A general view shows an empty beach as subtropical storm Alberto approaches Cancun, Mexico May 25, 2018. REUTERS/Israel Leal

(Reuters) - Subtropical storm Alberto is moving slowly and erratically over the northwestern Caribbean Sea and is expected to strengthen gradually over the next 48 hours as it heads to the Gulf of Mexico, the U.S. National Hurricane Center (NHC) said in its latest advisory on Friday.

The storm is located about 100 miles (160 km) south-south east of Cozumel, Mexico, packing maximum sustained winds of 40 mph (65 kph), the Miami-based weather forecaster said.

“Heavy rainfall expected to affect the Yucatan peninsula, western Cuba, Florida and the northeastern Gulf Coast through the weekend,” NHC said, adding “Alberto is forecast to slow down after it moves inland.”

It is expected to reach U.S. Gulf Coast on Monday