What produces high and low meteorological pressure areas? I know the common explanation is that the hot air raises due to lower density and creates a low pressure zone and the air then flows from high pressure (cold) to low pressure (warm) areas, but that means that the wind would blow all the time from cold areas to the warm areas, and that is not the case. Many times the wind blows from warm areas to cold areas, the warm wind. Seems to me that this phenomenon has something to do with the enormous weight of water contained in the clouds, exercising a pressure on the air underneath...the pressure would push the air towards the outside of the clouds, like a piston, resulting in a low pressure area transforming into a high pressure and then the wind would be a warm one blowing to some cold areas. Please tell me if you think that my explanation is valid and if not give another.  
 A: A semi-stable low pressure region results from circular wind.  The centripetal
acceleration of the wind is sustained by the pressure gradient (low pressure
in the 'eye' of the hurricane, for example).   Such low pressure regions
aren't going to shrink like a limp balloon, because the surrounding wind 
is in a kind of stable orbit.
The circular wind, in turn, may be caused by hot air rising, because
the latitudinal momentum of air at ground level remains unchanged when that
air mass rises.   The unchanged latitudinal momentum, on a rotating planet,
means that the rising air achieves some ground speed as it rises,
and the amount of ground speed will vary according to the varying 
causes of the heated air, and with the latitude itself.
Cold air is denser than warm air, and it takes time to mix, so a
cold front can carry a high pressure signature.
Then there's moisture, and the various kinds of precipitation which
move heat and mass about... it's apparently possible for ice pellets
to rise/fall/rise and grow to hailstones as large as melons.   There's
a lot of air movement on this planet, and it's never simple, but
it surely always has some valid physical explanation.
