You mean like yesterday, when if you pressed all the right buttons you'd have found that the cloud at Bournemouth was going to be scattered at 3500', and the actual weather was Cavok? So you went flying, and when you came back half an hour later it was broken at 300'?
That does happen, because forecasting is very imprecise much of the time, especially when it comes to transient / coastal fog/haze conditions, but anybody who thinks they can become amateur weathermen, and beat the people who get paid to do this all day long, with any statistical significance, are kidding themselves.
I know it is tempting to try to understand weather, but it doesn't work. For starters you can't get your hands on the data. The minimum package from the UKMO is a few grand a year,
AFAIK. Most of the commercial weather packagers make heavy use of the free US-run GFS model but it isn't any good for small scale effects like coastal fog popping up.
What might help is using the satellite imagery. I use
this for a "cloud tops METAR" (and it is excellent) and you could use
this to see stuff like fog building up offshore.
in an inversion there is a temperature increase with altitude.
Indeed; I went for a flight to FL100 a couple of days ago and the SFC temp was about 0C and at FL100 it was +6C. That is one helluva inversion...