Late on July 18 , the National Hurricane Center ( NHC ) said that a tropical depression was forming . At 11 p.m. EST on July 18 ( 0300 UTC July 19 ) , it was classified as Tropical Depression Three , about 65 miles ( 105 km ) to the southeast of Charleston , South Carolina . Late on July 18 , the National Hurricane Center ( NHC ) remarked that a tropical depression was developing , with its convection becoming more concentrated around a circulation ; at 11 p.m. EST on July 18 ( 0300 UTC July 19 ) , it was classified as Tropical Depression Three , about 65 miles ( 105 km ) southeast of Charleston , South Carolina .