Mercedes will unveil their final upgrades for the 2024 Formula 1 season at the United States Grand Prix but Lewis Hamilton fears they face an ‘almost impossible’ scenario. The Silver Arrows have utilised F1’s unofficial autumn break to produce new parts they hope will spark a positive upturn entering the run-in. Formula 1 will close the year with two triple-headers but Mercedes have little to play for after a difficult run of results since the summer. Fourth place in the constructors’ championship is where Mercedes rank and is likely to be all the Brackley crew will seal. They trail Ferrari in…