Tropical Storm Erin is continuing to pick up strength as it moves across the Atlantic, with forecasters expecting the storm to officially strengthen into a hurricane on Friday, Aug. 15, according to the National Hurricane Center.

Tropical Storm Erin is expected to become a hurricane later today, Aug. 15, and a Category 4 hurricane with maximum sustained winds of 130 mph over the weekend. A major hurricane is a Category 3 or stronger, with maximum sustained winds of at least 111 mph.

Erin has strengthened to become the first hurricane of the Atlantic season. It could become a major hurricane this weekend.