The US National Hurricane Center says the government of Antigua and Barbuda has discontinued the Tropical Storm Warning for Montserrat.
The NHC in its 5 pm update said Ernesto is heading toward the Virgin Islands and is expected to become a hurricane tonight while passing northeast of Puerto Rico.
On the forecast track, the centre of Ernesto should pass near or over the Virgin Islands this evening, and then pass just to the northeast and north of Puerto Rico tonight and on Wednesday.
Ernesto should then move over the western Atlantic later in the week and be near Bermuda by Friday.
Data from an Air Force Reserve Hurricane Hunter aircraft indicate that maximum sustained winds are near 60 mph (95 km/h) with higher gusts.
Strengthening is forecast, and Ernesto is expected to become a hurricane by tonight to the north of the Virgin Islands and Puerto Rico.