weatherhobbit wrote:
On Nov 9, 9:31 pm, Joe Egginton wrote:
snip
So is freezing fog super cooled water droplets that turned into ice upon
contact of an object in the sub zero air?

... yes, that's the basic physics of what is going on. The final
product is rime ice, and in suitable conditions, it can build up
dramatically - essentially the same thing that aircraft encounter when
they fly through clouds of *very small* droplets, with weak updraughts
supporting the cloud development - stronger updraughts tend to larger
droplets and harder, clear or near-clear ice.

However, as Will points out, it is perfectly possible for NO rime to
form even though the air temperature is (usually just) below freezing:
the complex temperature changes / latent heat exchanges may mean that
the temperature of a particular object doesn't reflect the 'screen'
temperature - which is of course a rather artificial environment. I've
experienced several instances of this where surfaces remain wet for
some time.

Rime ice gives rise to some stunning pictures when the sun comes out!

Martin.

--

Thanks for your reply Martin.

What would be recorded, if the scenario was:

Air Temp: -1c
Dew Point Temp: -0.5c

There's rime on a metal post, but no rime on a wooden fence. Would that
be recorded as freezing fog?

Joe
Wolverhampton
175m asl