Basically it always comes down to supply and demand. There's probably no greater meaning or reason behind it other than that, and trying to pin one on it would just largely be pure speculation.
It most likely be. However, let me explain a hypothetical situation: A large exchange goes offline, BTC trading stops for a while. Algorithms are BTC starved and ready to pay a bit more per BTC. Since smaller exchanges 'follow' larger ones, this will quickly but temporarily spread resulting an overall high BTC price. Likely to happen?