Coastal flooding forecast into the weekend with siege of winds and waves from off-shore storm
Winds could gust past 35 mph at the Shore, whose beaches are likely to lose some sand. But rain deficits will persist.
It isn’t a classic nor’easter, but a stalled storm spinning off the coast is doing a decent impersonation, buffeting the Jersey Shore with a prolonged spell of gusting winds and pounding waves that is expected to lap well into Friday night, forecasters say.
The National Weather Service has posted a coastal flood advisory in effect until 11 a.m. Thursday, but flooding could become more serious Thursday night and Friday morning.
A coastal-flood watch has been hoisted for the period from 4 p.m. Thursday until 11:59 p.m. And, “it’s possible the watch will be extended,” said Jonathan O’Brien, a meteorologist at the National Weather Service in Mount Holly.
Minor coastal flooding is possible along the Delaware at high tides Thursday into Saturday.
While rain hasn’t been prodigious — less than a tenth of an inch in the city, and just under 0.2 in Atlantic City — gusts up to 36 mph are possible at the Shore.
But the big factor in generating the flood threat will be duration. “Moderate flooding” is possible Thursday evening and Friday morning, the weather service said.
The winds have shifted from an onshore direction — from the northeast — to more northerly.
To have significant erosion, “you don’t need an onshore wind,” said O’Brien’s colleague, Alex Staarman. In this case, the persistence of the strong and frequently gusty winds are factors.
Ocean waves can be voracious beach-eaters, and “the wave heights are going to continue to increase with time,” Staarman said. The forecasts are calling for the spell of high winds to continue well into Saturday night.
They would be the result of an amalgamation of forces, including a storm building off the mid-Atlantic coast and a high-pressure system in southeastern Canada, meteorologists said.
Ordinarily, the heavier air of high pressure suppresses clouds and rain; however, the region is going to get caught in an air sandwich between the high and low pressures off the coast. It is the pressure difference that generates winds.
In addition, the waxing moon, which will be full on Sunday, could add an astronomical kick to any flooding, Staarman said.
For all that, by Sunday, it is unlikely that the region will have experienced much of a dent in its rain deficit.
Only about 1.3 inches of rain has fallen officially in Philadelphia since Sept. 1.