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A tropical storm is less likely to spin up this week from bad weather off the outer Caribbean islands.

And a dip in the jet stream is pushing wintry weather across South Carolina that will keep the Atlantic storm out to sea, forecasters said Monday.

The dip — a climate signal that winter weather patterns are setting in — is a big sign the 2018 hurricane season might be as good as done here.

Colder, blowing weather and rapidly cooling waters are turning off the jets. The Charleston Harbor water temperature on Monday was in the 60s. That's just not warm enough to sustain a tropical storm, said Charleston-based meteorologist Shea Gibson with the private company WeatherFlow.

The weather system was moving through the outer Caribbean islands Tuesday.

"It will turn north late this week well east of the U.S. coast and will have no impact on the Southeast," said meteorologist Jeff Masters, with the private company Weather Underground.

"We are transitioning to a more winter-like pattern and (the storm) is likely to be the final system we'll see become a tropical depression in the Atlantic this year," Masters said. A tropical depression is a weaker tropical storm. 

The worst the coast might get is rain and some wind from a Northeaster storm as the mess of weather passes by, Gibson said.

Meanwhile, the jet stream is pulling rain from the southwest ahead of it, and rainfall is expected to be heavy in the Midlands.

The National Weather Service forecasters in Columbia called for flooding on the Congaree River by Thursday. That's not likely to have much impact in Charleston.

The Edisto River is running 5 feet below flood stage. The Santee River might flood somewhat near Jamestown with releases from the dam on Lake Marion, where the Congaree empties.

The biggest chance could be a little local flooding in downtown Charleston on Thursday morning, the day the heaviest rain is expected, said meteorologist James Carpenter, with the Weather Service office in Charleston.

The National Hurricane Center on Tuesday dropped the chance to only 20 percent that the weather will become a tropical depression in the next few days. The chance had been 80 percent on Monday. But the storm fell apart moving into the Caribbean islands.

The Atlantic hurricane season doesn't officially end until Nov. 30. But fewer than 10 storms have formed after Nov. 10 across the entire ocean, Caribbean Sea and Gulf of Mexico in more than a century since the center began keeping track.

Once winter wind patterns establish, meteorologists say there's virtually no chance of a storm hitting the United States from the Atlantic and only a small chance of one from the Caribbean or Gulf of Mexico.

Reach Bo Petersen Reporter at Facebook, @bopete on Twitter or 1-843-937-5744.

Science and environment reporter. Author of Washing Our Hands in the Clouds.