Police uncover messages from the suspect that may show a motive in the Las Vegas Cybertruck explosion as his ex-girlfriend shares new video with NBC News, federal authorities warn of potential copycat attacks after the deadly New Orleans attack, a massive snowstorm set to hit the U.S., and more in tonight's broadcast.

Major winter storm blasts much of U.S. with intense cold, blizzard conditions; Thousands of flights disrupted by massive winter storm; FBI releases new video of New Orleans truck attack suspect; and more on tonight's broadcast.