Water is a fact of life for workers at the Charleston City Marina, but they hadn’t witnessed the likes of Thursday’s tidal flooding in about two years.

Flooding likely again today

Flooding is expected in downtown Charleston again this morning, but it shouldn’t be as bad as Thursday, according to the National Weather Service.The Weather Service issued a coastal flood advisory for 7 a.m. to noon. The tide in the Charleston Harbor is expected to be up 71/2 feet this morning, enough to push water onto streets.During Thursday morning’s nasty flooding, the tide was up 9.73 feet, according to the Weather Service. It also was raining Thursday morning, adding to the flooding problems. Some drizzle is expected this morning before 8 a.m.Today’s forecast calls for a mostly cloudy day, with a high near 61 and lows near 40. Northeast winds will be from 5 to 10 mph.The forecast for Saturday and Sunday calls for cloudy skies, a 20 percent chance of showers. Highs will be near 60 and lows about 40 with northeast winds from 10 to 15 mph.

The Ashley River spilled into a parking lot near the marina office around high tide at 8:30 a.m. As the flooding receded, it left behind twigs, red Solo cups and other refuse that had been floating in the water.

Floodwaters submerged and disabled electrical equipment, causing an outage to a portion of the docks.

“Clearly, it was a higher tide than we see typically,” said Nick McGinty, general manager of the Lockwood Drive marina. “It’s one of those things you see every other year.”

To blame: the moon and wind.

Bob Bright, a meteorologist with the National Weather Service in Charleston, said the new moon was at its perigee, or the point in its orbit that’s closest to Earth. When the natural satellite is at its perigee as a full moon, observers can see what has been dubbed the “super-moon.”

The astronomical factor combined forces with a steady northeast wind and rough seas.

“With the moon closest to Earth at this time and winds basically keeping the water pushed toward the coast, that’s leading to high tides and flooding,” Bright said.

More minor flooding is expected this morning, as the National Weather Service has issued a coastal flood advisory from 7 a.m. to noon. High tide at Charleston Harbor is forecast to be about 71/2 feet.

Thursday’s phenomenon, called a perigean spring tide, flooded Morrison Drive in downtown Charleston. Water surrounded a dozen homes on South Street and neared the doorways of several residences.

Minor flooding also was reported on 12th and 25th streets on Isle of Palms.

Rainfall didn’t contribute greatly to the problem, Bright said.

Coastal areas saw about a half-inch early Thursday. The heaviest downpours were associated with some thunderstorm activity farther inland.

Weather should be drier today, though a 20 percent chance of rain is still forecast.

It’s fortunate that the high tides were not coupled with a significant storm system, Bright said.

In 1962, a storm surge and a perigean spring tide inundated the coastline from South Carolina to Cape Cod. About 40 deaths were attributed to the weather event.

Thursday’s event reared its head mostly as an inconvenience for Lowcountry motorists, as evidenced in residents’ Twitter posts.

“It doesn’t just rain in Charleston,” Lindsay Wooles tweeted, “it floods.”

“People in Charleston can’t drive in the rain,” groused a man named Mike D.

Reach Andrew Knapp at 937-5414 or twitter.com/offlede.