My first guess would be that a nation has made some demands of the project that the project won't comply with, and that country has suggested they will seize the directory authority servers located inside it if the demands aren't met soon. [Edit: a new comment by arma on the original story, "To be sure to keep our source safe, we're not providing more details quite yet", makes this seem less likely.]
Or perhaps an insider has leaked some plans to the project.
Along another line of thought, if the US government wanted to further complicate online privacy, I imagine they'd choose a time like now, when headlines about the "cyber intrusions" of 2014 are at a peak. I wonder what other actors could have large enough power over their directory authority servers for the project to post this message.
Edit: Indeed, from a post below by paralelogram [0] and by checking https://atlas.torproject.org , it appears 4 of 9 are in the US. There are also two in Germany, one in the Netherlands (as well as another there that is only for bridge relays), one in Austria, and one in Sweden.