When did fog become . .

[Rowana]

. . very poor visibility?

Up at the boat yesterday and it was a wee bit foggy.

On the shipping forecast, the vis was given as "Poor or very poor". I always thought that "poor" was defined as 1000metres to 2 miles, and less than 1000metres was defined as fog.

When did this change, and why?

I must admit that it is the first time I've heard "Very poor"

 

[FWB]

See visibility definitions on this page Met Office

 

[duncan]

Very poor Less than 1 km
Poor Between 1-4 km
Moderate Between 4-10 km
Good Between 10-20 km
Very good Between 20-40 km
Excellent More than 40 km

 

[Rowana]

Thanks Duncan & Dylan, I know that is the present definitions, but I always thought that less than 1000meters was defined as "Fog"

What I really want to know is, when did it change, and why.

 

[FullCircle]

Dover Coastguard giving out Visibility warnings yesterday-------

Vis at XYZ bouy 1 cable
Viz at ABC buoy 2 cables
Viz at Dover Harbour errrrr.... 1 km.

Now how does that work?

 

[RobBrown]

Coo- just done my CS/YM theory and that was still in miles, except for fog- <1000m! /forums/images/graemlins/confused.gif

 

[FWB]

Fog is fog, Just like Snow is snow and Rain is rain. Visibility is how far you can see.