Jon's weather blog

Ay up!

As I write this it is still cloudy outside my window here in Leeds.

A glance at the satellite picture tells me that most parts of the ITV Yorkshire region are basking in sunshine.

Maybe I have upset somebody because there is just one patch of cloud that is stubbornly sitting over West Yorkshire.

There is an old weather saying:

‘Evening red, morning grey,

Are two signs

Of a lovely day’

Most of us started under cloudy skies this morning with mist and patchy fog.

The sun has eroded this away so that only the patch I’m sitting under remains. There is time yet though and even in West Yorkshire I think it will get out this afternoon as the sun continues to evaporate the cloud droplets resulting in blue skies.

It takes a tremendous amount of energy to evaporate water from its liquid form (cloud droplets) into its gaseous form (invisible water vapour)

Imagine you are at the beach on holiday. Despite a breeze, it’s unbearably hot! It’s no good; you cannot stand it anymore, it’s off to the sea for a dip.

When you come out dripping wet, and stand on the beach in the breeze you feel quite chilly all of a sudden. Why is that?

The reason is the sea water droplets on your body are being evaporated into water vapour. As I said, it takes a lot of energy to complete this process and that energy it taken from your body in the form of heat. Consequently you feel cold. Until all the water has evaporated you won’t start to feel warm again.

Once the sun sets this evening the gaseous and invisible water vapour will start to condense back into cloud overnight tonight and the process will repeat itself again tomorrow, and quite likely again on Sunday.

I’m off out for a lunchtime stroll now to see how the sun is performing in the cloud evaporation process. Oh and I may buy a sandwich as well.

Cheers for now.

Jon Mitchell