I've been looking at a bazillion different charts on SPY along with a cartload of other factors and my best good guess is a full on retraction coming next week.
Chartwise see how the candles on your chart were following above the 20,50,200dma up until last August and then again in January 2012 up until May of this year where as you have noted: it bounced off the 50dma.
I think the candles retest the 50ma bounce / break, if it breaks it, [which I definitely think it's going to do] then support around 120 / 115 if this area is broken then it could reach to bounce / break the 200dma around 110.
To the extent at which a correction will exacerbate itself is unsure, but there definitely is one setting up on the charts I've looked at, all of them.