Dean and Rose:
As you guys know, the energy spreads have their own unique set of idiosyncracies 'and local knowledge' kind of nuances to them. I mean, the floor locals and OTC brokers even quote them different than the interest rate and ag brokers do.
I am going to throw out a 'general tendancy' for many calendar spreads in 'normally' or 'traditionally' shaped curve environments (which we are not in): As a flat price front month market sells off, you will usually see some firming up of the front month calendar spread. True for the bond spread and true for the oil spread under typical 'backwardation' conditions which reflects the carry yield premiums.
The interest rate yield curve is batty and the crude oil curve is batty, so I have seen that tendancy be much less common than it used to be whn oil traded between $30 and $50/bbl. for years on end. Look at the oil curves for the past three years after the market sold off from historically high levels.