You're basically trading expiry roll. So there's not much of TA to do with that. Up until about 2 or 3 days before expiration of the front month it's about interest rate and dividend... the last days are about the roll-over.
It depends a lot on who's got what and how are they exposed...
PS. You do realize that the chart you posted isn't really valid anymore from the 15th right? Because that's when your Sept future expired and the swing after that is basically the full Dec future on it's own.