Have you noticed that certain Metars give further coded information after the QHN? Boscombe often does as well as Brize, Yeovilton and even Heathrow. This will only occur when there is a forecaster (as opposed to a trained observer) on the premises (as opposed to one at the Met Office at Exeter).
The information which is added indicates what the met-man reckons will happen in the next 2 hours. This information is very worthwhile as it will be right up to date, as opposed to the TAF which can be up to 6 hours old. Furthermore, the forecast is made by someone who has local knowledge. Beware of the trap that “No sig” means no change from the weather in the Metar and not “no significant weather” i.e. if the conditions outlined in the Metar are awful, it’s going to stay that way! Most of these “mini-forecasts” come from military units, but if you listen to their ATIS either by telephone or radio you’ll find they won’t give cloud base and visibility but use colour codes. If you don’t carry the appropriate explanation (there is one in Ops.) then a good aide memoir is as follows:
BLU Blue skies – conditions favourable for VFR.
WHI Cloudy conditions consider carefully if you want to fly.
GRN You’ll be very close to the fields; VFR very marginal.
AMB Don’t be a gambler.
YLW Be a coward; stay at home.
RED This is the colour of blood.
I hardly need mention this is a product of my imagination and not official!!