A desperate search and rescue operation launches after a tourist submersible carrying five people, who paid to see wreckage of the Titanic, disappears. The US Coast Guard is one of the multiple-teams scouring the Atlantic Ocean in a race against time. Plus, Donald Trump offers up a new defense of why he didn't turn over classified documents at the end of his term as president. And, the Texas Senate is expected to set the ground rules in the impeachment trial of former Texas Attorney General Ken Paxton. Also this morning: a tropical storm brewing over the Atlantic is expected to strengthen into a hurricane by tomorrow, and have you had your BMI checked lately? Why it may not be the best barometer to gauge your health risks.To learn more about how CNN protects listener privacy, visit cnn.com/privacy