I think the S&P is likely to see a wick down to around $2350 sometime in April, but will likely close the month green or pretty close to neutral.
If I am correct, then that should lead to a little more upside in the next 2 months on the way back up to the 50% retracement of the March plunge. Top should be around $2800 before rolling over again.
The 1.61 Extension of the March plunge just happens to correlate with the double top from 2000 and 2007. I'd say we have a decent chance of seeing $1450 in the S&P's future this year.
As for timing I drew a trend line down from the tops of the last 2 months. If we make it through April without a new low, then around Sept would be my best guess for bottom.
I would be looking to short the S&P from the 50% bounce down. Enter on a weekly or higher timeframe after testing $2792 and closing below.
Enter short $2750 (or as close to $2792 as possible)
TP 1 : $2045
TP 2 : $1750
TP 3 : $1475