For once, the rumors were right.
Around lunchtime Tuesday, stocks began to slowly lift out of negative territory. This was right after Europe closed, and often when there is selling pressure in Europe (as there was at the time), our markets are weak. So no one paid too much attention to the fact that we started lifting right after Europe closed.
But by about 1 PM ET, as the market continued to lift, traders began discussing the idea that Janet Yellen's testimony might be much more dovish than was expected. The mainstream opinion was that she would placate Republicans and not go out of her way to emphasize that she would keep the bond program in place for as long as it took to convince her the economy was turning around.