MIAMI (AP) - A tropical storm warning was issued on Friday for parts of North and South Carolina as Ana approached the US coast, kicking up rough surf and rip currents ahead of what was forecast to be a rainy weekend.
The storm formed nearly a month before the Atlantic Hurricane season officially kicks off on June 1. The US National Hurricane Centre in Miami said that Ana's maximum sustained winds are near 45mph with slight strengthening forecast during the next day or so.
Hurricane Centre director Rick Knabb said that May storms are not unusual, with one forming every few years or so. But Ana marks the earliest subtropical or tropical storm to form in the Atlantic since another storm – also named Ana - in 2003, the Hurricane Centre said.
The storm is centred about 180 miles south-southeast of Myrtle Beach, South Carolina. The Hurricane Centre says it has been nearly stationary over the last few hours but is expected to move north-northwest later in the day.
The tropical storm warning is in effect from the south Santee River in South Carolina to Surf City, North Carolina.
Rain is a concern because the system is moving so slowly and won't clear out quickly. Ana is expected to deliver two to four inches of rain over the weekend, with some areas getting up to six inches.
Ana is currently a subtropical system, meaning it has characteristics of both a tropical storm, which gets its energy from warm ocean waters, and a traditional storm system driven by temperature changes.