These broadcasts are supervised by International Civil Aviation Organization (ICAO) in order to fulfill requirements of the ICAO Annex 3 covering meteorological information which is necessary for flights.
The role of the WAFCs is to provide meteorological messages with worldwide coverage for pilot briefing.
These are the UK Met Office and Washington NOAA, working in duplicate so it would be possible to replace each other in a case of failure.
Each of these two services operates its own satellite-based broadcast system to distribute data to airports all over the world.
The UK Met Office is called SADIS (SAtellite DIstribution System) and mainly covers Europe, Asia, Indian Ocean and Africa.