Rapid change in visibility
 

Saturday 7th August saw me plodding from Surrey up to Leeds.

Viz as far as Leicester or thereabouts was pretty much unlimited, but as we approached there, we could see a wall of haze - it's the only way I could define it. It stretched from east to west, curving towards the north the further west it went.

Once in the haze, the viz dropped to about 6 - 8 miles or so. The temperature didn't change, according to the thermometer in the aircraft.

Wind was southerly about 15 knots - we were cruising at about 3000' or so.

Any ideas ? I've never seen anything like it.