On Tue, 9 Dec 2014 13:34:04 -0800 (PST), Graham Easterling
wrote:

Alan may remember jet skis towing surfers out at Porthcurno (well Pedne-Vounder to be exact ) during our RIB ride in rather a large swell, including a bumpy ride across the Bay from Perranuthnoe.

I do :-)

--
Alan White
Mozilla Firefox and Forte Agent.
By Loch Long, twenty-eight miles NW of Glasgow, Scotland.
Webcam and weather:- http://windycroft.co.uk/weather

Malcolm wrote:


In article , Norman
writes
Graham Easterling wrote:

On Tuesday, December 9, 2014 6:09:21 PM UTC, Togless wrote:
"Malcolm" wrote (quoting the Daily Express, I think):

"The deepest and most powerful low pressure system for A CENTURY
is currently hurtling towards the west coast where mammoth 50-ft
waves threaten mayhem."

Are they claiming that it's already the deepest and most powerful low
pressure system for a century (which should be easy enough to verify or
refute), or just that they expect it to be?

It certainly looks quite lively out there in the Atlantic...

Whilst 50' waves are very large, they occur in the north Atlantic every
winter. In fact 60' waves have been surfed in Ireland & Portugal.


It depends, of course, on whether we're talking about significant wave
height (which is the usual way to describe the sea state) or the maximum
wave height.

Down the more exposed parts of the west coast of the British Isles the once
in 50 year extreme significant wave height is around 16 metres (about 52
feet) so this would be a rare occurrence . West Cornwall is a little lower
with 14 metres (about 46 feet). However, with a significant wave height of
16 metres the highest occasional individual waves would be 27-30 metres
(around 90-100 feet).

So, if we are talking about 50 feet as a significant wave height around the
west coast of the British Isles this would be a rare and very notable
occurrence but if we are talking about a maximum wave height then it would
not be a notable occurrence.

I notice that the forecast of the sea state for my local inshore water, Mull
of Kintyre to Ardnamuchan Point, is:

"Very rough or high, becoming very high, occasionally phenomenal later in
west."

How high is "phenomenal"?


"Phenomenal" is defined as a significant height of more than 14 metres. This
implies occasional individual waves up to 22-25 metres (70-80 feet).

Not a good time to be at sea though I have to admit that I enjoyed a really
good storm when I worked on the Ocean Weather Ships :-)

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org

Graham Easterling wrote:

On Tuesday, December 9, 2014 7:21:02 PM UTC, Norman wrote:
Graham Easterling wrote:

On Tuesday, December 9, 2014 6:09:21 PM UTC, Togless wrote:
"Malcolm" wrote (quoting the Daily Express, I think):

"The deepest and most powerful low pressure system for A CENTURY
is currently hurtling towards the west coast where mammoth 50-ft
waves threaten mayhem."

Are they claiming that it's already the deepest and most powerful low
pressure system for a century (which should be easy enough to verify or
refute), or just that they expect it to be?

It certainly looks quite lively out there in the Atlantic...

Whilst 50' waves are very large, they occur in the north Atlantic every
winter. In fact 60' waves have been surfed in Ireland & Portugal.


It depends, of course, on whether we're talking about significant wave
height (which is the usual way to describe the sea state) or the maximum
wave height.

Down the more exposed parts of the west coast of the British Isles the once
in 50 year extreme significant wave height is around 16 metres (about 52
feet) so this would be a rare occurrence . West Cornwall is a little lower
with 14 metres (about 46 feet). However, with a significant wave height of
16 metres the highest occasional individual waves would be 27-30 metres
(around 90-100 feet).

So, if we are talking about 50 feet as a significant wave height around the
west coast of the British Isles this would be a rare and very notable
occurrence but if we are talking about a maximum wave height then it would
not be a notable occurrence.


--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org

I assumed from the wording, rightly or wrongly, that it was the maximum wave
height that was being referred to.

Dramatic Video of recent 60' reef break surfing in Portugal
https://www.youtube.com/watch?v=lFyp1o9CAvs (You can skip the Ad)

Move the decimal point to the left, and 6' is still big as far as I'm
concerned, these men are clearly mad!

Graham



The highest measured wave height I have seen so far is 15.9 metres (52 ft)
significant height at 0700z from the buoy at 59.1N 11.7W. It has decreased a
little since then and at 1300z it was 14.0m. The once in 50 year extreme
significant wave height for that location is of the order of 18-19 metres so,
for that location at least, it's a fair bit short of a once in 50 year event,
never mind a once in 100 year event.

At 53.2N 15.7W the highest reported so far is 14.1 metres significant height at
0600z. The once in 50 year event for that location is also around 18-19 metres.


--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org

On Tuesday, 9 December 2014 19:33:17 UTC, Norman wrote:
Norman wrote:

Graham P Davis wrote:

On Tue, 9 Dec 2014 18:09:20 -0000
"Togless" wrote:

"Malcolm" wrote (quoting the Daily Express, I think):

"The deepest and most powerful low pressure system for A CENTURY
is currently hurtling towards the west coast where mammoth 50-ft
waves threaten mayhem."

Are they claiming that it's already the deepest and most powerful
low pressure system for a century (which should be easy enough to
verify or refute), or just that they expect it to be?


I knew I was getting old but seem to be getting forgetful too. If
that piddling little depression is the deepest for a century and I
remember lots deeper than this, where'd my telegram from the queen go?

There was one that I can remember 20 or 30 years ago that got below 920 mb SW
of Iceland. I think that one holds the record.

Stephen Burt has done some research in this field that was published in
'Weather'


It was January 1993 to SE of Iceland. See the following

http://onlinelibrary.wiley.com/doi/1...854.x/abstract

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org

Interesting match of phases:
............. Dec 16 19:13 ............
............. Dec 24 00:43 ............
Nov 14 15:16 Jan 1 03:38 ............ Thundery
Nov 22 12:32 Jan 8 12:37 ............ Volcanic
Nov 29 10:06 Jan 15 04:01 ............ Volcanic
............. Jan 22 18:27 ............
............. Jan 30 23:20 ............
............. Feb 6 23:55 ............

So; about those tides having nothing to do with the moon. laughing

In message ,
Richard Dixon writes
Ye Gods. That's this winter's buzzword sorted. Come in Polar Vortex,
your time is up. Move over The Beast From The East.

Those who find the term "weather bomb" unnecessarily dramatic might be
amused by the third leader in today's Telegraph:

http://www.telegraph.co.uk/news/weat...blow-over.html

Whoever wrote it seems to have an unexpectedly good knowledge of
meteorology.
--
I'm not paid to implement the recognition of irony.
(Taken, with the author's permission, from a LiveJournal
post)

"John Hall" wrote in message
.. .

Whoever wrote it...
================

'Isobars approaching from the west rolled themselves up like woodlice.'

Who else could it be than Rev WL?

In message , General
writes
"John Hall" wrote in message
. ..

Whoever wrote it...
================

'Isobars approaching from the west rolled themselves up like woodlice.'

Who else could it be than Rev WL?

Huh? I'm afraid you've lost me.
--
I'm not paid to implement the recognition of irony.
(Taken, with the author's permission, from a LiveJournal
post)