Google’s Gary Illyes(webmaster trends analyst for google) announced Panda refresh in upcoming weeks may be two or four weeks, as mentioned in one of the articles of search engine land by Barry Schwartz. This is data refresh and not the algorithmic change.
He mentioned that few sites will be affected by this data refresh, most probably the new sites will get hit by this data refresh. Those sites which are hit by this algorithm may expect some recovery if they have taken some correct steps. But not all the sites will recover.
Google Panda is well known to all, as this is an algorithm of google that works on the poor quality content. It was introduced in February 2011. When a website gets hit by google panda then the website has chances to recover on the next update.