Tropical Storm Erin is forecast to strengthen into the first hurricane of the Atlantic season by Saturday morning and then become a major Category 3 hurricane by Sunday morning as it passes north of Puerto Rico. But as of now, Erin is not expected to pose a direct threat to the U.S.

The National Hurricane Center says Tropical Storm Erin is starting to gain strength over the Atlantic and should soon become a hurricane before intensifying into a major storm this weekend.

As of the latest update, issued at 4 a.m. CDT Thursday, Tropical Storm Erin was located about 990 miles east of the Leeward Islands and was on a path to the west at 17 mph. (The next update will come later this morning, and updates will become more frequent once watches and warnings go into effect for the storm.)