Tropical storm to reach Thailand by mid-week

[webfact]

Tropical storm to reach Thailand by mid-week

 

 

BANGKOK, 5th March 2018 (NNT) - The Department of Disaster Prevention and Mitigation (DDPM) has warned those living in the upper regions of Thailand of heavy rains from March 7th - 9th, due to a high pressure system moving in from China. 

DDPM Director-General Chayapol Thitisak, has instructed its regional offices to prepare for emergencies around the clock during this period. 

Heavy rain and strong winds have been forecast in upper parts of Thailand in the middle of the week, as a tropical storm arrives in the Northeast before moving towards the North, Central Plains and the East. 

Residents in these areas are advised to secure their homes and remain indoors during thunderstorms, as well as to watch out for broken branches and falling billboards. People have also been warned not to carry objects that can conduct electricity while outdoors, on account of the lighting.

 

-- nnt 2018-03-05

[PREM-R]

From OP "....heavy rains from March 7th - 9th, due to a high pressure system moving in from China. "

 

I always thought that high pressure brought settled, fine weather and it was low pressure that brought high winds and rain. 

[Wiggy]

2 minutes ago, PREM-R said:

From OP "....heavy rains from March 7th - 9th, due to a high pressure system moving in from China. "

 

I always thought that high pressure brought settled, fine weather and it was low pressure that brought high winds and rain. 

Correct. A storm is caused by low pressure.

[DM07]

Halt the rainmaking for a few days...it seems to work fine already!

Thanks for that!

[KhunBENQ]

1 hour ago, Wiggy said:

A storm is caused by low pressure.

I am not a meteorologist.

But storms are caused by pressure differences.

Wind from high to low pressure?

Edited March 5, 2018 by KhunBENQ

[KhunBENQ]

No question it is high pressure.

Differences look small to me (but what do I know).

And from experience: if Thai Met shows an 80% rain probability then there is really something in the making.

And look at the temperature differences. I am in the red zone

A hell lot of energy to flow!

Edited March 5, 2018 by KhunBENQ

[overherebc]

36 minutes ago, KhunBENQ said:

I am not a meteorologist.

But storms are caused by pressure differences.

Wind from high to low pressure?

All the heat in the atmosphere is carried by water vapour. Water vapour is less dense than air so a lot of it in the atmosphere causes a low pressure system.

If the air is very dry it obviously has higher pressure.

When the two systems meet the colder higher pressure system will slide under the warmer wetter less dense air mass pushing it upwards, as it rises it cools and can't hold as much water vapour so that condenses and falls as rain.

If there is a 'big' difference in the systems the wetter air will be pushed up faster speeding up the cooling and condensation rates so more and heavier rain will fall.

Local topography will have an effect as well. Winds blowing up and down mountains etc, anabatic and katabatic winds etc but that causes local variations only in the general pattern.

A high pressure air system is cooler in temperature but with much less vapour or cloud it allows more sunshine so you feel warmer from that rather than the air temperature.

Think about a clear sunny day in UK, in the sun you feel warm but in the shade it's cooler because the air is cooler and later in the year it gets chilly at night when the sun starts going down and the clear air allows the heat to radiate out with no vapour to absorb it.

Sometimes it can get more complicated.

Edited March 5, 2018 by overherebc

[bangrak]

'Water vapour is less dense than air...', erm, thank you professor, can I leave the room now?

[trainman34014]

I hope it rains until September and Bangkok floods for several months because they said floods like 2011 can never happen again as they spent 400 million Baht on a new wall as far North as N/Sawan, so lets see how good it is.

 

Anyone seen this wall out there that cost all that dosh ?

[overherebc]

30 minutes ago, bangrak said:

'Water vapour is less dense than air...', erm, thank you professor, can I leave the room now?

What does that mean?

[Reigntax]

46 minutes ago, bangrak said:

'Water vapour is less dense than air...', erm, thank you professor, can I leave the room now?

Yes, someone is about 600 times out.

[Reigntax]

19 minutes ago, overherebc said:

What does that mean?

 

It means you are incorrect. Unless we are talking about superheated dry steam which is highly unlikely unless produced under extreme pressures.

Edited March 5, 2018 by Reigntax

[overherebc]

1 minute ago, Reigntax said:

 

It means you are incorrect. 

So you are saying that water vapour is more dense than dry air?

[Reigntax]

5 minutes ago, overherebc said:

So you are saying that water vapour is more dense than dry air?

 

That is correct. Saturated air, even air at nominal ambient conditions has a mass mostly due to its moisture content. Then we could talk about density relationship to enthalpy but the variables are never ending

Edited March 5, 2018 by Reigntax

[overherebc]

1 minute ago, Reigntax said:

 

That is correct. Saturated air, even air at nominal ambient conditions has a mass mostly due to its moisture content.

Describe the last time you saw water vapour.

[Reigntax]

5 minutes ago, overherebc said:

Describe the last time you saw water vapour.

 

A cloud, a jet stream, a kettle boiling. Saturated water vapour.

A phase change from liquid to gas.

Edited March 5, 2018 by Reigntax

[overherebc]

16 minutes ago, Reigntax said:

 

A cloud, a jet stream, a kettle boiling. Saturated water vapour.

A phase change from liquid to gas.

A little bit wrong there, that's why I asked.

Clouds consist of water droplets not water vapour which is in fact invisible. I a kettle is boiling you will notice a clear section from the spout that then turns to water droplets as it cools slightly and the droplets form. It's the same in the atmosphere.

Your expression of saturated air comes from the relative humidity rule that states that relative humidity is expressed as a percentage of the amount of moisture present in the air relative to the the amount that air could hold at that temperature and pressure without condensation taking place or dew point in other words, when water droplets start to form.

Water vapour has the same physical properties as a gas and is less dense than air, that's why it rises and eventually becomes water droplets.

Edited March 5, 2018 by overherebc

[overherebc]

4 hours ago, PREM-R said:

From OP "....heavy rains from March 7th - 9th, due to a high pressure system moving in from China. "

 

I always thought that high pressure brought settled, fine weather and it was low pressure that brought high winds and rain. 

It does but first it has to shove the low pressure out of the way.

If there is a big difference in pressures it gets 'lively' with heavy rain etc but over a fairly short 2 or 3 days. If the pressure difference is quite small it generally takes longer with broken showers sunny periods etc over a longer time.

If the high pressure system is pushing in it can be short and severe. If the low pressure system is pushing in it can be more gentle but longer lasting, sun rain sun rain etc.

Edited March 5, 2018 by overherebc

[Cadbury]

4 hours ago, DM07 said:

Halt the rainmaking for a few days...it seems to work fine already!

Thanks for that!

No no! Get the planes aloft!

People in high places need to make money from the sale of the chemicals.

[overherebc]

2 hours ago, Reigntax said:

Yes, someone is about 600 times out.

If you're talking about about the density of water compared to air it's more like 714 times more dense.

Can't remember exact figures.

Edited March 5, 2018 by overherebc

[bangrak]

4 hours ago, overherebc said:

A little bit wrong there, that's why I asked.

Clouds consist of water droplets not water vapour which is in fact invisible. I a kettle is boiling you will notice a clear section from the spout that then turns to water droplets as it cools slightly and the droplets form. It's the same in the atmosphere.

Your expression of saturated air comes from the relative humidity rule that states that relative humidity is expressed as a percentage of the amount of moisture present in the air relative to the the amount that air could hold at that temperature and pressure without condensation taking place or dew point in other words, when water droplets start to form.

Water vapour has the same physical properties as a gas and is less dense than air, that's why it rises and eventually becomes water droplets.

Sorry for having started this, 'overherebc', but you came up with such a theory, which could have even irritated Mr Newton and his apple. Great stuff you wrote, but, but... Let me stick to basics, as I won't spend the evening debating about straight forward common sense things. It's just that some Thais with a good knowledge of English, and a taste for sciences, present on TV (really a few then?) might be getting it wrong because of you. OK, then let's go (but let the winds out of this a-b-c basic, and the influences of electricity):

- 'basic' air (the combination of gasses we breath, N and O, and the rest) is made of very light (specific weigh), and highly compressible molecules, while water (the tainted H2O in nature) consists of quite heavy molecules, and hardly compressible, pressure, yes, you get it already;

- in high(er) pressure zone, the air contains less to little water droplets (there is no such thing in nature as air without any moisture %), and is easier to compress (by natural forces), the higher the pressure the lesser water droplets in the air, so 'ascending' away from the surface;

- a low(er) pressure zone is an area where the air contains more to a lot of water droplets (100% 'moisture' is still not same though as being in compact water), the lower the pressure the more, and the harder to compress;

- 'light' (dry-er) air 'climbs' easy(ier) (partly because of its very low specific weigh);

- 'heavy' (wetter) air does raise to though, but with a structure change: look at fog f.i., myriads of very tiny droplets, so numerous the density, and the weigh, are so high this cloud formation hangs very close to the surface. At the other end of the scope there are the cyrrus, the highest clouds, containing a very light concentration, ...of the heaviest form of water (ice crystals). In between are all kinds of clouds, all also holding water, most from the evaporation of surface water, ...in different forms. The warmer these waters, the higher the quantity evaporating = going up in the air. Going up in the air, this moisture mixed with air is exposed to lower temperatures (well, not always, but...) which has the effect of condensating these water droplets, grouping them, and making them heavier, till at a point saturation occurs, where the weigh of drops becomes too high to stay in the air, ...and the drops fall down as raindrops, small or big, few or a lot (or snow or hail).

The mix of the previous, known to us as 'weather' is another chapter, I'm ready to pass through to you too 'overherebc', when you really want, but not today.

It was great teaching such things to (interested) pre-pubes and teens, where are the days?

Edited March 5, 2018 by bangrak

[HAKAPALITA]

If you cant do anything be a Teacher


Sent from my iPhone using Thaivisa Connect

[overherebc]

5 hours ago, bangrak said:

Sorry for having started this, 'overherebc', but you came up with such a theory, which could have even irritated Mr Newton and his apple. Great stuff you wrote, but, but... Let me stick to basics, as I won't spend the evening debating about straight forward common sense things. It's just that some Thais with a good knowledge of English, and a taste for sciences, present on TV (really a few then?) might be getting it wrong because of you. OK, then let's go (but let the winds out of this a-b-c basic, and the influences of electricity):

- 'basic' air (the combination of gasses we breath, N and O, and the rest) is made of very light (specific weigh), and highly compressible molecules, while water (the tainted H2O in nature) consists of quite heavy molecules, and hardly compressible, pressure, yes, you get it already;

- in high(er) pressure zone, the air contains less to little water droplets (there is no such thing in nature as air without any moisture %), and is easier to compress (by natural forces), the higher the pressure the lesser water droplets in the air, so 'ascending' away from the surface;

- a low(er) pressure zone is an area where the air contains more to a lot of water droplets (100% 'moisture' is still not same though as being in compact water), the lower the pressure the more, and the harder to compress;

- 'light' (dry-er) air 'climbs' easy(ier) (partly because of its very low specific weigh);

- 'heavy' (wetter) air does raise to though, but with a structure change: look at fog f.i., myriads of very tiny droplets, so numerous the density, and the weigh, are so high this cloud formation hangs very close to the surface. At the other end of the scope there are the cyrrus, the highest clouds, containing a very light concentration, ...of the heaviest form of water (ice crystals). In between are all kinds of clouds, all also holding water, most from the evaporation of surface water, ...in different forms. The warmer these waters, the higher the quantity evaporating = going up in the air. Going up in the air, this moisture mixed with air is exposed to lower temperatures (well, not always, but...) which has the effect of condensating these water droplets, grouping them, and making them heavier, till at a point saturation occurs, where the weigh of drops becomes too high to stay in the air, ...and the drops fall down as raindrops, small or big, few or a lot (or snow or hail).

The mix of the previous, known to us as 'weather' is another chapter, I'm ready to pass through to you too 'overherebc', when you really want, but not today.

It was great teaching such things to (interested) pre-pubes and teens, where are the days?

I would suggest you contact the met office at Bracknell.

Seems like they need your ideas.

Dry air about 1.3 g/L

Water vapour about 0.8 g/L

Forget about water droplets, they're not water vapour, and while I remember jet trails are more likely to be very small ice crystals rather than water droplets.

Edited March 5, 2018 by overherebc

[overherebc]

Water vapor.docxWater vapor.docx

6 hours ago, bangrak said:

Sorry for having started this, 'overherebc', but you came up with such a theory, which could have even irritated Mr Newton and his apple. Great stuff you wrote, but, but... Let me stick to basics, as I won't spend the evening debating about straight forward common sense things. It's just that some Thais with a good knowledge of English, and a taste for sciences, present on TV (really a few then?) might be getting it wrong because of you. OK, then let's go (but let the winds out of this a-b-c basic, and the influences of electricity):

- 'basic' air (the combination of gasses we breath, N and O, and the rest) is made of very light (specific weigh), and highly compressible molecules, while water (the tainted H2O in nature) consists of quite heavy molecules, and hardly compressible, pressure, yes, you get it already;

- in high(er) pressure zone, the air contains less to little water droplets (there is no such thing in nature as air without any moisture %), and is easier to compress (by natural forces), the higher the pressure the lesser water droplets in the air, so 'ascending' away from the surface;

- a low(er) pressure zone is an area where the air contains more to a lot of water droplets (100% 'moisture' is still not same though as being in compact water), the lower the pressure the more, and the harder to compress;

- 'light' (dry-er) air 'climbs' easy(ier) (partly because of its very low specific weigh);

- 'heavy' (wetter) air does raise to though, but with a structure change: look at fog f.i., myriads of very tiny droplets, so numerous the density, and the weigh, are so high this cloud formation hangs very close to the surface. At the other end of the scope there are the cyrrus, the highest clouds, containing a very light concentration, ...of the heaviest form of water (ice crystals). In between are all kinds of clouds, all also holding water, most from the evaporation of surface water, ...in different forms. The warmer these waters, the higher the quantity evaporating = going up in the air. Going up in the air, this moisture mixed with air is exposed to lower temperatures (well, not always, but...) which has the effect of condensating these water droplets, grouping them, and making them heavier, till at a point saturation occurs, where the weigh of drops becomes too high to stay in the air, ...and the drops fall down as raindrops, small or big, few or a lot (or snow or hail).

The mix of the previous, known to us as 'weather' is another chapter, I'm ready to pass through to you too 'overherebc', when you really want, but not today.

It was great teaching such things to (interested) pre-pubes and teens, where are the days?

Not much else to do this morning, the rain woke me up.

Just a couple of points.

Saturation point in the atmosphere is the point, combination of temperature, pressure and water vapour where water droplets form, not the point where they start to fall as rain. Look at any small white cloud in a clear sky and you'll notice that it's not just sitting there looking pretty. It is continually changing especially on the outer edges, the droplets are falling and if you watch long enough you'll notice the tend to disappear as they return to water vapour in the air around them. So it's an ongoing process and generally small clouds like that only last on average 10 to 15 minutes.

Once you get your head around the difference between water vapour and water droplets it might become clear.

When you talk about humidity and you hear 75 or 80% etc it doesn't mean that the air is 75 to 80% water. It means that the air is at 75 to 80% of the water vapour it could hold at that temperature and pressure without saturation point being reached, ie add 20 to 25% more water vapour at that temperature and pressure and water droplets will start to form. Cool that air as it rises, anabatic cooling, and it can hold less water vapour and droplets start to form making clouds.

 

Edited March 5, 2018 by overherebc

[overherebc]

6 hours ago, bangrak said:

Sorry for having started this, 'overherebc', but you came up with such a theory, which could have even irritated Mr Newton and his apple. Great stuff you wrote, but, but... Let me stick to basics, as I won't spend the evening debating about straight forward common sense things. It's just that some Thais with a good knowledge of English, and a taste for sciences, present on TV (really a few then?) might be getting it wrong because of you. OK, then let's go (but let the winds out of this a-b-c basic, and the influences of electricity):

- 'basic' air (the combination of gasses we breath, N and O, and the rest) is made of very light (specific weigh), and highly compressible molecules, while water (the tainted H2O in nature) consists of quite heavy molecules, and hardly compressible, pressure, yes, you get it already;

- in high(er) pressure zone, the air contains less to little water droplets (there is no such thing in nature as air without any moisture %), and is easier to compress (by natural forces), the higher the pressure the lesser water droplets in the air, so 'ascending' away from the surface;

- a low(er) pressure zone is an area where the air contains more to a lot of water droplets (100% 'moisture' is still not same though as being in compact water), the lower the pressure the more, and the harder to compress;

- 'light' (dry-er) air 'climbs' easy(ier) (partly because of its very low specific weigh);

- 'heavy' (wetter) air does raise to though, but with a structure change: look at fog f.i., myriads of very tiny droplets, so numerous the density, and the weigh, are so high this cloud formation hangs very close to the surface. At the other end of the scope there are the cyrrus, the highest clouds, containing a very light concentration, ...of the heaviest form of water (ice crystals). In between are all kinds of clouds, all also holding water, most from the evaporation of surface water, ...in different forms. The warmer these waters, the higher the quantity evaporating = going up in the air. Going up in the air, this moisture mixed with air is exposed to lower temperatures (well, not always, but...) which has the effect of condensating these water droplets, grouping them, and making them heavier, till at a point saturation occurs, where the weigh of drops becomes too high to stay in the air, ...and the drops fall down as raindrops, small or big, few or a lot (or snow or hail).

The mix of the previous, known to us as 'weather' is another chapter, I'm ready to pass through to you too 'overherebc', when you really want, but not today.

It was great teaching such things to (interested) pre-pubes and teens, where are the days?

Just thought I would add,

molecular weight of water vapour 18

molecular weight of oxygen and nitrogen 28 and 32.

You tell me which one is the least dense in the atmosphere.

[overherebc]

7 hours ago, bangrak said:

Sorry for having started this, 'overherebc', but you came up with such a theory, which could have even irritated Mr Newton and his apple. Great stuff you wrote, but, but... Let me stick to basics, as I won't spend the evening debating about straight forward common sense things. It's just that some Thais with a good knowledge of English, and a taste for sciences, present on TV (really a few then?) might be getting it wrong because of you. OK, then let's go (but let the winds out of this a-b-c basic, and the influences of electricity):

- 'basic' air (the combination of gasses we breath, N and O, and the rest) is made of very light (specific weigh), and highly compressible molecules, while water (the tainted H2O in nature) consists of quite heavy molecules, and hardly compressible, pressure, yes, you get it already;

- in high(er) pressure zone, the air contains less to little water droplets (there is no such thing in nature as air without any moisture %), and is easier to compress (by natural forces), the higher the pressure the lesser water droplets in the air, so 'ascending' away from the surface;

- a low(er) pressure zone is an area where the air contains more to a lot of water droplets (100% 'moisture' is still not same though as being in compact water), the lower the pressure the more, and the harder to compress;

- 'light' (dry-er) air 'climbs' easy(ier) (partly because of its very low specific weigh);

- 'heavy' (wetter) air does raise to though, but with a structure change: look at fog f.i., myriads of very tiny droplets, so numerous the density, and the weigh, are so high this cloud formation hangs very close to the surface. At the other end of the scope there are the cyrrus, the highest clouds, containing a very light concentration, ...of the heaviest form of water (ice crystals). In between are all kinds of clouds, all also holding water, most from the evaporation of surface water, ...in different forms. The warmer these waters, the higher the quantity evaporating = going up in the air. Going up in the air, this moisture mixed with air is exposed to lower temperatures (well, not always, but...) which has the effect of condensating these water droplets, grouping them, and making them heavier, till at a point saturation occurs, where the weigh of drops becomes too high to stay in the air, ...and the drops fall down as raindrops, small or big, few or a lot (or snow or hail).

The mix of the previous, known to us as 'weather' is another chapter, I'm ready to pass through to you too 'overherebc', when you really want, but not today.

It was great teaching such things to (interested) pre-pubes and teens, where are the days?

Here's a photo that might help you understand the difference between water vapour and water droplets.

Small cloud over a small lake. Sun heats the water surface and water vapour is produced, the water vapour being less dense than air rises until it reaches cooler air and becomes water droplets, ie the cloud. The water vapour is invisible because it's actually the gaseous form of water, that's why you can't see it in the photograph.

[overherebc]

1 hour ago, overherebc said:

Here's a photo that might help you understand the difference between water vapour and water droplets.

Small cloud over a small lake. Sun heats the water surface and water vapour is produced, the water vapour being less dense than air rises until it reaches cooler air and becomes water droplets, ie the cloud. The water vapour is invisible because it's actually the gaseous form of water, that's why you can't see it in the photograph.

Don't know where the photo went ?

[HAKAPALITA]

I find The TAT tourist arrivals like the Forecasts .Dreamer Predictions.Since our old Dog died im lost.[emoji240].On the Table,no Rain ,under it rained. Now i use this phone and its useless.


Sent from my iPhone using Thaivisa Connect

[overherebc]

10 hours ago, bangrak said:

Sorry for having started this, 'overherebc', but you came up with such a theory, which could have even irritated Mr Newton and his apple. Great stuff you wrote, but, but... Let me stick to basics, as I won't spend the evening debating about straight forward common sense things. It's just that some Thais with a good knowledge of English, and a taste for sciences, present on TV (really a few then?) might be getting it wrong because of you. OK, then let's go (but let the winds out of this a-b-c basic, and the influences of electricity):

- 'basic' air (the combination of gasses we breath, N and O, and the rest) is made of very light (specific weigh), and highly compressible molecules, while water (the tainted H2O in nature) consists of quite heavy molecules, and hardly compressible, pressure, yes, you get it already;

- in high(er) pressure zone, the air contains less to little water droplets (there is no such thing in nature as air without any moisture %), and is easier to compress (by natural forces), the higher the pressure the lesser water droplets in the air, so 'ascending' away from the surface;

- a low(er) pressure zone is an area where the air contains more to a lot of water droplets (100% 'moisture' is still not same though as being in compact water), the lower the pressure the more, and the harder to compress;

- 'light' (dry-er) air 'climbs' easy(ier) (partly because of its very low specific weigh);

- 'heavy' (wetter) air does raise to though, but with a structure change: look at fog f.i., myriads of very tiny droplets, so numerous the density, and the weigh, are so high this cloud formation hangs very close to the surface. At the other end of the scope there are the cyrrus, the highest clouds, containing a very light concentration, ...of the heaviest form of water (ice crystals). In between are all kinds of clouds, all also holding water, most from the evaporation of surface water, ...in different forms. The warmer these waters, the higher the quantity evaporating = going up in the air. Going up in the air, this moisture mixed with air is exposed to lower temperatures (well, not always, but...) which has the effect of condensating these water droplets, grouping them, and making them heavier, till at a point saturation occurs, where the weigh of drops becomes too high to stay in the air, ...and the drops fall down as raindrops, small or big, few or a lot (or snow or hail).

The mix of the previous, known to us as 'weather' is another chapter, I'm ready to pass through to you too 'overherebc', when you really want, but not today.

It was great teaching such things to (interested) pre-pubes and teens, where are the days?

Drier air doesn't tend to rise. Because it's drier there are fewer water vapour molecules mixed up with it. Water vapour being mixed with it means in any parcel of air will become less dense as water vapour increases or more dense as water vapour decreases.

That's why atmospheric pressure drops and the area becomes known as low pressure area. The adjoining air mass next to it with less water vapour in becomes more dense so it's called a high pressure area. The edge where they meet is call a front and that frontal area produces what is called weather good or bad depending on what you're looking for.

In the case at the moment the high pressure area will push under the warmer area causing it to rise quite quickly condensing the water vapour and causing the rain.

Edited March 6, 2018 by overherebc

[RichardColeman]

Wish it would hit Pattaya, it needs a good clean and rinse.