Only twice in the last 11 years (2000 & 2007) have all of my directional weekly moving averages turned down into a negative crossing, which subsequently confirmed that an acute, intermediate-term bear phase was underway.
In 2000, after the downside moving average inflection point, the S&P 500 declined from 1380 to 768 (-45%), and in 2007 the SPX declined from 1475 to 666.79 (-55%).
Looking at the weekly chart of the SPX, let's notice that all of my intermediate-term directional moving averages are pointed down, which in and of itself argues strongly that the dominant trend direction is down, with the "fast" 13-week MA having crossed beneath the declining 26- and 52-week MAs early in August.
The 26-week MA also is pointed sharply to the downside, but has not crossed beneath the 52 week MA. That said, any net weakness next week will assure such a downside crossing, thereby triggering a completed negative weekly moving average sell signal -- the third such signal since 2000.
This is an apparent pre-condition for a potentially very powerful decline -- or, in the current case, downside continuation towards optimal target zones at around 1000, and possibly 800 thereafter.