On March 6, two days after the National Park Service issued their peak bloom date prediction, the Washington Post's Capital Weather Gang issued their own prediction of a peak bloom on April 9 (or, as they put it: "most likely between April 7 and April 11, centered on April 9".)
With March having been colder than they expected, they've now pushed back their prediction to April 13 (or, as they now put it: "between April 11 and April 15, centered on April 13").
You can find their discussion of the weather data that have gone into this revision, along with their proposals for what the probability ranges are, here.
And you can see photos of how the trees looked yesterday on the March 26 Cherry Blossom Watch Update.
Want to Help Support DC's Cherry Trees?
If you'd like to help support the care and upkeep of the cherry trees around the Tidal Basin, the Trust for The National Mall has launched an Endow a Cherry Tree Campaign. Donations go to the official Cherry Tree Endowment, which will give the National Park Service additional resources to fund the care, maintenance, and possible replacement of the cherry trees. You can find more information here.
The Trust is dedicated to marshaling private support for maintaining and improving the history National Mall area. I'm not affiliated with the Trust--just an admirer of their efforts.