First of all, the claim made in 1942 that the Allies may win WWII is an about face of what was taught as recently as December 1941. The Watchtower, edited by Joseph Rutherford, published a lengthy series of articles (entitled "Demon Rule Ending") that autumn interpreting the "King of the North" vision from Daniel as a window into what lies in the near future. In these articles, the author (whether Rutherford or Fred Franz) foretold that the neither Axis nor Allied Powers would win the war in victory but that both sides would form, with the totalitarian Axis Powers taking the dominant role, an armistice leading to a "new League of Nations" through which the cry of "peace and security!" would call forth. Through these events, all nations would become totalitarian states like the Axis Powers. This draws on the declaration made by the Axis Powers in November 1940 to establish a "new League of Nations" when the war is finished. Rutherford moreover had been teaching since 1938 (in Face the Facts) that the Axis powers would succeed in obtaining Great Britain and the USA, and for an even longer time the Golden Age published articles on how the totalitarians were in the process of destroying the American government and replacing it with totalitarianism. All of these are mistaken predictions, if not "false prophecy". And the idea that the "abomination of desolation" will be realized by a "new League of Nations" was already in place, as expressed in the 15 December 1941 Watchtower (p. 373), which also connected this coming organization with the "beast" of Revelation 17:3-7.
Then two things happened in January 1942. One, Rutherford died and Nathan Knorr took control of the Watchtower Society. Two, the Allied Powers declared their intent via the Atlantic Charter to establish a "United Nations" for maintaining peace between nations after the war has ended. That spring, the Watchtower was full of articles emphasizing the closeness of Armageddon: "Armageddon is very near....Now we are near the FINAL END of the 'time of the end' ... Armageddon swiftly approaching ... Armageddon, now near ... The final gathering by the Lord is on ... The time is short" (1 February 1942, pp. 37-45), "Armageddon is at hand" (1 March 1942, p. 80), "Now with Armageddon immediately before us ... The world emergency with Armageddon at the door is the very time to most anxiously keep God's law and obey him" (1 May 1942, pp. 139-142), etc. I doubt statements like these from 1942 are emphasized today in the summer convention talks. Then in the 15 May 1942 issue of the Watchtower, the author wrote that the setting up of the abomination of desolation, which has been going on since 1919 (when the original League of Nations was formed), but which will be given definitive form in a totalitarian "new world order" is "a sure sign of the nearness of Armageddon" (p. 153). The same article also backpedaled on the earlier belief that the Axis Powers would hold the upper hand in ending the war. Now it is claimed that the Axis Powers may well be forced to compromise with the Allies: "[The Pope] wants to save something of advantage out of any possible failure of his scheme for world domination. He is willing to compromise with the anti-Axis forces should they gain military victory. While so doing he can try to shield his totalitarian puppets against total ruin and undoing" (Ibid.).
The emerging view on the post-war period was expounded in September 1942, both in a 1 September 1942 Watchtower and at the Peace -- Can It Last? talk at the annual convention. The idea that the war would end in a peace pact goes back to the 1941 view, but Knorr no longer claimed that the war would end without a definitive victory for either side. It was now implied that the Allied Powers would attain victory, as it is their United Nations (as opposed to the Axis Powers' "New League of Nations") that would administer the post-war period as the "beast" that comes out of the abyss of inactivity. But in claiming that this understanding was obtained "by Jehovah's unerring spirit" (as stated in the 15 July 1960 Watchtower), the Society omits some important details about how Knorr conceptualized this post-war United Nations. First of all, Knorr conceived of the United Nations as a powerful organization that will run the affairs of the world. The Vatican would hold the UN together, "as a supranational power over the postwar confederacy of nations", and the Vatican would place armies all over the world that would keep the peace as a powerful international police force. This would be set up very quickly after the cessation of hostilities, for sudden destruction would follow after the declaration of "peace and destruction". And this leads to the second fact, which is that Knorr construed the post-war period as very, very short. In the 1 September 1942 Watchtower, it was published that "the 'battle of that great day of God Almighty' will break out suddenly upon the postwar builders when they think they can cry out, 'Peace and safety' " and that "man's postwar arrangement will not survive the battle of Armageddon" (p. 259). The Kingdom News of April 1943 similarly stated that "When the postwar builders cry 'Peace and safety!' then will break forth the battle and will destroy this old world" (p. 2). The 1943 booklet Fighting For Liberty on the Home Front made this prediction of the near future:
"Despite all declared aims and slogans of the United Nations, this curb against the free spreading of the truth will not stop with the end of the global war. God Almighty's own Word for it is that the opposition to Bible Christianity will not weaken in the postwar period, but will persist and strengthen. At the last it will bring the nations to the climax, the battle of Armageddon. For this reason, when the postwar builders get their political, commercial, religious structure erected and operating and begin to cry "Peace and Safety!" it will not mean a peace with the truth about Jehovah's Theocratic Government under his Christ. Therefore it will not mean a peace with or from Jehovah God. Suddenly complete destruction from God and by Christ will come upon the whole postwar arrangement, and organized religion will go down first. God's Word says so" (pp. 28-29).
Then when the war seemed very close to a finish in 1944, the Watchtower continued to stress the extreme closeness of Armageddon. The 1 March 1944 Watchtower referred to "this time immediately before Armageddon's war" (p. 77), and the 1 May 1944 Watchtower stated that "the day of Armageddon is very near ... This is the time of great emergency because the battle of Armageddon is very near" (pp. 141-142). The 1944 booklet Religion Reaps the Whirlwind declares that "that terrific whirlwind of annihilation is drawing near according to all the weather signals of God's Word" (p. 59-60). The rhetoric became even more intense after V-E Day (8 May 1945). In a talk delivered on 10 June 1945, Knorr urged: "There is no longer any time to wait, for the Kingdom of God is here! ... It is a day of decision, and its precious hours of opportunity are remorselessly ticking out. The zero hour for the final war of Amageddon is undelayably coming on" (The Commander to the Peoples, pp. 21-23). He continued by pointing to the United Nations plan drawn up in the Dumbarton Oaks Conference in 1944 and the 1945 San Francisco Conference as "the final total lineup of this old world against Jehovah's universal domination ... It is the time for the battle of Armageddon" (pp. 26-28).
So if Knorr actually predicted anything, it is this: The war would end with a peace treaty with the United Nations in charge of a global government orchestrated behind the scenes by the Vatican. The UN would be established very quickly through the placing of totalitarian armies around the world to keep the peace, and it would set to work immediately on banning Jehovah's Witnesses throughout the world. Then it would declare "Peace and safety!", the war is now over, but almost as quickly as the postwar period starts, the democratic powers discover that the Vatican is really running the show and they take action against the Pope and the Vatican, destroying the institution altogether. Then almost instantly, all the governments of the world undergo destruction themselves and billions of people are killed directly by God.
Now, I might not have the history quite right, but does anyone recall anything like this actually happening in 1945 and 1946?