Two people watch in 2015 as a large wave bears down on the rocky shore along Ocean Drive in Acadia National Park. An ocean gale that blew past Maine Wednesday night and Thursday pelted the coast and nearby areas with heavy rains and high winds. Credit: Bill Trotter | BDN

As rain falls across much of Maine Saturday morning, the biggest effects of Hurricane Dorian will be felt along the coast during the afternoon and evening hours when winds and waves are expected to pick up.

The National Weather Service has issued a tropical storm warning for coastal Hancock County and Washington County, where the most extreme impacts from Dorian will be felt in terms of high winds and surf.

Maine’s entire coastline will remain under a high surf advisory until early Sunday morning.

Caribou-based National Weather Service Forecaster Donald Dumont said Saturday morning that wave heights were just beginning to “increase sharply” near outer wave detection buoys in the Gulf of Maine. The strongest winds and waves are expected to hit the coast around mid-afternoon and linger into the evening hours.

Waves with heights of 8 to 10 feet are being predicted in the Hancock and Washington County area, along with localized wind gusts with speeds up to 45 miles per hour. Wind gusts could reach up to 50 miles per hour in the extreme Downeast region.

Dorian’s impact on the Maine coast is on the weaker side of a tropical storm warning, Dumont said. But he still advised people to use caution near the coastline.

“Don’t get too close to the coast,” Dumont said. “Whatever you think is a safe distance, it probably isn’t.”

[ Dorian could kick up a dangerously high surf along Maine’s coast this weekend]

Acadia National Park rangers have closed access to Thunder Hole and Sand Beach due to the anticipated storm surge. According to the park’s website, additional closures may be made along Ocean Drive and Schoodic Point.

In 2009, a large wave produced by Hurricane Bill swept several visitors to Acadia National Park into the sea near Thunder Hole and carried three of them out toward open water. One of the three, a young girl from New York City, drowned before she could be rescued by responding Coast Guard personnel.

Ten years before that, a married couple from Charleston was pulled into the sea and drowned by a large wave at Schoodic Point.

Behind the high waves expected to hit the coast this afternoon are long swells, Dumont said, which carry with them a lot of strength.

“There’s going to be a lot of energy behind the waves, so it can be a dangerous situation,” Dumont said.

Waves will peak around high tide this evening, Dumont said, which will occur between 6 and 7 p.m. along Maine’s coastline.

By Sunday morning, Dorian will have moved out of the Gulf of Maine, giving way to what Dumont called a “nice, cool fall-like day.”

Earlier this week, Dorian was a Category 5 storm on the Saffir-Simpson Scale, with sustained wind speeds of more than 180 mph and gusts exceeding 220 mph, when it struck Great Abaco Island in the Bahamas on Sunday. At least 30 people in the Bahamas were killed by the storm, the Associated Press has reported.

This story will be updated.

Bill Trotter contributed to the reporting in this story.