While no one involved in the equity markets needs to be reminded that the market is weak, it can be helpful to explore some measures surrounding this decline.

Brett Steenbarger at TraderFeed looks at what happens to market after an "intermediate period of weakness"? In the short term the market tends to continue falling, but over the forthcoming 20 day period the market tends to bounce back.

TraderMike looks at the historical record of a popular measure (% of stocks above their 40 day moving average) and an update. The measure after bottoming a week ago or so, is once again approaching the lows. In the qualitative camp, Mike notes the "whooshy" feel of the market.

Eddy Elfenbein at Crossing Wall Street notes the S&P 500 has given up all its gains for the year.

Barry Ritholtz points out that the VIX, that is volatility, has reached a level not seen since 2003. Then again, if the market keeps falling we can always blame Alan Greenspan!

One should respect the trend, which is clearly down. However keep an eye out for observations, like those above, that may indicate a pause in the selling. Be careful out there.