U.S. Grand Prix second practice cancelled

By Alan Baldwin AUSTIN, Texas (Reuters) - Thunder, lightning and torrential rain washed out second practice at the U.S. Formula One Grand Prix on Friday after Nico Rosberg went fastest for Mercedes in a largely meaningless morning session. Rosberg's championship-leading team mate Lewis Hamilton, who can seal his third world title on Sunday at the Circuit of the Americas, did only four timed laps in total and was fifth overall. The forecast for Saturday, when qualifying is scheduled, was of more