I did some analysis of close at 20 day high vs close at 20 day low and found some interesting things. First bottoms are generally indicated by high numbers of 20 day lows vs low numbers of 20 day highs. And, conversely, tops are suggested by the opposite configuration. Which makes sense. When the market hits extremes in either direction it reverses.
What I saw is that after several days of high numbers for either axis (i.e. anything in excess of 500) the market starts going in the other direction. It doesn't generally happen overnight because I think it takes a little while for the trading community at large to catch on to the "new" fact of the market. What is the "new" fact of the market? When there are lots of stocks hitting an intermediate bottom, i.e. the 20-day low, then there are lots of buying opportunities. Obviously the more buying opportunities there are the more buying that will take place and vice versa.
The last 4 days have seen 594, 584, 380 and 836 20-day highs respectively. That would suggest that there are lots of stocks ready to be sold. It wouldn't surprise me at all to see a market decline next week.