[Phys-l] atmospheric highs and lows

[John Denker <jsd@av8n.com>]

On 06/27/2010 11:37 AM, Bernard Cleyet wrote:

> bc  wonders if high pressure exists except WRT a low.

The smart-aleck literal answer is obviously no.  

The highs are only high relative to the lows.
By the same token, the lows are only low relative to the highs.

===

Perhaps a better question would be, do the official
NOAA weather guessers ever have anything to say about 
the high pressure areas?

The answer is yes, but the highs are less exciting
than the lows.

For example, if you look at the current Significant
Weather chart
  http://www.av8n.com/fly/sigwx0000-28jun10.gif
you can see big blue capital H symbols, representing
high pressure.

To a first approximation:

Surface low pressure areas tend to pull themselves 
together, resulting in tight, almost pointlike cyclones 
and sharp, almost one-dimensional weather fronts, 
hence strong winds.  They are associated with rising 
air, hence clouds and bad weather.

Surface high pressure areas tend to spread out, so
they tend to be large and diffuse, with light winds.
They are associated with descending air, hence clear
skies.  They are of more interest to weather mavens 
than to the general public.

=========

Real weather is very very complicated.  You can be
sure that no simple theory fits the facts very well.