The registry of deeds is a tenant inside the Middlesex Superior Courthouse. When the courthouse closes, the registry closes. So on stormy winter days, the best way to learn whether the registry will be closed (or will have a delayed opening), is to use the public resources of the state's Trial Court system.
The Trial Court website which will be annotated with any court closing information relatively early in a storm - http://www.mass.gov/courts/
The Trial Court Closings account on Twitter, which is used to tweet-out news of closures - @macourtclosings;
The Trial Court recorded phone message line at 800/222-5178.
Of the three, I have found the Trial Court website to be the most reliably up-to-date.
Also, as soon as I have any news of closings or decisions that would otherwise affect our operations, I will put something on this blog and also on my own Twitter feed, which is