What is the cause of cold fronts?

[seriously disabled]

What is the cause of the cold fronts which dominate Alberta, Saskatchewan and Manitoba and also the northern United States like Massachusetts and Michigan during winter?

[D H]

Cold land masses.

 

Uri, what game are you up to? You have been asking basically the same question over and over at this site and elsewhere for quite some time now. There aren't any bona fide meteorologists at this site or at the other places who can give you a detailed and accurate answer to your questions. There is a much better place than a site such as this where you can find the answer to these questions. Here is a picture:

 

[CaptainPanic]

It seems to me that the girl in the picture knows more about the bad weather? Generalizing, girls are therefore the cause of bad weather?

 

I knew it! I knew it!

 

More serious: a library is indeed a place where you can find books. Meteorology is a field which is surely described in a nice book. You can also pick it up in the geography lessons at school.

 

A cold front is a weather transition where cold air is pushing into warmer air. These are simply caused by cold air moving into warm air. And air is moving around because of pressure differences.

Read more: http://en.wikipedia.org/wiki/Cold_front

[morganparkar]

Hi,

A cold front contains air that is cold and heavy.Warm air is lighter (that is why hot air balloons go up).When warm air meets cold air the cold air acts as a barrier and forces the cold air to go up. The hot air cools down as it gets higher.

[seriously disabled]

It seems to me that the girl in the picture knows more about the bad weather? Generalizing, girls are therefore the cause of bad weather?

 

I knew it! I knew it!

 

More serious: a library is indeed a place where you can find books. Meteorology is a field which is surely described in a nice book. You can also pick it up in the geography lessons at school.

 

A cold front is a weather transition where cold air is pushing into warmer air. These are simply caused by cold air moving into warm air. And air is moving around because of pressure differences.

Read more: http://en.wikipedia.org/wiki/Cold_front

 

I don't get it. In higher elevations in the atmosphere there is less pressure, right? If so shouldn't air from lower regions of the atmosphere where there is more pressure climb up to higher regions of the atmosphere where there is less pressure? If not, why doesn't it happen?

 

Wait a minute... Wikipedia answers the question but I would like a more lengthy explanation:

 

"Hydrostatic equilibrium can explain why the Earth's atmosphere does not collapse to a very thin layer on the ground. In the atmosphere, the pressure of air decreases with increasing altitude. This causes an upward force, called the pressure gradient force, which tries to smooth over pressure differences. The force of gravity, on the other hand, almost exactly balances this out, keeping the atmosphere bound to the earth and maintaining pressure differences with altitude. Without the pressure gradient force, the atmosphere would collapse to a much thinner shell around the earth, and without the force of gravity, the pressure gradient force would diffuse the atmosphere into space, leaving Earth with hardly any atmosphere".

 

http://en.wikipedia.org/wiki/Hydrostatic_equilibrium

Edited March 6, 2009 by Uri

[CaptainPanic]

You are right: the higher up in the atmosphere, the higher the pressure. That's simply because the air on the top is pushing down on the air below it (because of gravity).

 

The atmosphere is in a force-equilibrium. While it's true that air wants to go from a high pressure to low pressure, gravity is pulling it the other way...

 

However, if the low and high pressure are situated next to each other, like in high and low pressure regions (shown with the "L" and "H" on the weather forecast), then it will move, and you get wind. This wind can then be cold or warm, and if it crashes into another pocket of air of a different temperature, it will also get a vertical movement. The cold air, moving horizontally into the hot air is the same pressure (because it's at the same altitude) - but cold air is more dense so it will go under the hot air, effectively pushing the hot air up. This is the cold front.

[jersincl]

There is a big man with a white beard who blows his cheeks out and cold wind

comes out. I saw a picture of this in kindergarden 45 years ago and I still know the answer. Hope this helps. hehehehehehehe