Getaway Friday is shaping up to be the best day of the extended Labor Day weekend on Long Island, forecasters said.

Thanks to Tropical Storm Hermine, expected to be sitting off the mid-Atlantic, some rain, coastal flooding and high winds could strike Long Island over the weekend, the National Weather Service said.

But Friday’s outlook appears good for outdoor activities, with mostly sunshine, daily highs in the low 80s and a north wind from 8 to 11 mph.

What had looked to be a sunny Labor Day weekend locally changed with Wednesday’s forecast, when the potential for rain dampened the unofficial close to summer.

The weather service forecast says the chance for rain Saturday and Sunday ranges from 30 percent to 40 percent.

News 12 Long Island meteorologist Matt Hammer said the exact track and strength of Hermine remains in question.

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“But we’re still thinking coastal flooding will be the main problem, followed by wind then rain,” Hammer said.

Hammer said Friday is “definitely the best day of at least the next four days.”

Last year for the Labor Day weekend, AAA predicted 35 million travelers, but this year it discontinued its annual survey for Labor Day as a cost-saving measure, spokesman Robert Sinclair said.

Nonetheless, the ingredients had been there — until the forecast changed — for a busy travel weekend through the end of the day Monday, the holiday.

Gasoline prices on Long Island are averaging $2.35 a gallon, the lowest prices since 2004, when a gallon averaged $2.05, the auto club said.

Americans are driving more, 282 billion miles in June, 8 billion more than the previous June, according to the most recent federal estimates.

The Long Island Rail Road said it will put on extra trains Friday for the getaway, then run a holiday schedule for the three-day weekend.

The LIRR will operate 10 extra eastbound trains Friday from Penn Station between 1:49 p.m. and 3:48 p.m. for customers looking for an early getaway for Labor Day weekend.

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Most nonemergency road construction projects in the region will be halted for the weekend.

Motorists heading to New York City are being advised that the West Indian American Day Parade, and the J’Ouvert Festival that precedes it, will result in street closings in Brooklyn on Monday.

Traffic on major roadways was moving well Friday morning, according to the state Department of Transportation website, informny.com.

The Long Island Rail Road was reporting good service at its site, mta.info/lirr.

With William Murphy