What are the weather colour codes used by RAF pilots?

This is a pilot asking the pilot a question....I fly a Falcon 2000 for NetJets. When I land at RAF Northolt the ATIS (radio weather broadcast) uses a colour code to describe the weather. Can you explain what this colour code is please...It has mystified me and many of my fellow civilian trained pilots for years!

The RAF Air Traffic Controller's take the runway viability and the height of the lowest clouds above the airfield. Using the table below, they match viability and cloudbase and broadcast the appropriate colour as an indicator of the weather. RAF pilots are trained to instantly know what each colour implies...Blue being a fantastic day for flying and red being a day for drinking beer in the mess!

aviation color charter showing weather conditions