Metman,
You raise a very good point. If I'm supervising at Heathrow, I have two choices. I can ring up Exeter to speak to the Aerdrome Forecaster who, through no failing of his or her own, has no local knowledge and usually gives me what's in the TAF, or the Heathrow Met Observer who has access to the same data, weather radars etc, and has the benefit of being a specialist.