The National Hurricane Center in Miami stressed that Dorian could still hit Florida, where millions of people have been in the storm's changing potential path.
A hurricane warning is in effect in the northwestern Bahamas, excluding Andros Island, where a hurricane watch is in effect. Powerful winds will lash the Florida coast as early as Sunday night and could blow fiercely up the east-coast of the state well into Wednesday morning.
"The best estimate of the initial motion is toward the west or 280 degrees at 8 kt".
"That will enable us to draw down more federal resources in anticipation of this storm", the governor said.
Over two or three days, the hurricane could dump as much as one metre of rain, unleash devastating winds and whip up an abnormal and risky rise in sea level called storm surge, according to private meteorologist Ryan Maue and some of the most reliable computer models.
The latest projection by the National Oceanic and Atmospheric Administration foresees the storm battering eastern Florida before moving northward toward the Carolinas. Dorian is expected to be near or over the island chain on Sunday.
The Miami-based National Hurricane Centre said in a statement that Dorian had strengthened into an "extremely dangerous" category four hurricane, packing maximum sustained winds of 215 kilometres per hour.
The storm still holds the record for the lowest barometric pressure to hit the USA from the Atlantic Ocean. Matthew approached Florida and headed north, staying just offshore before moving along South Carolina's coast without making a major landfall. Dorian is now a category 5 hurricane on the Saffir-Simpson Hurricane Wind Scale.
Dorian by late Monday is due to get closer to the Florida's east coast, the hurricane center said.
Sitting approximately 415 miles from West Palm Beach, Fla., as of 11 a.m. Saturday morning, Hurricane Dorian's anticipated course recently shifted to put North Carolina in the potential path.
NASA watches Hurricane Dorian flex its muscles
Several hundred customers were without power across Puerto Rico, said Ángel Figueroa, president of a utility workers union. Virgin Islands, ordering federal assistance with disaster relief for the U.S. territory.
Hurricane Dorian is now sustaining maximum wind speeds of 150mph. Forecasters warned that its slow movement means Florida could face a prolonged wallop of wind, storm surge and torrential rain.
Meteorologists said Dorian has grown into an extremely unsafe Category 4 storm as it heads toward land.
As Dorian closed in, Labour Day weekend plans were upended.
Hurricane Dorian's wind speeds are just 7mph away from being classed as a Category 5 hurricane. The hurricane continues to move west at 8 miles per hour (13 kph), with maximum sustained winds of 150 miles per hour (240 kph).
The storm will be near or over the northwestern part of the Bahamas.
Millions of US coastal dwellers from Florida to the Carolinas are keeping a wary eye on Dorian's approach.
Also, previous forecasts showed Dorian hitting Florida on early Tuesday, Sept. 3.
A unsafe Hurricane Dorian is closing in on the northern Bahamas, threatening to batter the normally idyllic islands with fierce winds, pounding waves and torrential rain. "We encourage all South Carolinians who may be impacted by Hurricane Dorian to be vigilant and prepare now - there is no reason for delay".
Jeffrey Allen, who lives in Freeport on Grand Bahama, said he had learned after several storms that sometimes predictions of damage don't materialize, but he still takes precautions.