Just after posting this thought, the Euro pulled back relatively sharply off the resistance levels I noted. The US dollar bounced as well. At the same time, the market pulled back sharply, as you'd expect, before floating back up for the rest of the day.
|FXE (candles) with SPY overlayed (line)|
Tonight I'll be watching the Euro and US dollar futures. If the Euro fall/USD bounce continues, the market will have a difficult time pushing up under any kind of heavy volume.