Re: Anyone who uses a Guitar Case Humidifier?
Sorry I missed this.
Yes, I would attribute this to humidity. Its those large swings that do the damage and throw everything out of whack. You've gone from swollen and wet to shrunken and dry, but the area where the scarf joint is stays pretty much the same. This movement is retained in the woods memory, and results in the hump.
Try this experiment to help you grasp what is going on.
Take a section of newspaper, wet it thoroughly and then loosely fold it around an object or roll it up, then allow it to dry. After it has completely dried, unfold the paper and see if you can get it to lay perfectly flat. Any luck? Didn't think so.
This can be thought of as the state your neck is in that causes the hump. The paper has hardened and is trained into whatever shape it was dried in. To get the paper to lay flat again we have to re wet it and let it dry flat.
This same principle is applied to your guitar, only on a much more complex and subtle scale. And getting a guitar neck (or top or whatever) to lay flat again is much harder than the newspaper, which is why its important to just maintain the correct level in the first place.
That being said, after I repaired your neck I seriously doubt that it will ever get as bad as it was no matter how you much you may neglect it, but you need to stay on top of it to optimize the instrument to its full potential.
Its good you caught it early and that you are stabilizing it. Keep it in the case most the time and at 45% and you should be fine.