Hurricane Erin could 'at least double or triple in size' next week and the track has shifted south, but remains likely to turn away from the East Coast.

Hurricane Erin exploded in strength to a Category 5 storm in the Caribbean on Saturday, rapidly powering up from a tropical storm in a single day, the National Hurricane Center said.

A westward-moving tropical wave could produce an area of low pressure in the tropical Atlantic late in the week of Aug. 18, the hurricane center said on Aug. 16. The center shows a 20% chance of storm formation over the next week.