastern end is less heavily populated than its western side, which includes the city of Freeport.
"Dorian will continue to slow as it moves westward across the Northwestern Bahamas overnight before a gradual turn to the northwest then north through Wednesday," the NWS said on its website.
"Given uncertainty in the track forecast and the anticipated increase in size of the hurricane, a Hurricane Warning and Storm Surge Warning have been issued for a portion of the Florida east coast," it said.
The "extremely dangerous" storm is the strongest hurricane on record in the Northwestern Bahamas, with maximum sustained winds at 185 mph and gusts over 220 mph.
The National Hurricane Center said "catastrophic hurricane conditions" are occurring in the Abacos Islands and are expected to spread across Grand Bahama Island later Sunday. Hurricane conditions are possible in parts of Florida by late Monday or early Tuesday.
"Maximum sustained winds have increased to near 180 mph (285 km/h) with higher gusts," the agency said in an update posted Sunday morning. "Dorian is a extremely dangerous category 5 hurricane on the Saffir-Simpson Hurricane Wind Scale."
The Saffir-Simpson scale is the classification system for Western Hemisphere tropical cyclones. A category 5 rating means the storm has reached reached wind speeds of at least 136 knots or 157 miles per hour. Dorian is the 35th category 5 storm ever recorded in the Atlantic Ocean.
While the storm's intensity is likely to fluctuate Dorian is expected to remain a powerful hurricane during the next few days, the agency said.
Millions of residents along the Southeastern U.S. coast are on high alert amid warnings the storm would move northeast after battering the Bahamas, threatening Florida, Georgia and the Carolinas.
The NHC also issued a tropical storm warning for parts of Eastern Florida — north of the state's Deerfield Beach to Sebastian Inlet — meaning tropical storm conditions are expected in the area generally within 36 hours.
"Interests elsewhere in southern and central Florida should continue to monitor the progress of Dorian. Additional watches or warnings may be required for portions of the east coast of Florida today," the center's statement said.
Historically, early September has seen the most category 5 hurricanes and is considered the peak of the Atlantic hurricane season.
NBC News, in a tweet, showed a video of Hurricane Dorian pounding northern Bahamas.