The weather forecast changed Wednesday afternoon and what had looked like a sunny Labor Day weekend locally changed to a potentially wet one as the summer vacation season comes to a close.

This time last year AAA predicted 35 million travelers for the 2015 holiday, 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 sunny weather forecast changed Wednesday afternoon after a tropical depression in the Gulf of Mexico was upgraded to Tropical Storm Hermine, the effects of which are slated to potentially bring storm-force winds and rain to Long Island over the holiday weekend.

Surf conditions at beaches on the South Shore of Long Island had improved by midweek after rough waters earlier, George Gorman, Long Island deputy regional director of state parks, said Wednesday.

“We had rip current advisories, and we had some restrictions, but conditions have improved,” Gorman said. “The lifeguards are still keeping people tight to shore.”

With temperatures expected to be moderate, somewhere in the mid-80s, Gorman said he did not expect big crowds. “Traditionally at this time of year it drops off,” he said. “Kids are going back to school. People are back at work.”

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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.

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.