Nor’easter giving Philly-area moms the cold, damp shoulder. Flood advisories in effect for Sunday

No, Mother’s Day wasn’t moved to March this year. It just feels that way.

A potent and stubborn nor’easter adrift from the steering winds in the upper atmosphere will continue to pester the region with persistent onshore gusts into Monday, importing quite chilly air from an Atlantic Ocean that is still recovering from winter.

A coastal flood warning was in effect for the Jersey Shore until 7 a.m. Sunday, and the water-jammed back bays could be especially problematical, said Sarah Johnson, a lead meteorologist at the National Weather Service in Mount Holly.

The agency said the sloshing waters might shut off roads and cause some structural damage. Minor flooding is possible during the next several tidal cycles, the agency said.

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A flood advisory was up for areas along both sides of the Delaware River from 6 to 11 a.m. Sunday, with the river at Washington Avenue due to crest near “moderate” flood stage.

At least the winds are supposed to back off, and top gusts will be a mere 30 mph on the mainland and 40 mph at the Shore, and Johnson said the rains for this region should call it a storm by early afternoon.

“Rain should be moving out throughout the day,” she said. “It should be completely dry by the early evening.”

But the sun will remain a rumor, and after experiencing its lowest maximum temperature for a May 7 in 55 years, Philly is on track for its chilliest May 8 in 75 years. “It’s not going to be a gorgeous day,” Johnson said Saturday, “but maybe better than what we’re seeing today.”

Talk about a low bar.

Winds gusted to 63 mph in Atlantic City on Saturday, where a high-wind warning remained in effect until the early-morning hours of Sunday. Several locations throughout the region reported more than 2.5 inches of rain, with close to 3 in King of Prussia, Montgomery County.

The regional unpleasantness forced postponement of outdoor events, countless yard-work projects (OK, so it wasn’t all bad), and the Phillies-New York Mets game (we’ll withhold comment), which will be played Sunday as part of a single-admission doubleheader.

Saturday evening more than 10,500 Peco Energy and Atlantic Electric customers were without power, and trees came down throughout the region as the winds picked up after the rain had soaked the ground.

However, the region also caught a few impact-blunting breaks.

For one thing the trees in many places aren’t fully “leafed out,” said Johnson, thus not as heavy as they would be in midsummer, and that likely kept down the power-loss numbers.

Plus, at the onset of the rains, river and stream levels were relatively low. That’s because after quite a juicy start to April, the atmospheric spigot basically shut off after the 18th, pointed out Dave Dombek, senior meteorologist at AccuWeather Inc. With the thirsty foliage growing ever greener, the soils were drying out.

And the moon phase is not in prime tide-tugging mode. Still, with those persistent onshore winds from the east, flooding is likely to cause some “significant impacts” at the Shore on Sunday, Johnson said.

“We have quite a few areas that could see moderate flooding,” she said. “For back bays this is going to be probably particularly impactful because the water isn’t going to have a chance to evacuate.”

Conditions should slowly improve after Sunday, forecasters promise, as the storm pursues a change of venue — in its own idiosyncratic way.

Typically, coastal storms end their careers spinning over the ocean well northeast of the Mid-Atlantic. Not this one.

“It’s actually going to slowly drift south on the Eastern Seaboard,” said Dan Pydynowski, an AccuWeather senior meteorologist, making for a rather unpleasant week for the Maryland and Virginia beaches.

The storm is cut off from the west-to-east steering winds in the upper atmosphere, he said, something that tends to happen this time of year as those jet-stream winds, which form at the boundaries of warm and cold air, retreat to the north.

The winds from this particular iteration have been getting a kick from the high pressure or heavier air to the north, which also has been blocking the storm from progressing northward. The rising air in storms, contrary to popular perception, tends to be lighter, and those pressure differences drive the winds.

The winds are off the ocean because air circulates clockwise around high centers, and counterclockwise around lows. Ocean temperatures are in the mid-50s, which is why it is so chilly.

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Philly’s high Saturday, 54, was the lowest for a May 7 since 1967. Sunday’s forecast high, 52, would be about 20 degrees below normal and the lowest for a May 8 high since 1947.

But during the workweek we’ll be getting a lesson in the power of the sun, whose strength is approaching its annual apex — this is the onset of the “solar summer,” said Pydynowski, a roughly 90-day period centered on the solstice.

Those winds are going to continue blowing off the ocean through Friday, but with the return of sunshine, highs Monday will be in the low 60s, in the 70s the next four days, and perhaps up to 80 on Saturday.

And if we can trust the government’s Climate Prediction Center, we are done with March, at least for now.

The extended outlook through the first three weeks of May favors above-normal temperatures here and in most of the nation.