MIAMI (AP) -- Early surprise Ana muscled up to a tropical storm as it plodded toward the Southeast coast early Saturday, threatening to bring the Carolinas drenching rains and dangerous surf after forming weeks ahead of the formal June 1 start of the Atlantic hurricane season. The U.S. National Hurricane Center in Miami said Ana was centered at 5 a.m. EDT Saturday about 115 miles (170 kilometers) south-southeast of Myrtle Beach, South Carolina. Ana has sustained top winds of 60 mph (95 kph) while moving north-northwest at 3 mph (6 kph). Forecasters say a tropical storm warning extends from south Santee River in South Carolina to Cape Lookout, North Carolina. Ana is forecast to deliver 1 to 3 inches of rain, up to 5 inches in scattered spots, and drive potentially life-threatening surf.