<Northwestern notifies by letter and a change on your application status page which will first say that a decision has been made. The letter will probably come first before the status page says that you are accepted.>
Yeah, Northwestern will update your status page and say that a decision has been made on your application and you should expect to receive a letter soon. Then the letter will come right around that time. For me, my status page was updated about four days before I received the letter via snailmail. But their next round of decisions won't occur until the end of February if I am not mistaken. I could be wrong but that is what I remember from my interview day back in October. Good luck.