In the target area discussions, I regularly read references to "true Gulf moisture" and the like. I understand the importance of moisture as a prime ingredient in severe convection (or any kind of moist convection), but I don't understand what sets moisture from the Gulf of Mexico apart from other brands. Isn't moisture, moisture? On a day with high Tds, does it really matter where the humidity originates? Why the distinction? Is it a matter of sheer scale? Does location have anything to do with it (i.e. I live in Michigan, which has an abundance of lakes, wetlands, and forests, versus the Great Plains, which probably aren't as efficient at generating their own moisture)?