The first hurricane of the Atlantic season gained strength on Thursday is expected to attain Category 2 status as it reaches the North Carolina coast, where thousands of vacationers scrubbed their July Fourth holiday plans amid evacuation orders. Hurricane Arthur was about 110 miles (175 km) south-southwest of Cape Fear, North Carolina, with current maximum sustained winds of 90 miles per hour (145 km per hour), U.S. forecasters said. Moving faster at 10 mph (17 kph), the center…