Everybody is gearing up for Fed day. There will likely be volatility and an overreaction to the decision. Even if the Street gets what it wants, a positive price move will likely be short lived. As Rob at Quantifiable Edges points out, positive reactons to the fed tend to fade over the following two weeks.
Technicals also do not lend themselves to a sustained upside move. The market is overbought (see stochastic levels) and price has made a strong "v" move right into resistance. The market needs a pullback before making a big move higher.