Brian Williams had arrived at London’s Heathrow airport, picked up his bags and was on his way to NBC’s Royal Wedding encampment when the damage and death toll from last night’s southern storm began to sink in.

“Our NBC News staff in London was just awakening to the news from home,” writes Williams on his blog. “Minutes later, NBC News President Steve Capus made the call: He said I should go home. We both agreed the tragedy would dominate our newscast and our coverage.”

Williams will anchor “NBC Nightly News” from New York tonight and then travel with Lester Holt to hard-hit Tuscaloosa, Alabama for tomorrow’s broadcast. NBC News correspondents John Yang and Thanh Truong are in Alabama, Mark Potter is in Georgia, and Ron Mott is in Mississippi. As NBC is part owner of The Weather Channel,  meteorologists Dr. Greg Forbes and Bryan Norcross will provide analysis to NBC’s coverage.

“I never got to see our infrastructure in London,” writes Williams, “or any of my colleagues beyond the confines of my car. We had a magnificent setup — the result of months of planning — to cover the big day in London, and we still will, live and wall-to-wall. But for now, for us, for this story, one of us had to go back and lead a separate coverage team—as the death toll grows.”

To date, more than 160 tornadoes covering 15 states have swept through the nation; the preliminary toll shows at least 250 deaths.