Tropical Storm Rafael is passing south of western Jamaica and is forecast to strengthen into a hurricane possibly by Tuesday evening.Rafael, which formed Sunday and was previously known as Potential Tropical Cyclone 18,

Tropical Storm Rafael was rapidly picking up steam on Tuesday afternoon as it chugged toward the Cayman Islands in the Caribbean, and will likely become a hurricane in the next few hours, according to the U.

Rafael is forecast to strengthen Tuesday and will likely become a hurricane over the next 24 hours as it batters the western Caribbean on the first leg of an uncertain journey toward the US Gulf Coast.