"The chances of a direct U.S. hit from Melissa are low right now, but it is still an option, should the tropical system make it into the western Caribbean," said AccuWeather Lead Hurricane Expert Alex DaSilva.

The U.S. Government shutdown has hit three weeks, as it becomes one of the longest in history.

"Flooding is historically the deadliest calling card of tropical systems in this part of the world, and the threat Melissa brings will be no exception."