An area of thunderstorms formed into a tropical depression Friday afternoon, and forecasters issued a Tropical Storm Warning for the South Carolina coast on the first holiday weekend of the summer.
Forecasters said they expect the system’s main impact will be heavy rain and dangerous rip currents. The system, which will be named Bonnie when it reaches tropical storm status with 39 mph winds, is forecast to make landfall Sunday afternoon near Charleston with top winds of 45 mph.
Late Friday afternoon, the center of the storm was about 435 miles southeast of Charleston. Top winds were 35 mph, and the system was moving west-northwest about 13 mph.
The Tropical Storm Warning extends from the Savannah River north to Little River Inlet, covering the entire South Carolina coast. But authorities warned that rip currents and rough surf could be a problem farther north, along the North Carolina coast.
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The storm’s potential impact on the Charlotte area is still unclear. Stacy Stewart of the National Hurricane Center said most computer guidance Friday indicated the steering current that takes the storm onto the South Carolina coast will weaken Sunday. Stewart said the current forecast calls for the storm to slowly wander northward along the Carolinas’ coast Sunday and Monday, while weakening.
Such a scenario would keep most of the heavy rain and thunderstorms east of the Charlotte region. But the National Weather Service office in Greer, South Carolina, said it expects a 50 percent chance of showers and thunderstorms Sunday for Charlotte, and a 60 percent chance for Union and Cabarrus counties, closer to the storm circulation.
The weather is a major factor this weekend in the Charlotte area, with more than 100,000 racing fans expected to attend Sunday evening’s NASCAR Sprint Cup race at Charlotte Motor Speedway.
“The amount of rainfall in the immediate Charlotte area really depends on how strong the (tropical) storm is,” said Josh Palmer, of the National Weather Service office in Greer, South Carolina. “The stronger the system, the farther inland we can expect the showers and thunderstorms to move.”
But Palmer said the presence of the tropical system nearby, combined with the rather unstable atmosphere already in place across the western Carolinas, is likely to trigger some showers and thunderstorms.
At the coast, where tens of thousands of people are expected to visit for the Memorial Day weekend, authorities warned beachgoers to use caution in the water. The National Weather Service office in Wilmington issued a “moderate” rip current risk for Saturday, and said it could increase Sunday.
Up to 4 inches of rain could fall from the system.
Steve Taylor, of the National Weather Service office in Charleston, said the heavy rain could be a problem in that coastal city.
“As we know, heavy rain, especially at the time of high tide, can cause flooding in the city,” Taylor said.
With the storm’s expected slow movement once it reaches the coast, meteorologists said persistent heavy rain showers could cause flooding problems through Monday.