MIAMI — Officials say Tropical Storm Helene is approaching islands off the western coast of Africa.

The National Hurricane Center in Miami said Saturday night that it expects Helene to produce tropical storm conditions for parts of the Cabo Verde Islands on Sunday.

As of 11 p.m. EDT, the storm was located about 155 miles (250 kilometers) southeast of the southernmost Cabo Verde Islands. The storm's maximum sustained winds are 60 mph (95 kph) and it is moving west at 13 mph (20 kph).

Officials say heavy rainfall on the islands could produce life-threatening flash floods.

A tropical storm warning and hurricane watch are in effect for the Cabo Verde islands of Santiago, Fogo, and Brava.