Failure
This failure was nearly identical to my last one so instead of spending a lot of time on analysing it I think I'll go meta and get straight into figuring out why my previous attempt to fix the same problem didn't work.
Part of it was that it takes some time to set up a new habit, and trying to write in the morning to avoid these kinds of failues hadn't quite taken yet. But, looking at my plan from last time, it was also lacking in specificity. I weaseled a bit with "I should be aware of" the tendency to fail on weekends (although this time it wasn't a weekend, it was pretty similar), and "aiming" to write in the morning "may be the solution".
So I'm not going to make any changes to my overall strategy, but I will clarify the particular tactic I want to use to get there. I'm going to set myself a motte and bailey goal. The motte is that I intend to write each post by the start of the 24-hour posting window. The bailey is that I must write it by the end. As I said, effectively the same as my current plan but better specified.
Wish me luck!