FOMC announcement very soon. How will the markets react?

As they tend to do, markets will likely react in dramatic and jolting fashion upon the FOMC's policy statement release before regaining their composure, assuming predictions of QE4 are correct. Stocks and commodities should shoot up briefly, as should commodity-based currencies, such as the Canadian, Australian, and New Zealand dollars against the U.S. dollar.

Another possibility is that traders have already priced in QE4, having already bought the rumor, and are now waiting to sell the news. 

If the Fed announces no action, the bears should takeover.