Top computer forecast models haven't reached a consensus on Melissa's next move. One possible scenario calls for the storm to dramatically strengthen.

A tropical wave that moved into the eastern Caribbean on Sunday – designated Invest 98L by the National Hurricane Center on Saturday – is becoming increasingly organized and will likely become a tropical depression or tropical storm in the next day or two as it slows over the central Caribbean.

The system was located over the central tropical Atlantic as of 1 p.m. Thursday, and forecasters said they expect it to continue moving west at 15 to 20 mph over the next several days. It could develop more once it reaches the warm waters of the Caribbean, forecasters said.

Invest 98L in the eastern Caribbean is expected to strengthen into a tropical depression or tropical storm over the next few days.

The National Hurricane Center said there’s a medium chance (60 percent) that a tropical depression will form in the Caribbean Sea later this week. Whenever a system forms in the Caribbean hurricane-watchers in the U.S. take notice, because there’s a chance the system could end up affecting the Gulf or U.S. East Coast.