Answer: The thesis statement: "DO NOT TRY TO OUTRUN A TORNADO IN YOUR CAR" would be the best way to introduce an essay comparing and contrasting the information on these websites.
Explanation: A thesis statement is a sentence that conveys the main idea of an essay, stating a concise concept for contrasting or comparing information. In this passage, FEMA claims that you should get in your car and drive to the nearest shelter, but in case the tornado is nearby, you must stop. On the other hand, CDC warns you not to get in a car by any circumstance. However, the sentence; "DO NOT TRY TO OUTRUN A TORNADO IN YOUR CAR" summarizes that both CDC and FEMA believe that you must not try to surpass a tornado by driving, since tornados could toss vehicles.