S&P500 is reversing higher in a very strong and impulsive manner from the lows, so it appears that wave 4 can be deeper and more complex as we see current rise still as wave A) that belongs to a three-wave recovery so more upside should be coming after wave B) pullback. 

Short-term support is at 2660/80 area from where bounce may occur this week for a rise towards 2821.

S&P500, 4h