As you can read from the article below, Radio 1 will be launching an official midweek chart show on a Wednesday. The show is only half an hour in length but will include a countdown of the top 40 singles as well as albums.
This is introduced just in time so that the week of the 15th we will be able to see where Sweet 7 is going to chart according to the mid-weeks on the Wednesday before the actual position is revealed on the Sunday, meaning fans can then act accordingly, promoting the album more or buying it in an attempt to get an even higher chart position.
http://www.dailymail.co.uk/news/article-1255597/Radio-1-introduce-midweek-pop-chart-following-Joe-McElderrys-Christmas-single-battle.html