Earlier this week, the Forex Blog speculated that the tide was turning on the Euro, which  had retreated from the $1.60 threshold. Sure enough, the month of April saw the best monthly performance by the Dollar in over two years. The sudden about-face by the Dollar stems from changes in interest rate expectations. Only a couple weeks ago, the consensus among investors was that the Fed would cut rates further at its next meeting; the only point of uncertainty was whether rates would be cut by 25 or 50 basis points.

As of today, however, there is only a 25% chance that the Fed will cut rates at all, if you go by futures prices. Regarding the Euro, investors are no longer so sure that the ECB will hike rates in response to surging inflation. In short, the new consensus is that the US/EU interest rate differential has stabilized. Then there is the economic picture; investors have "chosen" to be pleasantly surprised by the most recent economic data. While the economic downturn still seems inevitable, it may not be as severe as investors had previously feared. Reuters reports:

In contrast to slightly stronger U.S. data, the Ifo German business sentiment index this week showed the biggest monthly fall since September 2001.

Read More: Dollar heads for best month in 2-1/2 years