Hurricane Gaston, churning way out to sea, won’t be paying a visit to Long Island, but it is sending a calling card — a high risk for rip currents through Tuesday night and possibly through midweek, maybe even longer, forecasters say.

“The surf is dangerous for all levels of swimmers,” according to the National Weather Service’s beach forecast webpage, with surf height of 3 to 4 feet.

“High risk for rip currents and rough seas along the South Shore,” says News 12 Long Island meteorologist Rich Hoffman. “Be careful swimming.”

That’s as tropical disturbance and storm activity has picked up in the Atlantic basin, he said, also with a tropical depression that’s just east of the Carolinas, expected to stay to the south of Long Island, contributing to “rip currents and larger waves through the midweek.”

Beachgoers are strongly advised to stick close to lifeguards, ask them about conditions and heed the advice of beach officials, said Nelson Vaz, weather service meteorologist based in Upton. Meteorologists may know the conditions that lead to increased rip current activity, he said, but lifeguards are the ones who “know their local beaches the best.”

At play, he says, is Hurricane Gaston, “a big wind-maker out there,” creating swells that are piling water up along the mid-Atlantic coast. In the case of sandy beaches such as those of Long Island and New Jersey, he says, the water gets “trapped on the landward side of sandbars,” has “to find a way out” through cuts in the sand and creates strong rip currents in the process.

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Conditions are similar along the Delaware and New Jersey shores, Vaz said.

Swells from tropical systems have arrived, and, besides enhancing the chance for dangerous rip currents,“can also knock swimmers and waders into the sand,” says a beach hazards statement issued Monday by the weather service’s Mount Holly, New Jersey, office.

Thanks to tropical cyclone activity and periods of onshore wind, waters “will be rough at times this week” at New Jersey and Delaware beaches, the statement said, “and possibly through the Labor Day weekend as well.”