I went hunting on google and found a formula for cloudbase;
Dry bulb - wet bulb x 125m
This would give a cloudbase on the day in question of 412' but the cloudbase was 2500'.
While it has been a VERY long time since I studied ATPL Met I have a strong recollection of using the method I used a few posts back. That it seems to give a closer to accurate answer, in this case, is interesting...but the formula espoused on the website I looked at exists too.
Just goes to show what a bag of worms predicting weather is
