In reply to Jamie Hageman:
> I imagine the temperature inversion was still in effect, it's just there was little or no cloud forming to show it visually.
Exactly.
We've had such an unseasonably dry time - and that's set to continue for another two weeks at least - that I imagine it's hitting cloud formation in the valleys, so whilst there are lots of inversion layers there's no cloud pinned under them.
You can still tell that there's an inversion layer present in various ways - often by the stench of trapped diesel fumes filling the air in valley bottom villages, and from the way smoke from a chimney or grouse moor burn will rise a short distance and then go horizontal. Watching a couple of bonfires this evening, the smoke would rise a few meters then cling to the ground for half a km.
I don't recall a January like this - sometimes we get a few glorious weeks in spring with the kind of dry, blocking high. 1040 mb sea level pressure here today, near as damned it.
Post edited at 21:19