Tropical system strengthening in the Atlantic. Will it mean a hurricane for Hilton Head?

A tropical disturbance in the mid-Atlantic is steadily increasing its likelihood of developing into a tropical depression, according to the National Hurricane Center .

On Wednesday morning, the large tropical wave near the Lesser Antilles had a 60% chance of formation within the next seven days, the center said, and there was no chance through the next 48 hours. A tropical disturbance becomes a tropical depression when the storm has maximum sustained surface winds of 38 mph or less.

“Environmental conditions are forecast to gradually become more conducive for development while the system moves generally west-northwestward over the Greater Antilles and towards the Bahamas,” the NHC said Wednesday.

The center predicted the disturbance could strengthen into a tropical depression by the weekend while it’s near the Greater Antilles, Bahamas, or close by Florida. But because the disturbance has not yet developed, Jonathan Lamb, a meteorologist with the National Weather Service’s Charleston Office, said there’s a lot of uncertainty about any potential impacts to the Lowcountry.

There is a lot of variation in forecast models and an infinite array of possibilities, Lamb said Wednesday.

Some models suggest the system could pass near Florida’s east coast over the weekend as a tropical depression or tropical storm, according to reporting by the Miami Herald. If the disturbance develops into a tropical storm, it would be called Debby.

It’s also possible the tropical disturbance may not develop, Lamb said.

What’s clear for the Lowcountry is continuing oppressive heat. Beaufort County was under a heat advisory until 8 p.m. Wednesday, warning of expected heat index values as high as 110 degrees.

On Thursday and Friday, temperatures will be even higher, Lamb said, with heat indices between 110 and 115.