Flooding rains, gusty winds, and coastal flooding are likely to impact millions of the Caribbean islands as Tropical Storm Rafael, the 17th named storm of the Atlantic hurricane season, picks up steam through Tuesday and Wednesday.

Rafael strengthened into a hurricane Tuesday evening as it lashed the western Caribbean with strong winds and heavy rain. The storm is expected to keep strengthening before it makes landfall in Cuba on Wednesday.

Tropical Storm Rafael formed in the Caribbean on Monday and is forecast to become a hurricane on Tuesday. It could approach the U.S. by mid to late week.

Tropical Storm Rafael gained steam late on Monday as it churned northward toward Cuba, which is still struggling to recover from a nationwide blackout and hurricane two weeks ago.

Rafael has undergone rapid intensification and is expected to be a major hurricane before it makes landfall in Cuba later today,” forecasters with the Hurricane Center said Wednesday. “Rafael could briefly weaken over Cuba but is expected to emerge into the southeastern Gulf of Mexico as a hurricane.

Rafael was expected to continue to pass by Jamaica through Tuesday afternoon, be near or over the Cayman Islands on Tuesday night, and make landfall in Cuba on Wednesday.

A disturbance in the Caribbean strengthened Monday afternoon into Tropical Storm Rafael, which is forecast to become a hurricane Tuesday.

Tropical Storm Rafael has strengthened to near hurricane intensity as it barrels toward the Cayman Islands and Cuba, where it was forecast to hit as a full hurricane.