Flood advisories are up for Philly and the Shore even though it’s not going to rain. Blame the supermoon.

Flood advisories are up into Saturday for the Jersey Shore and along the Delaware River from the mouth of the Delaware Bay to central Bucks County, and you can blame one of the year’s astronomical highlights for any inconvenience.

The moon, which is making a close approach to the Earth and will be knighted a “supermoon” when it reaches fullness at 4:21 p.m. Friday, seven minutes before it rises, has been adding an extra boost to water levels along the Atlantic Coast and the tidal Delaware, with an assist from onshore winds.

The flooding is expected to be at the “sunny day level” — a type that NOAA says has been on the increase. The National Weather Service says it might result in “some partial or full road closures.”

However, it’s possible that some areas in the beach towns of Cape May County could experience more serious “moderate” flooding, said Lee Robertson, a lead meteorologist at the weather service office in Mount Holly.

The weather service advisory expects the minor flooding around the times of high tides along the Delaware, the Atlantic Ocean, and Barnegat Bay.

The high tides on the Delaware in Philly occur at 1 p.m. on Friday and Saturday. The oceanfront high tides are at 6 a.m. on both Friday and Saturday.

Along the bay shores, high tides will be 6 a.m. and 7 p.m. on Friday, and 7 a.m. Saturday.

Robertson said that on Wednesday night he was putting air in his tires, mildly deflated by the recent chill, when it occurred to him: “I don’t really need my flashlight.”

When the full moon is this close — it will be within 225,000 miles of Earth when it reaches the instant of fullness Friday — it appears about 30% brighter than it does when it’s farthest away.

Plus it’s about as high in the sky as it gets: Its career is the mirror opposite of the sun’s, which is sinking ever lower on the way to the winter solstice.

This is the last supermoon of 2024, and it still will be at 99% fullness when it rises at 5:04 p.m. on Saturday, and 96% at moonrise Sunday, at 5:57 p.m.

A perhaps unfortunate byproduct of the show is that the proximity to the Earth also bumps up the moon’s gravitational powers to tug at the tides.

Worldwide warming also has been contributing to nuisance flooding, and a NOAA report published in 2022 said the Northeast was seeing twice as many days of high-tide flooding as compared with 2000.

In part that would be the result of rising water levels worldwide from rising global temperatures and melting glaciers.

That remains anyone’s guess.

New Jersey on Wednesday declared a drought warning and called for voluntary water restrictions. Philadelphia and its neighboring counties are under a drought watch.

With its weekly update on Thursday, the U.S. Drought Monitor had almost all of eastern Pennsylvania in “severe drought,” as was all of New Jersey, except for southeastern portions of the state, which were in “extreme drought.”

A rash of brush fires have erupted throughout the region and the weather service says more are possible Friday afternoon as humidity drops and winds increase.

NOAA’s Climate Prediction Center sees the odds favoring normal rainfall in the period from Nov. 22 through Thanksgiving, and Robertson said some rain is possible middle to late next week

But it’s going to take a deluge or two, or three, to wipe out the prodigious precipitation deficits in the region. Philly has received 8% of its normal precipitation in the last 60 days, according to the weather service’s Middle Atlantic River Forecast Center.

Robertson said he wouldn’t be shocked if Philly received two inches of snow before it saw two inches of rain. (But no snow is in the forecast either.)

Staff writer Frank Kummer contributed to this article.