I'll explain why.
If history is any guide for the future, then the pattern that we saw in the period of AUG 24-SEP 29 could pop up again, a wave iv. That time, it lasted 25 bars/36 calendar days. (The bigger picture is a corrective pattern since May 2015 (wave IV)).
This minor wave iv and v pattern may also take 25 trading days, or roughly 35 calendar days, to play out. So that would indicate FEB18-22. The Russell 2000 confirms this scenario, click here http://tripstrading.com/2016/01/16/us-markets-russell2000-and-sp500/
Support was tested last Friday (orange) and closed well above 1857. So use that level as stop loss for now.
Target is the 1940-60 area for wave iv up. Target for wave v down is 1850 --> A = C = Red Support Line.
Please keep in mind that the markets don't always do as I would like them to. So think for yourself and never follow someone blindly.