Admiral Chester W. Nimitz, the new commander of U.S. forces in the Central Pacific, and his staff discussed the deciphered messages and agreed that the Japanese were likely initiating a major operation in the Southwest Pacific in early May with Port Moresby as the probable target. The Allies regarded Port Moresby as a key base for a planned counteroffensive, under General Douglas MacArthur, against Japanese forces in the South West Pacific area. Nimitz's staff also concluded that the Japanese operation might include carrier raids on Allied bases in Samoa and at Suva. Nimitz, after consultation with Admiral Ernest King, Commander in Chief of the United States Fleet, decided to contest the Japanese operation by sending all four of the Pacific Fleet's available aircraft carriers to the Coral Sea. By 27 April, further signals intelligence confirmed most of the details and targets of the "MO" and "RY" plans.