Couple Of Questions From A Newbie

[Trancemaster1966]

Hello everyone.

Just joined Netweather a few weeks ago and only entered the forums this week. I have learnt quite a lot although a ton of stuff remains a mystery but I'll just take it a step at a time. I've been reading informative articles about the different types of cloud tonight, so thanks for those.

I digress. I've got two questions (both noob questions I'm afraid). I'm currently using a few different lightning detectors. I have tended to stick with the one at nowcast but the question is What is the record number of strikes recorded in the UK in one single 24 hour period? Secondly I've been boning up on humidity and now have a better understanding of what causes it. What I want to know though is why does it make a person feel so uncomfortable and start sweating? I know the vapour is in the air but why does it have that effect on us?

Cheers all. Hope someone can answer.

Grahame

[Bilz]

Hello everyone.

Just joined Netweather a few weeks ago and only entered the forums this week. I have learnt quite a lot although a ton of stuff remains a mystery but I'll just take it a step at a time. I've been reading informative articles about the different types of cloud tonight, so thanks for those.

I digress. I've got two questions (both noob questions I'm afraid). I'm currently using a few different lightning detectors. I have tended to stick with the one at nowcast but the question is What is the record number of strikes recorded in the UK in one single 24 hour period? Secondly I've been boning up on humidity and now have a better understanding of what causes it. What I want to know though is why does it make a person feel so uncomfortable and start sweating? I know the vapour is in the air but why does it have that effect on us?

Cheers all. Hope someone can answer.

Grahame

Relative humidity is defined as the ratio of water vapour content to the water vapour capacity of the air at a given temperature. When the realtive humidity is 100%, the air is 'holding' all the vapour that it can at a given temperature. Under these conditions the air is termed saturated, because no more vapour can evaporate into the air. Now, sweating produces cooling because the high velocity (high temperature) molecules have sufficient energy to break free from the surface and evaporate, causing the average speed of the remaining molecules to decrease, and these lower speeds correspond to lower temperatures. Hence in high humidity conidtions, sweat cannot evaporate and clings to ths skin and it feels warmer than it otherwise would in lower humidity conidtions.

[johnholmes]

hi and welcome to the forum and to Net weather

No idea about lightning detectors as never used one, well not hand held anyway.

Humidity, well that I may be able to help. Keeping it as simple as possible. We measure, at the same time, the dry bulb temperature and the wet bulb temperature. The dry bulb is the one we have all been so excited about in the past week or two. All the records are dry bulb temperatures. The wet bulb is just that, never mind the technical bit just now, its a thermometer bulb that is kept wet. Due to evaporative cooling it is ALWAYS lower than the dry bulb. The difference is the degree of humidity, more involved than that, but enough to be going on with. Using these two values we can work out something called the DEWPOINT, another definition=the temperature at which the air will start to show dew forming, again not the full definition but enough for now. using tables, if you are an old' un like me, or a computer now days one can then work such exotic items as vapour pressure, and relative humidity, relative to 0-100% that is. The higher the humidity, funnily enough the more humid the air is.

Why do we sweat, That is because a high temperature allows more water vapour to be present than if the temp was lower. Thus 80% humidity with a temp of 30C feels much much more unpleasant than the same humidity with a temp(dry bulb in each case) of, say, 10C.

The main reason why there is much much more rain in the Tropics than here, its due to the amount of water vapour 'hot' air can deal with compared to cold air. Another reason why rainfall in summer thunderstorms often, over a short time scale, will give much higher rainfall totals than a thunderstorm in Spring or Winter.

Got very complicated but hope that helps. If not ask again, and I or someone better at explaining will have another go.

regards

John

Edited July 28, 2006 by johnholmes

[Trancemaster1966]

Relative humidity is defined as the ratio of water vapour content to the water vapour capacity of the air at a given temperature. When the realtive humidity is 100%, the air is 'holding' all the vapour that it can at a given temperature. Under these conditions the air is termed saturated, because no more vapour can evaporate into the air. Now, sweating produces cooling because the high velocity (high temperature) molecules have sufficient energy to break free from the surface and evaporate, causing the average speed of the remaining molecules to decrease, and these lower speeds correspond to lower temperatures. Hence in high humidity conidtions, sweat cannot evaporate and clings to ths skin and it feels warmer than it otherwise would in lower humidity conidtions.

Thanks Bilz and John, top answers, cheers!!!

I always wondered why people were talking about Dewpoints in the forums John so thank you for that.

All explained very nicely. Blimey, this weather malarkey is more complicated than I thought.

Edited July 28, 2006 by Trancemaster1966

[johnholmes]

have a look in our Net weather Guides, also the Learners area, lots in both to help all with kinds of things. In no time at all you will be an expert!

John

[Trancemaster1966]

Thank you John, yes I have discovered the learner section and have been reading avidly....A lot of good articles by yourself I might add.

A bit too much to take everything in, in one night anyway....lol

[johnholmes]

many tks

just take your time.

The old adage, don't try to run before you can walk does apply.

Don't be afraid to ask, that is how we all learnt at some time.

I you want, feel free to pm I'm always happy to try and answer any weather questions. Sometimes I don't know the answer but I may know someone who I think does and can point you to the right place/person.

Its a wonderful subject, enjoy it.

John

Edited July 28, 2006 by johnholmes

[pottyprof]

many tks

just take your time.

The old adage, don't try to run before you can walk does apply.

Don't be afraid to ask, that is how we all learnt at some time.

I you want, feel free to pm I'm always happy to try and answer any weather questions. Sometimes I don't know the answer but I may know someone who I think does and can point you to the right place/person.

Its a wonderful subject, enjoy it.

John

didnt understand a word of it.. still sweating cobs..

thanks john for the explanation :lol: .. i think most of us love you.. HMMMMMMWHAAAAAAAAH

Edited July 29, 2006 by pottyprof