Fed chair announcement to come at 3 pm ET (1900 GMT)
President Donald Trump is widely expected to nominate Fed Governor Jerome Powell as the next Fed head from a list that includes current Fed Chair Janet Yellen, Stanford University economist John Taylor, former Fed Governor Kevin Warsh and White House economic adviser Gary Cohn. It's most likely Powell. It sounds like he's going to be the accidental Fed chair.
Powell has broadly supported Yellen’s monetary policy, and is seen as a more stock market-friendly candidate.
However, Part of me hopes Trump shocks the world and names Taylor or Warsh as his nominee. :)
A more-possible surprise is that he announces a vice-chair nominee as well. If it's Taylor (which he's hinted) that would be dollar-positive.
keep in mind:
Warsh< powell< taylor : bullish Yellen, Cohn : bearish