The NHC said in its latest advisory that as of 8 p.m. on Saturday, Dorian was still moving west at just 12 kph.
The advisory said that the storm has remained a Category 4 with maximum sustained winds of 241 kph, which is just 11 kph away of Category 5.
A hurricane warning was in effect for the northwestern Bahamas, with the Abaco Islands and Grand Bahama Island likely to bear the brunt of the storm, Efe news reported.
After making landfall in the Bahamas, Dorian will then head close to Florida's eastern coast beginning late Monday.
Whether it makes landfall in Florida is increasingly uncertain. Some forecast models late Saturday showed the hurricane veering north and skirting the coast as it heads toward Georgia and the Carolinas by the middle of next week, causing flooding and strong winds.
The NHC stressed that Dorian could still wreak havoc in coastal Florida and that large portions of the coast remain imperiled.
Ken Graham, Director of the NHC, said the latest models show Dorian far less likely to make landfall in Florida than earlier expected.
He said that there was still significant uncertainty in the forecast for Dorian, adding "we're going to be dealing with this for a while".
Florida Governor Ron DeSantis urged residents to remain vigilant and to heed local officials' warnings.
"Even if it doesn't directly strike Florida, this is a big, powerful storm," he said on Saturday. "You're still looking at significant impacts even if the storm remains hugging the coast."
Forecasters said tropical-storm conditions, with sustained winds of 62 to 117 kph, were possible in the state by late Monday.
In South Carolina, Governor Henry McMaster declared a state of emergency on Saturday. "Given the strength and unpredictability of the storm, we must prepare for every possible scenario," he said.
Governor Brian Kemp of Georgia has also declared a state of emergency in 12 counties in the southern coastal area of the state.
Four other weather systems have intensified to at least tropical storm strength during the 2019 Atlantic hurricane season, which began in June and technically ends on November 30.
One of them, Barry, became a Category 1 hurricane shortly before making landfall on July 13 in Louisiana, where it caused as much as $900 million in property damage but no fatalities.
( With inputs from IANS )