Dont spread your own confusion onto the lad Jamie23
sorry mate but i don't agree & neither do any of the other instructors at the flight school, I seriously think you are misunderstanding what a TAF & METAR are.
I agree that in the trend section of a METAR the term from will indicate a change that may occur from a specific time however my understanding of the term FM in a TAF indicates a change from that time hence as the clock strikes 1800 the worst case scenario will be 3000m vis.