The tropics are heating up once again. Late Monday afternoon, Tropical Storm Rafael formed over the Caribbean Sea. After starting the day with a ragged, disorganized appearance, Rafael’s structure organized somewhat during the afternoon, and thunderstorm activity consolidated near its center — a sign of a strengthening storm.

Tropical Storm Rafael gaining strength Tuesday morning after forming in the Caribbean Sea, with forecasters saying it will strengthen into a hurricane with predictions the storm is headed for the U.S.

The tropical depression Eighteen is headed for the Gulf Coast and likely to transition into a tropical storm Monday and a hurricane by Wednesday.