As of 11.30 am on the 15th Dec the current News 24 forecast can be
summarised as follows for England and Wales. (Apologies to Scottish and
N.I members but this one seems to be missing you, largely).
Basically the snow is forecast for Wales in the early hours tomorrow and
then spreads to the Midlands in the morning and then Central Southern
England. The SW, London, East Anglia and the S.E should miss the snow
with rain being generally forecast for these areas though no doubt
higher ground in these regions may see a short spell of wet snow.
The striking thing was there was no mention of strong winds or gales at
all other than "over the Channel in Northern France."
Dave

On Dec 15, 11:56*am, Dave Cornwell wrote:
As of 11.30 am on the 15th Dec the current News 24 forecast can be
summarised as follows for England and Wales. (Apologies to Scottish and
N.I members but this one seems to be missing you, largely).
Basically the snow is forecast for Wales in the early hours tomorrow and
then spreads to the Midlands in the morning and then Central Southern
England. The SW, London, East Anglia and the S.E should miss the snow
with rain being generally forecast for these areas though no doubt
higher ground in these regions may see a short spell of wet snow.
The striking thing was there was no mention of strong winds or gales at
all other than "over the Channel in Northern France."
Dave

Usually the strongest winds will be to the right hand side of the
storm's direction - and if the storm is moving at a fair lick it means
the "left-hand-side" winds - i.e. those on the south coast will tend
to be ameliorated. Not always the case when the storm is moving slowly
- so if the storm track has moved further south, then the south coast
may well be out of the firing line.

Richard

It'll be nasty over the northern half of France. Gusts 60-70mph
possible, and 70+ in places, e.g. Brest Peninsula.

8 to 10 metre total sig wave in the Bay of Biscay.

Stephen.

On Dec 15, 2:11*pm, Stephen Davenport wrote:
It'll be nasty over the northern half of France. Gusts 60-70mph
possible, and 70+ in places, e.g. Brest Peninsula.

8 to 10 metre total sig wave in the Bay of Biscay.

Stephen.


Sig Wave height reached 27' at Sevenstones early afternoon, though
it's decreased significantly now.

Waves up to 9 metres along the north Cornish coast recently
http://www.channelcoast.org/data_man...arts/?chart=76
Probably cleaning up a bit now.

This pic is worth a look, taken from the top of the lifeboat slip
http://www.sennen-cove.com/lbtdy.htm .

Let's hope they don't have to launch.

Graham
Penzance

"Stephen Davenport" wrote in message
...
It'll be nasty over the northern half of France. Gusts 60-70mph
possible, and 70+ in places, e.g. Brest Peninsula.

8 to 10 metre total sig wave in the Bay of Biscay.

A red alert has been issued in Spain for the Biscay coast of the Basque
region tomorrow. Waves up to 10m are expected.

On 15/12/11 18:33, Gavino wrote:
"Stephen wrote in message
...
It'll be nasty over the northern half of France. Gusts 60-70mph
possible, and 70+ in places, e.g. Brest Peninsula.

8 to 10 metre total sig wave in the Bay of Biscay.

A red alert has been issued in Spain for the Biscay coast of the Basque
region tomorrow. Waves up to 10m are expected.

Please, what is a "sig wave"?

Hugh

--

Hugh Newbury

www.evershot-weather.org

On Dec 15, 7:07*pm, Hugh Newbury wrote:
On 15/12/11 18:33, Gavino wrote:

"Stephen *wrote in message
...
It'll be nasty over the northern half of France. Gusts 60-70mph
possible, and 70+ in places, e.g. Brest Peninsula.

8 to 10 metre total sig wave in the Bay of Biscay.

A red alert has been issued in Spain for the Biscay coast of the Basque
region tomorrow. Waves up to 10m are expected.

Please, what is a "sig wave"?

Hugh

--

Hugh Newbury

www.evershot-weather.org

=====================================

Sorry... sig = significant. Total significant wave height -- combined
wind wave and swell. Multiply by about 1.63 for maximum wave.

Stephen.

On 15/12/11 19:48, Stephen Davenport wrote:
Please, what is a "sig wave"?

Hugh

--

Hugh Newbury

www.evershot-weather.org

=====================================

Sorry... sig = significant. Total significant wave height -- combined
wind wave and swell. Multiply by about 1.63 for maximum wave.

Stephen.

Thanks Stephen.

Hugh

On Dec 15, 7:48*pm, Stephen Davenport wrote:
On Dec 15, 7:07*pm, Hugh Newbury wrote:





On 15/12/11 18:33, Gavino wrote:

"Stephen *wrote in message
....
It'll be nasty over the northern half of France. Gusts 60-70mph
possible, and 70+ in places, e.g. Brest Peninsula.

8 to 10 metre total sig wave in the Bay of Biscay.

A red alert has been issued in Spain for the Biscay coast of the Basque
region tomorrow. Waves up to 10m are expected.

Please, what is a "sig wave"?

Hugh

--

Hugh Newbury

www.evershot-weather.org

=====================================

Sorry... sig = significant. Total significant wave height -- combined
wind wave and swell. Multiply by about 1.63 for maximum wave.

Stephen.- Hide quoted text -

- Show quoted text -

I always understood it to be mean wave height (trough to crest) of the
highest third of the waves. Certainly, this is how my various books on
sea & surf define it, as do most of the sites showing swell
forecasts.

The wind wave /swell combinations is pretty hard to predict, unlike
the pure swell. Magic Seaweed has a good go, and correctly predicted
the 30' swell of west Cornwall this morning.
http://magicseaweed.com/UK-Ireland-MSW-Surf-Charts/1/

The height of swell generated breaking waves decreases with an onshore
wind (to a point - a severe gale is something else!) A light to
moderate offshore gives the biggest break for a given swell.

Graham
Penzance

Graham Easterling wrote:

On Dec 15, 7:48*pm, Stephen Davenport wrote:
On Dec 15, 7:07*pm, Hugh Newbury wrote:





On 15/12/11 18:33, Gavino wrote:

"Stephen *wrote in message
...
It'll be nasty over the northern half of France. Gusts 60-70mph
possible, and 70+ in places, e.g. Brest Peninsula.

8 to 10 metre total sig wave in the Bay of Biscay.

A red alert has been issued in Spain for the Biscay coast of the Basque
region tomorrow. Waves up to 10m are expected.

Please, what is a "sig wave"?

Hugh

--

Hugh Newbury

www.evershot-weather.org

=====================================

Sorry... sig = significant. Total significant wave height -- combined
wind wave and swell. Multiply by about 1.63 for maximum wave.

Stephen.- Hide quoted text -

- Show quoted text -

I always understood it to be mean wave height (trough to crest) of the
highest third of the waves. Certainly, this is how my various books on
sea & surf define it, as do most of the sites showing swell
forecasts.


Yes, it's the average height of the one-third highes waves in the sea state.
For example, if you have a wave measuring device at a point and you measure the
crest to trough height of 300 successive waves passing that point the
significant height is the average height of the 100 highest waves. The
significant wave height is the standard way of describing a sea state.

The multiplier to get the most probable height of the highest individual wave
is dependent on the period of time considered. The multiplier of 1.63 is
applicable to about a 20-minute period whereas a multiplier of 1.86 is
applicable to a 3-hour period. In other words, for any constant level of
significant wave height the most probable corresponding maximum individual wave
height increases with increasing time. That is, of course, only the most
probable value. In the real world there's a great deal of variability and it is
not at all uncommon to find cases in measured data where the maximum individual
wave height is double the significant wave height, or even higher.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.