MIAMI (AP) — Tropical Storm Chantal formed off the southeast U.S. coast and was forecast to bring heavy rains to parts of the Carolinas on Saturday. Tropical storm warnings were issued for portions of the two states, the National Hurricane Center in Miami said.

The storm’s center was located about 65 miles (105 kilometers) east of Charleston, South Carolina, on Saturday night, and 120 miles (190 kilometers) south-southwest of Wilmington, North Carolina. Its maximum sustained winds were clocked at 50 mph (85 kph), and it was moving north at 8 mph (13 kph).

Rain bands from Chantal were moving over the coast, the hurricane center said, and the storm’s center was expected to move over South Carolina overnight or early Sunday with flash floods an increasing concern. The storm was expected to weaken rapidly after landfall.

Heavy rain was forecast for the coastal plain of the Carolinas through Monday — total rainfall of 2 to 4 inches (5 to 10 centimeters), with local amounts up to 6 inches — threatening flash flooding.