The doctrine of imminency refers to an event that is, so to speak, “hanging overhead; it is something that is ready to occur or could occur at any moment.” Now note, other things may happen before the imminent event, but nothing else must occur before happens. If something else must occur first, then that event is not imminent. Further, no specific amount of time is known regarding when the event will happen. It may be soon or it may not be. If a certain amount of time were needed before the happening of the event, then it would not be imminent. So an imminent event, like the return of Christ for the church, could happen soon, or it might not, but it could.
However, there are signs that clearly precede certain other prophetic events like those that will occur in the period known as Daniel’s seventieth week, like the return of the Jews to Palestine, for instance. These are not signs, however, that are necessary for the rapture. They simply suggest things are rapidly moving forward toward the end time conditions as described in many passages of Scripture. If, as I believe it does, the rapture precedes this, then that simply suggests that the Lord’s return for the church is sooner rather than later, but that in no way effects the concept of imminency. I do believe that once the church is caught up and removed that the other prophetic events will most likely move forward at a much faster pace.
The prophetic clock deals with these other events, not the rapture that could be setting the stage for the Tribulation. They pose a warning for those who have ears to hear of the need to turn to Christ that such days might not come upon them as a thief. Christians, by contrast, are to be ever mindful of the hope of Christ’s any moment coming and live circumspectly in the light of that truth as people of the light and the day.
I think this is part of Paul’s point in 1 Thessalonians 5:1f. As a result, the exhortations found in many passages like Titus 2:13 (see also 1 Cor. 1:7; Phil. 3:20; 1 Thess. 1:10; Jam. 5:7, 9; 1 Pet. 1:13; Jude 21) would lose their significance if the church had to go through certain conditions as described in the Tribulation. Then they would be looking for signs and a number of successive events (the Antichrist, the two witnesses, and much more) rather than the coming of the Lord. By contrast, the Tribulation saints are told, in essence, to look for and expect certain events before the Lord comes.