In the latest issue of Famitsu, Atlus has taken a two-page ad out that hints at an announcement on August 1st. According to a quick translation from the folks at NeoGAF, the tag reads:
On the day when Yin and Yang come together a new jiken (event/incident) will begin.
Seems like this is another Raidou Kuzunoha game. Any other guesses?