New METAR comes to tower. Gives weather as 'Nil' but it's peeing down outside having started just before the ob time. When I query this they say 'ah but it hasn't rained for 10 minutes yet'.
Neighbouring airfield (with met observer but no forecaster) reports they are 500m in fog. I tell met; forecaster says 'they must be wrong, I haven't forecast any fog within 25 nm'.