JohnDH wrote:


One thing that causes storm surge is air pressure.

Certainly is, but has nothing like the effect on onshore gale has.

If you look at the predicted tides for say Newlyn, allow for the
atmospheric pressure (simple enough calculation) and there is often a
significant difference to the observed tide. The tide is invariably
higher than predicted with a strong onshore wind, and the difference is
particularly great wth depressions moving in from the south. I've seen
cases where the astronomically predicted high tide has been exceeded 90
minutes prior to high tide.

As far as Cornwall is concerned, differences in actual/predicted tide
due to pressure are very small compared with the more extreme wind
induced swell & surges. A SE gale is particularly damaging, even on
fairly small tides.

Graham
Penzance

Holiday Cottage www.easterling.freeserve.co.uk
Penzance Weather www.easterling.freeserve.co.uk/weather.html

Graham Easterling wrote:

JohnDH wrote:


One thing that causes storm surge is air pressure.

Certainly is, but has nothing like the effect on onshore gale has.


I took 'air pressure' in your post as meaning atmospheric pressure. On
re-reading it I think you meant it in the wider sense, ie including
wind & gales.

Graham
Penzance

Graham Easterling wrote:
Graham Easterling wrote:

JohnDH wrote:

One thing that causes storm surge is air pressure.

Certainly is, but has nothing like the effect on onshore gale has.

I took 'air pressure' in your post as meaning atmospheric pressure. On
re-reading it I think you meant it in the wider sense, ie including
wind & gales.

Never mind the who said what let's just look at the simple physics at
sea level. How much contact does the air stream have on the sea?

We know full well that water passing over a solid surface is not moving
very fast. In fact at the edge of a stream, it might even be flowing
uphill.

So what direction is the air current at contact point with the water
moving? Bearing in mind that it moves millions of tons an hour at some
4 knots minimum north of the United States of American coast and west
of the Canadian one.

And it does this for quite a depth.

Just tell me how and I will shut my gob.

If you can't then shut the **** up yourselves, telling me off for
stating the bloody obvious and knowing nothing better yourselves. You
damned sheep.

Graham Easterling wrote:

I took 'air pressure' in your post as meaning atmospheric pressure. On
re-reading it I think you meant it in the wider sense, ie including
wind & gales.

Graham
Penzance

That's correct.

Following on from what you said about the effect of gales on tide
heights. Two years ago, there was westerly storm force winds that
coincided with a spring high tide. Sea levels were reported to have
continued to rise after high water, giving Oban a good soaking. So I
think we are singing from the same hymn sheet.

Cheers

John DH

Weatherlawyer wrote:

If you can't then shut the **** up yourselves, telling me off for
stating the bloody obvious and knowing nothing better yourselves. You
damned sheep.


When you go back to school to learn some physics, can you ask the
teacher to explain what good manners are as well.

Thank you

John DH

JohnDH wrote:

Graham Easterling wrote:

I took 'air pressure' in your post as meaning atmospheric pressure. On
re-reading it I think you meant it in the wider sense, ie including
wind & gales.

Graham
Penzance

That's correct.

Following on from what you said about the effect of gales on tide
heights. Two years ago, there was westerly storm force winds that
coincided with a spring high tide. Sea levels were reported to have
continued to rise after high water, giving Oban a good soaking. So I
think we are singing from the same hymn sheet.

Cheers

John DH


John,

I'm sure that would be right. Onshore gales can cause a considerable
time delay to the ebb tide. Comparing graphs for predicted tide heights
and actual tide heights in these conditions typically shows the biggest
discrepancy around 1 hour after high tide.

Graham

On a tatty piece of sub-ether Weatherlawyer at
said...

Graham Easterling wrote:
Graham Easterling wrote:

JohnDH wrote:

One thing that causes storm surge is air pressure.

Certainly is, but has nothing like the effect on onshore gale has.

I took 'air pressure' in your post as meaning atmospheric pressure. On
re-reading it I think you meant it in the wider sense, ie including
wind & gales.

Never mind the who said what let's just look at the simple physics at
sea level. How much contact does the air stream have on the sea?

We know full well that water passing over a solid surface is not moving
very fast. In fact at the edge of a stream, it might even be flowing
uphill.

So what direction is the air current at contact point with the water
moving? Bearing in mind that it moves millions of tons an hour at some
4 knots minimum north of the United States of American coast and west
of the Canadian one.

And it does this for quite a depth.

Just tell me how and I will shut my gob.

If you can't then shut the **** up yourselves, telling me off for
stating the bloody obvious and knowing nothing better yourselves. You
damned sheep.



1: If you can't speak without using bad language, then don't speak. I
realise this is too much for us all to expect but if you can't, you
shouldn't.

2: Go read http://en.wikipedia.org/wiki/El_nino and learn something.

3: BAAAAAAAAAAAAAAAAAA!!!
--
Rob C. Overfield
Hull

Robb C. Overfield wrote:
On a tatty piece of sub-ether Weatherlawyer at
said...

Graham Easterling wrote:
Graham Easterling wrote:

JohnDH wrote:

One thing that causes storm surge is air pressure.

Certainly is, but has nothing like the effect on onshore gale has.

I took 'air pressure' in your post as meaning atmospheric pressure. On
re-reading it I think you meant it in the wider sense, ie including
wind & gales.

Never mind the who said what let's just look at the simple physics at
sea level. How much contact does the air stream have on the sea?

We know full well that water passing over a solid surface is not moving
very fast. In fact at the edge of a stream, it might even be flowing
uphill.

So what direction is the air current at contact point with the water
moving? Bearing in mind that it moves millions of tons an hour at some
4 knots minimum north of the United States of American coast and west
of the Canadian one.

And it does this for quite a depth.

Just tell me how and I will shut my gob.

If you can't then shut the **** up yourselves, telling me off for
stating the bloody obvious and knowing nothing better yourselves. You
damned sheep.



1: If you can't speak without using bad language, then don't speak. I
realise this is too much for us all to expect but if you can't, you
shouldn't.

2: Go read http://en.wikipedia.org/wiki/El_nino and learn something.

3: BAAAAAAAAAAAAAAAAAA!!!
--
Rob C. Overfield
Hull

Seconded! This character tried to come over as an overbearing
condescending smartalec on an antipodean forum - and got promptly put
in his place.

It is his type of personality that reminds one of the downside of open
forums....