Tropical Storm Erin formed in the eastern Atlantic Ocean on Monday, forecasters said. The storm was expected to strengthen later in the week and could become the Atlantic's first hurricane of the season.

The hatched areas on the National Hurricane Center's tropical outlook map indicate "areas where a tropical cyclone — which could be a tropical depression, tropical storm or hurricane — could develop," said National Hurricane Center Deputy Director Jamie Rhome.

The last time a Hurricane Erin occurred was in 2001. The storm became a hurricane on Sept. 9. Erin was off the East Coast near New York on Sept. 11. NASA satellite images of the hurricane show smoke from the World Trade Centers blowing south.