The % stocks above the 50ma is a very useful tool for signalling potential market turns. There are a number of ways to use it but one of the easiest is with the MACD of the % stocks above 50ma indicator. The chart shows that in every instance when the MACD gave a sell signal AND the indicator was making a lower high (marked with the red circles) a market decline/correction followed. When the indicator was making a new high sometimes a decline/correction followed (magenta circles) and sometimes it didn't (unmarked).
The current setup indicates a decline/correction is near at hand, unless the signal reverses.