Seeing this interference on 40 meters. Seems to be on Holidays and weekends so would imagine it is being generated from one of the neighbor's houses when they are home. I do not notice it in the evenings.
I'm far from the expert but it looks to me like a really noisy switching power supply that is changing somewhat as components heat up. Or perhaps your neighbors have a plasma TV? I've heard those things are horrible.
Again... I'm totally guessing as I have lots of strange stuff too.
One reason for the guess is you say it is holidays and weekends so i suspect this device is something that gets turned on only when the neighbor is home.
In these scenarios it is one thing to identify it, it is a total other to remedy it. I am pretty sure my neighbors heat exchanger noisy as hell but I seriously doubt they'd do anything about it.