I should have put more of the passage there.
(Matthew 24:29-31) “Immediately after the tribulation of those days, the sun will be darkened, and the moon will not give its light, and the stars will fall from heaven, and the powers of the heavens will be shaken. 30 Then the sign of the Son of man will appear in heaven, and all the tribes of the earth will beat themselves in grief, and they will see the Son of man coming on the clouds of heaven with power and great glory. 31 And he will send out his angels with a great trumpet sound, and they will gather his chosen ones together from the four winds, from one extremity of the heavens to their other extremity."
So, the tribulation does not culminate in Armageddon, according to Jesus. Right AFTER the tribulation, is when signs in heaven will be and when the "second coming" occurs.
It's possible that Armageddon comes after that. It's also possible that what WT refers to as the final test at the end of the 1000 years in Rev 20:8 is actually what Armageddon refers to. I'm not so certain about that, but it's something that some feel could be the case.