Blizzard has announced that Heart of Fear (normal mode) will open next week but it will be another two weeks for Terrace:
To help raiders prepare their schedules for next week, we wanted to give everyone a brief heads-up that the Normal mode Heart of Fear will be debuting alone on Tuesday, and the Normal mode Terrace of Endless Spring will now open two weeks following the release of Normal Heart of Fear.
To help players focus on tackling these new encounters without feeling overwhelmed, we’ve decided to stagger the release of the two remaining raid zones. Heart of Fear should prove to be a challenging zone that will take the typical group some time to master, and players must defeat the Grand Empress Shek’zeer at the end of Heart of Fear before they may move on to Terrace of Endless Spring once that zone unlocks.
The unlock schedule for Looking For Raid modes for Heart of Fear and Terrace of Endless Spring is unaffected by this change. Heroic Heart of Fear will still be accessible to players who have cleared the zone on Normal difficulty. source