At long last A High of significance - had a quick look back at my pressure
readings this year and today has seen the highest pressure in Leeds since 17
March. It's now 1038mb and still rising.

"Rob Brooks" wrote in message
...
At long last A High of significance - had a quick look back at my pressure
readings this year and today has seen the highest pressure in Leeds since
17 March. It's now 1038mb and still rising.

Is this really surprising, though?
In terms of pressure readings isn't a winter anticyclone likely to be more
'intense' than a summer one?
--
Col

Bolton, Lancashire
160m asl

"Col" wrote in message
...

"Rob Brooks" wrote in message
...
At long last A High of significance - had a quick look back at my
pressure readings this year and today has seen the highest pressure in
Leeds since 17 March. It's now 1038mb and still rising.

Is this really surprising, though?
In terms of pressure readings isn't a winter anticyclone likely to be more
'intense' than a summer one?

dynamics lesson
Why? And don't say because the air is colder as that would not be the right
answer, this high has 552DAM air entrained. The reason is all in the
dynamics - this high developed at the left entrance of a confluent relaxing
upper trough and right exit of an Atlantic jet both regions of upper level
convergence due to ageostrophic wind components. Also we had a deep low with
a lot of wind and kinetic energy which has been converted to potential
energy helping to raise pressure substantially. This is a warm and intense
high.
/dynamics lesson

Will
--

"Will Hand" wrote in message
...

"Col" wrote in message
...

"Rob Brooks" wrote in message
...
At long last A High of significance - had a quick look back at my
pressure readings this year and today has seen the highest pressure in
Leeds since 17 March. It's now 1038mb and still rising.

Is this really surprising, though?
In terms of pressure readings isn't a winter anticyclone likely to be
more
'intense' than a summer one?

dynamics lesson
Why? And don't say because the air is colder as that would not be the
right answer, this high has 552DAM air entrained. The reason is all in
the dynamics - this high developed at the left entrance of a confluent
relaxing upper trough and right exit of an Atlantic jet both regions of
upper level convergence due to ageostrophic wind components. Also we had a
deep low with a lot of wind and kinetic energy which has been converted to
potential energy helping to raise pressure substantially. This is a warm
and intense high.
/dynamics lesson

Will, I don't understand any of that
--
Col

Bolton, Lancashire
160m asl

On Thu, 10 Sep 2009 at 17:07:48, Col wrote
in uk.sci.weather :


"Rob Brooks" wrote in message
...
At long last A High of significance - had a quick look back at my pressure
readings this year and today has seen the highest pressure in Leeds since
17 March. It's now 1038mb and still rising.

Is this really surprising, though?
In terms of pressure readings isn't a winter anticyclone likely to be more
'intense' than a summer one?

I wouldn't quite call this winter yet - mind you, the temperature did
drop to 4.6C last night...
--
Paul Hyett, Cheltenham (change 'invalid83261' to 'blueyonder' to email me)

"Col" wrote in message
...

"Will Hand" wrote in message
...

"Col" wrote in message
...

"Rob Brooks" wrote in message
...
At long last A High of significance - had a quick look back at my
pressure readings this year and today has seen the highest pressure in
Leeds since 17 March. It's now 1038mb and still rising.

Is this really surprising, though?
In terms of pressure readings isn't a winter anticyclone likely to be
more
'intense' than a summer one?

dynamics lesson
Why? And don't say because the air is colder as that would not be the
right answer, this high has 552DAM air entrained. The reason is all in
the dynamics - this high developed at the left entrance of a confluent
relaxing upper trough and right exit of an Atlantic jet both regions of
upper level convergence due to ageostrophic wind components. Also we had
a deep low with a lot of wind and kinetic energy which has been converted
to potential energy helping to raise pressure substantially. This is a
warm and intense high.
/dynamics lesson

Will, I don't understand any of that
--

Sorry Col, I forgot you hadn't done an advanced forecasting course or the
Met. degree at Reading :-)

To put it more simply, two upper air flow patterns occurred close together
where the wind flows were such that they produced a coming together of air
high up in the atmosphere at around 30000 feet. This air was forced to come
down as the tropopause higher up was acting as a lid. This downward motion
transported masses of air into one place and pressure began to rise at the
surface. Meanwhile at the same time a very deep low began to fill up and the
kinetic energy of the fast moving air was converting to potential energy
(energy is never lost) reinforcing the effect of the coming together of the
air flows.

Is that better?

Will
--

On 10 Sep, 21:11, "Will Hand" wrote:


Will, I don't understand any of that
--

Sorry Col, I forgot you hadn't done an advanced forecasting course or the
Met. degree at Reading :-)

Is that better?

Will


What an utterly pretentious response that is, Will. Please grow up and
have some respect for the majority on this newsgroup who don't have
your background but who are asking perfectly reasonable questions in
order to seek greater understanding and not to be used as target
practice for patronising statements such as the ones above. I suggest
an apology to Col is in order.

--
Stephen Burt
Stratfield Mortimer, Berkshire

"Stephen Burt" wrote in message
...
On 10 Sep, 21:11, "Will Hand" wrote:


Will, I don't understand any of that
--

Sorry Col, I forgot you hadn't done an advanced forecasting course or the
Met. degree at Reading :-)

Is that better?

Will


What an utterly pretentious response that is, Will. Please grow up and
have some respect for the majority on this newsgroup who don't have
your background but who are asking perfectly reasonable questions in
order to seek greater understanding and not to be used as target
practice for patronising statements such as the ones above. I suggest
an apology to Col is in order.

--
Stephen Burt
Stratfield Mortimer, Berkshire

I didn't understand too much of that either but as this is the "uk.sci"
heirachy of usenet I guess a bit of science is to be expected.

Paul

Yes Will, that's OK for the dynamics. But the next step is to equate this to
the physical consequence, the thermodynamic effect, of the dynamics you
describe. The effect of the upper level convergence is to lift a substantial
layer of the upper troposphere and lower stratosphere, which of course
results in a cooling of the layer, especially well marked in the
stratosphere, where the lapse is zero or negative. It is this cooling that
more than compensates for the tropospheric warming due to subsidence and
advection, and produces the increase in pressure at the base of the
atmosphere. Mass can only increase in an atmospheric column if there is a
corresponding decrease in temperature. A map of the pressure or height field
at any level in the atmosphere is a direct reflection of the mean
temperature field (or thickness) in the atmosphere above that level. A high
pressure 'cell' at any level will be a reflection of a cold anomaly above
that level, and a warm anomaly will be found above a low pressure area.

--
Bernard Burton
Wokingham, Berkshire, UK.

Satellite images at:
www.woksat.info/wwp.html

"Will Hand" wrote in message
...

"Col" wrote in message
...

"Rob Brooks" wrote in message
...
At long last A High of significance - had a quick look back at my
pressure readings this year and today has seen the highest pressure in
Leeds since 17 March. It's now 1038mb and still rising.

Is this really surprising, though?
In terms of pressure readings isn't a winter anticyclone likely to be
more
'intense' than a summer one?

dynamics lesson
Why? And don't say because the air is colder as that would not be the
right
answer, this high has 552DAM air entrained. The reason is all in the
dynamics - this high developed at the left entrance of a confluent
relaxing
upper trough and right exit of an Atlantic jet both regions of upper level
convergence due to ageostrophic wind components. Also we had a deep low
with
a lot of wind and kinetic energy which has been converted to potential
energy helping to raise pressure substantially. This is a warm and intense
high.
/dynamics lesson

Will
--

On Sep 10, 11:28*pm, "Bernard Burton" b.j.burton-
wrote:
Yes Will, that's OK for the dynamics. But the next step is to equate this to
the physical consequence, the thermodynamic effect, of the dynamics you
describe. The effect of the upper level convergence is to lift a substantial
layer of the upper troposphere and lower stratosphere, which of course
results in a cooling of the layer, especially well marked in the
stratosphere, where the lapse is zero or negative. It is this cooling that
more than compensates for the tropospheric warming due to subsidence and
advection, and produces the increase in pressure at the base of the
atmosphere. Mass can only increase in an atmospheric column if there is a
corresponding decrease in temperature. A map of the pressure or height field
at any level in the atmosphere is a direct reflection of the mean
temperature field (or thickness) in the atmosphere above *that level. A high
pressure 'cell' at any level will be a reflection of a cold anomaly above
that level, and a warm anomaly will be found above a low pressure area.

--
Bernard Burton
Wokingham, Berkshire, UK.

Satellite images at:www.woksat.info/wwp.html

"Will Hand" wrote in message

...





"Col" wrote in message
...

"Rob Brooks" wrote in message
...
At long last A High of significance - had a quick look back at my
pressure readings this year and today has seen the highest pressure in
Leeds since 17 March. It's now 1038mb and still rising.

Is this really surprising, though?
In terms of pressure readings isn't a winter anticyclone likely to be
more
'intense' than a summer one?

dynamics lesson
Why? And don't say because the air is colder as that would not be the
right
answer, this high has 552DAM air entrained. The reason is all in the
dynamics - this high developed at the left entrance of a confluent
relaxing
upper trough and right exit of an Atlantic jet both regions of upper level
convergence due to ageostrophic wind components. Also we had a deep low
with
a lot of wind and kinetic energy which has been converted to potential
energy helping to raise pressure substantially. This is a warm and intense
high.
/dynamics lesson

Will
--- Hide quoted text -

- Show quoted text -

Thank goodness someone has come up with a lucid explanation of
where the extra air is, to put it simply. i used to be a bit puzzled
about this. If you go to 30,000 feet in an anticyclone the pressure
is still higher than normal for that height so one is still forced to
ask oneself where all this "extra air" is. Above 30,000 feet,
obviously. I knew it must be in the stratosphere but it is now clear
to me how it gets there and why it causes high pressure. One could
say that the dynamical processes try to lift the lid and the lid
fights back with adiabatic cooling.
It's all a bit clearer now. Thanks, Bernard.

Tudor Hughes, Warlingham, Surrey.