MIAMI — Hurricane Gabrielle churned Tuesday afternoon across open Atlantic waters ever closer to the Azores as forecasters warned residents of the volcanic archipelago to be on guard for a possible strike.

In the Pacific, Narda was upgraded to a hurricane off the west coast of Mexico after steady strengthening while moving away from land, the U.S. National Hurricane Center said.

In the North Atlantic, a hurricane watch was issued for all of the Azores chain ahead of Gabrielle. Currently a dangerous Category 4 hurricane, Gabrielle was centered about 1,635 miles west of the island chain by Tuesday afternoon and was expected to still be a hurricane upon its approach there Thursday.

Forecasters at the Miami-based hurricane center said Gabrielle was expected to cross over the island chain late Thursday night and early Friday, warning that a dangerous storm surge and significant coastal flooding could be expected in areas near a possible landfall.

Gabrielle had maximum sustained winds Tuesday of 130 mph as a major hurricane and was traveling to the east-northeast at 21 mph with some forward acceleration expected in the coming days.

Forecasters predict Gabrielle will bring up to 5 inches of rain across the central and western Azores. The weather center also warned the storm could churn up large and destructive waves near coastlines.

The storm has powered up large ocean swells on Bermuda’s beaches after passing by that territory on Monday. The swells were also expected to continuing impacting the U.S. East Coast from North Carolina to Atlantic Canada.