Get ready for the 'return of volatility' (SPY, SPX, DJI, IXIC, XWD, IWIM)

With Labor Day behind us and summer unofficially over, markets should get busy again.
"I think September and October could live up to their reputation for the return of volatility in the markets," Jeff Kleintop, chief global investment strategist at Charles Schwab, told Business Insider on Friday.
"I wouldn't be surprised to see a correction take place again. It's been a while," Kleintop said. "We're probably due for a little bit of a pullback."
Volatility could fling stocks either upward or dow