Ophelia’s leftovers will bring more rain to the Philly region, and ‘supermoon’ tides have prompted flood advisories

The persistent remains of Ophelia are forecast to add juice to rains across the region Friday, and with the “supermoon” swelling the tides, flood advisories are up for the Jersey Shore, all of South Jersey, and for Philadelphia and areas along the Delaware River.

“It’s kind of just coming back around,” Patrick O’Hara, a meteorologist at the National Weather Service Office in Mount Holly, said of Ophelia, which is becoming something akin to a nagging cold.

A storm brewing off the Carolina coast on Thursday was forecast to ingest Ophelia’s soggy remnants then track northward, throwing back heavy rains, especially north and east of Philly. The rains were expected to begin Thursday night, with the heaviest falling late Friday morning, the weather service said.

A flood advisory was posted for all of South Jersey and Delaware, and areas along the Delaware River, for early Friday, with more minor flooding possible Saturday. At the Shore, minor flooding was expected around the times of high tide Thursday night through Saturday night.

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At that level, flooding can lead to “some partial or full road closures,” the weather service said.

While Philadelphia may miss the heaviest of the rains, a flash flood watch was up for the Trenton area and New Jersey counties to the north. O’Hara said that could be expanded. “All that moisture is supposed to squirt up northwest,” O’Hara said.

“The tidal stuff is kind of going crazy, too, with the full moon,” he said.

With the moon making one of its closest approaches to Earth of the year — thus the “super” designation — and reaching 100% fullness just before 6 a.m. Friday, its influence on the tides will be near an annual maximum, according to NOAA data.

Plus, steady winds from the northeast will continue to drive waves onshore and inhibit drainage of the congested back bays.

The region has experienced a near weeklong sea breeze, the result of high pressure, or heavier air, to the north that has been generating winds from the east and northeast as part of its clockwise air movement.

Winds — gusting to maybe 25 mph on the mainland and 35 mph at the Shore on Friday — won’t be in a league with those of last weekend, nor should the rains, at least in the immediate Philadelphia area.

Rainfall amounts of 2.5 to 4 inches were common throughout the region last weekend as Ophelia approached from the south.

What was left of it sagged off the Jersey coast early in the week and meandered south. But with the warm Atlantic water temperatures, some of Ophelia’s moisture managed to survive.

“The gift that keeps on giving,” said Dave Dombek, senior meteorologist with AccuWeather Inc.

That moisture is forecast to add some potency to the storm.

“That’s a lot of juice in the air,” Dombek said. “You’re bringing in some deeply moist air.”

» READ MORE: Ophelia's rains doused rain deficits in the region

The clouds that returned Thursday are due to persist through Friday night, playing spoiler for the last supermoon of 2023, when the moon’s proximity makes it appear about 30% brighter than when it is farthest away. This is also the “harvest moon,” so named because before the days of electricity, it gave farmers extra light for a little overtime during the harvest season.

While Friday night will be a cloud-out, the viewing should improve Saturday, when skies are predicted to be partly cloudy when the moon rises at 7:31 p.m., still at 99% fullness, and mostly clear Sunday when it still will be better than 90% full when it rises around 8 p.m.

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By the time that happens Sunday, said Dombek, the temperature may have approached 80 degrees under a daylong sun.

What’s more, he said, the sun should prevail Monday, Tuesday and Wednesday with highs of 80 or better.