There is a lot of information about Episode 1 from the promos. We know that all of the main characters are in Tar Valon at the start of the season.
Major events in Episode 1:
The Black Ajah's escape (confirmed by Rafe).
Moiraine and Siuan reconnecting (unconfirmed but certain).
Egwene’s Accepted Test (confirmed by metadata).
These are the events that need to happen in Tar Valon and may be the key reason for starting the season there.
Other likely events in Episode 1:
Bubble of Evil (It happens in Tar Valon, but could be in Episode 2).
Lanfear visiting Rand (speculation).
The season starts with Siuan confronting Liandrin as a Darkfriend in the presence of Nynaeve. I think, prior to this, all three girls, along with Moiraine, had convinced Siuan that Liandrin is a Darkfriend. This could be why she allowed Rand to stay in Tar Valon, despite what happened in S2E7. Moiraine will almost certainly join the Black Ajah fight, given that we see her five minutes into the fifteen-minute-long confrontation scene. She could reach Siuan by the end of this scene, and their interaction will be the first scene after that long cold open. In their conversation, they could set up the need to get out and go to the Aiel Waste, ponder on the Black Ajah and forsaken, and address the need to promote Egwene.
Does anyone have different ideas?