 Welsh served as Air Officer Commanding-in-Chief of Reserve Command from April 1940, as Air Officer Commanding-in-Chief of Technical Training Command from May 1940 and as Air Officer Commanding-in-Chief of Flying Training Command from July 1941.Overseeing Eastern Air Command in 1942, Welsh was responsible for providing air support for allied forces in Algeria and Tunisia during Operation Torch.Welsh would later lead the RAF delegation in Washington, D.C. during 1943 and 1944 before his resignation on 1 December 1944.