Gary said webmasters can expect it soon, soon as in the next two, to three, to four weeks. This will not necessarily be an algorithm update, where they change the signals of the Panda algorithm like we saw with 4.0 but rather Google just refreshing the underlining data of the algorithm. The difference between data and algorithm updates is somewhat explained over here.
So in the next few weeks you can expect us to cover this Panda update and yes, new sites will get hit, Panda victims may see recoveries or they may be worse off. We do not know, but when it comes out, it should be clear.
Again, the next Panda data refresh should be coming out within the next upcoming weeks according to Google’s Gary Illyes.