(CNN) -- A tropical storm strengthened into a Category 1 hurricane Thursday in the Caribbean Sea, the National Hurricane Center said.
Hurricane Paloma was centered about 165 miles south of Grand Cayman Island Thursday evening.
Hurricane Paloma, packing winds of nearly 75 mph (121 kph), was centered about 165 miles (266 kilometers) south of Grand Cayman Island at 7 p.m. ET, the hurricane center said.
A hurricane warning -- meaning hurricane conditions are expected within the next 24 hours -- remains in effect for the Cayman Islands. The storm was moving north at nearly 12 mph (19 kph), and it is expected to strengthen and turn gradually northeast late Friday and Saturday.
The hurricane center said people in Cuba and Jamaica should monitor Paloma's progress.
The storm is expected to drop 4 to 8 inches of rain over the Caymans with isolated totals of as much as 12 inches possible.
The storm was a tropical depression off Nicaragua on Wednesday. It became a tropical storm Thursday morning.
Category 1 hurricanes have sustained winds of 74-95 mph.