At the conclusion of WWI, CAPT Yarnell was awarded the Navy Cross,[2] for his "distinguished services in the ... Office of the Chief of Naval Operations, and on the Staff of the Commander, U.S.

[3] Yarnell then rotated between sea and shore duty until ordered to the aircraft carrier USS Saratoga in September 1927, as prospective commanding officer.

While in that capacity, advising the General Board on the design of a fleet submarine, Yarnell opposed smaller types, presciently noting, "our prospective opponent [Japan] has always started operations by attacking before a declaration of war".

Rear Admiral Yarnell commanded the carriers Lexington and Saratoga in an effort to demonstrate that Hawaii was vulnerable to naval air power.

With a storm as cover, at dawn on Sunday, 7 February, Yarnell's 152 planes attacked the harbor from the northeast, just as the Japanese would ten years later.

The Navy's war-game umpires declared the attack a total success, prompting Yarnell to strenuously warn of the Japanese threat.

[8] After three years' service commanding the Asiatic Fleet, Admiral Yarnell was transferred to the Retired List, and was elected an honorary member of the Rhode Island Society of the Sons of the Revolution on February 22, 1940.

On 1 November 1941, as war loomed, Yarnell was recalled to active duty and worked in the office of the Secretary of the Navy as Special Adviser to the Chinese Military Mission.