A low pressure area formed to the south, and southwest, of Bermuda on April 18. A trough, which is a type of weather system, brought an area of clouds into the low pressure system. The low pressure system moved towards the north. After turning towards the northwest, the weather system looped southeastward. Thunderstorm activity became stronger near the center of the cyclone. The storm was named Subtropical Storm Ana on April 20, while located about 250 miles (400 km) west of Bermuda.