Erin is expected to develop into a hurricane later this week and could affect Puerto Rico, the Virgin Islands and the northern Leeward Islands.

The Atlantic basin includes the northern Atlantic Ocean, Caribbean Sea and Gulf of America, as the Gulf of Mexico is now known in the U.S. per an order from President Trump. NOAA and the National Hurricane Center are now using Gulf of America on its maps and in its advisories.

Although the storm is expected to stay offshore, it will produce dangerous surf conditions for much of the Atlantic Coast this week, forecasters say.

JTWC projects 18W to reach minimal tropical-storm intensity in the next day or so, making a slow, gentle curve northeast, weakening to a tropical depression and passing about 35 miles north-northwest of Sasebo at mid-afternoon Friday.