Reviewing the chart, I'm looking for a channel or trendline kissback of some sort, the rejection of which would send us into a proper wave 3 selloff. The 50% retrace of this 2-day decline is around SPX 1870, which is the lower edge of the old channel, right about the time of the FOMC notes release on Wednesday. If the meeting notes suggest strong support of the end of QE, and/or regret for having pursued it in the first place, we will roll over and continue the decline, piercing the 1800 level.
The bottom for this first leg should then be around 4/16, before April opex, and after the April Full Moon. This would give us plenty of time to rally back for the next Bradley turn date due at the end of the month -- right before the next FOMC.