Background
We recently purchased a home built in mid-50s. At the time, no structural movement or displacement was noted by the home inspector. Over the last few weeks, there have been long cracks on the ceiling of a room appearing and worsening. We've had low temps averaging 40F (lowest 27F) and we keep the house 61F minimum at night.
The first crack that appeared was (A), then shortly after (C), and now (B) as of today. There is some evidence of previous repair (varying paint texture) for cracks (A) and (C), but not so much for (B). There are no cracks on the walls or elsewhere in the house.
Please see question after photos.
Approx locations from attic:
Ceiling:
Question
Is this symptomatic of a structural issue requiring a professional, or expected from an older home in low temperatures and remedied with DIY patching? If structural issue, what is the urgency (could it wait months)? Thank you!