Again, nothing on the macro front has changed: China is still slowing, Iran will still be pumping, supply is still expected to outpace demand, oil rig counts are growing, and shale is still producing. Tack on slowdown in driving, reductions in refinery demand, which has already been higher than normal due to higher than normal crack spreads, a US export swap w/ Mexico and very real eagerness to life the US embargo.
And...biggest of all no one can predict what they don't expect. I haven't seen a single forecast for the average oil price in 2015 lower than the current level. Hell, money managers are still net-long on NYMEX and options.
Good luck catching that falling knife, because it still has momentum to the downside.