In the Gulf, Invest 98L has a low chance for development, before it moves inland over northeastern Mexico or southern Texas by late Friday. The National Weather Service in Brownsville, Texas, said regardless of tropical development, locally heavy rain and increased swells "will be a concern" along the Texas coast.

Hurricane status is likely to be achieved soon as Erin continues to organize and strengthen. Once winds reach 74mph it will be classified as a Category 1 hurricane. The Saffir-Simpson Scale helps us categorize the strength of tropical systems.

Tropical Storm Erin is expected to strengthen, but will the storm be a direct hit to Delaware and the East Coast? See models, the latest updates here.