trust me. i know it is frustrating to just sit and wait for that acceptance letter, especially if maryland is where you want to go. however, even though admissions may have indicated that they would notify everyone at once, they also stressed just as much, if not more, that they did not want to be bombarded with calls asking about their status and stressed the virtue of being patient. their interview timeline may have been thrown off by the weather, but whatever the reason that they sent some acceptances out early, i'd advise you to refrain from calling their offices just to ask why some people received letters and others have not and then point out to them that they told you they weren't going to do rolling admissions. because bottom line, persistance may work in your favor to a point but you should still remember that they are busy with a lot of other things, especially since they're still conducting interviews.