Today's rally makes FTD almost impossible, which means a fast V shape bottom is very unlike, a W Shape is more like.

what is FTD:
Developed by William J. O'Neil, a Follow Through Day is an indication of a potential change of trend in place. After the market has made a new low and a rally has been attempted, a follow through day will be identified when a major index closes up 1.7% or more for the day with an increase in volume from the day before. A follow through day can only occur between four and seven days from a potential bottom.