So the happier of the two flashforwards, for the most part, seemed just a normal day in the life of the characters, with them waking up and beginning the day. This begs the question of why specifically have they flashed to this day and why are they showing such arbitrary things when there's obviously other stuff we'd like to see such as Maggie's kid or whoever the antagonist at this time is.

I think what will happen is over the course of this first half of the season, Ricks morning will continue, scene by scene, showing us just how Alexandria has developed and what else they've put together as a community. Well see other buildings they've erected and which of our group has managed to survive.

The day will progress until the mid season finale and at this point Rick will enter the cell Morgan built and low and behold the twist will be ya boy Negan locked up in there ala the comics. This obviously doesn't fit with the vengeance hungry rick we know at the moment which leads me to the crying flashforward.

Essentially, I think Rick is going to accidently kill Morgan whilst gunning for Negan in the mid season finale. To honour him the latter half will see Ricks perspective change and him long for his 'mercy to prevail over his wraith'.

Tldr; Rick will kill Morgan whilst trying to kill Negan mid season. The flashforward will then show Negan locked up as a direct consequence of this changing Ricks attitude.