Tropical Storm Lee expected to become the next major hurricane, it is expected stay in the Atlantic while becoming a category 4 storm. Tropical Storm Lee formed Tuesday afternoon in the Atlantic Ocean. The National Hurricane Center's forecast path shows the storm becoming a major hurricane late this week and approaching the northern end of the Caribbean Sea near the Leeward Islands by this weekend. At that point, it could be a Category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale, which would mean winds of 130-155 mph.