Three years ago it was the second Friday in March, and all of the years before that it was on a Tuesday. We did all this crazy speculating on here on Tuesday, March 5th because we all were positive that's when we were going to find out based on analysis of prior years' data... and then we waited three painstaking days to actually hear.
So I think there's a good chance it'll be today, but there's no definitive rationale behind when notices go out. The good thing is, unlike EdLD interview notices, which went out staggered and kept me on my toes (to no relief!) for weeks, everyone hears about M.Ed. programs at the exact same time either way. So no news is literally just that - no news.