On July 4, the system organized into a tropical depression about 120 mi (195 km) southeast of Cape Hatteras, North Carolina.[4] While in its formative stages, it dropped rainfall along the coast of the Carolinas, peaking at 4.11 in (104 mm) in Pinopolis, South Carolina.[5] The depression tracked northeastward due to a ridge over New England, and the cyclone passed just southeast of the Outer Banks. After a Hurricane Hunters plane observed gale-force winds, the depression was upgraded to Tropical Storm Arlene late on July 5; in the post-season summary, meteorologist Neil Frank noted, "the surprising element in the development of Arlene was the rapidity of the transformation process."[4]