The Lingering Fog

[Lauren]

I know why fog forms, but what's the reason for it lingering pretty much all day for the last week or so?

[Terminal Moraine]

I know why fog forms, but what's the reason for it lingering pretty much all day for the last week or so?

In a nutshell, persistently mild weather with high dewpoints and a lack of air movement.

Normally in November you would expect a succession of Atlantic lows with ridges of high pressure between them bringing brisk winds and turbulent air from the west.

This November we've seen a persistent blocking high to the east and north east of Britain and low pressure held to the west. This has brought mild, humid air from the south or south east on many days with generally light winds and no activity to move things along.

And if you think it's foggy where you are try living up here, well over 200 hours of fog so far this month.

[4wd]

I'm not sure all that Atlantic hurly-burly is 'the norm' for November as it's a notoriously foggy month.

Mainly there just isn't enough power in the sun to make much difference to daytime temperatures now, so the only mechanism to shift it is wind blowing in less saturated air and/or stirring up inversions.

[Bottesford]

Warm air holding a lot of moisture cools at night then out pops the fog...

Come morning the sun has insufficient power to evaporate it - with the fog itself reflecting sunlight meaning it can only burn away at it from the edges by being able to heat the ground around it thus warming the air above it. That's my take on it!

[Lauren]

Thanks for your answers.

So as i understand it, the fog is formed by the warmer air mositure cooling . Usually the sun and wind would break through this in the morning, but due to a lack of sun and wind, it remains.

[lorenzo]

http://theweatherprediction.com/fog/

Haby Hints has a few articles on Fog - Enjoy !

[johnholmes]

I know why fog forms, but what's the reason for it lingering pretty much all day for the last week or so?

hi Lauren

couple of things why it lasts.

Time of the year=less daylight, its still dark at 0700BST, several weeks ago it had been light a couple of hours, so the radiation process may still be occurring

less actual radiatiative heat from the sun due to it being low down.

shorter days so the 'heat' from the sun needed to clear it, disappears earlier in the day

Specific for the last few days was lack of breeze that helps stir the bottom several hundred feet.

I've probably missed something but the ones I've mentioned are probably the main causes of it lingering.