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Old November 6th 18, 04:12 PM posted to uk.sci.weather
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Default High Tide chaos in Penzance

The current high tide is not that big astronomically, but is higher in Penzance than I observed at any time last winter, and higher than it was during then red coastal flood warning for Penzance a few weeks back. (We currently have an orange warning.)

This is the real time data from Newlyn https://www.ntslf.org/data/realtime?port=Newlyn , but that's only half the story, there are some wave setup surges which raise the level significantly for a while.

I've just got back home after having tried to get along the prom, expecting to see it coming over in the normal way.

There is some depth of water over the bottom of the Abbey slip, up to the front doors of the houses. In the harbour the sea is washing into the car park & up to the door of the Harbourside cafe. The police had closed the prom which is a mass of water & seaweed, directed the traffic up a narrow 1 way street (not the best option,) and caused traffic chaos. Anyway, I'm back now!

All this despite the wind not being that strong, and the waves not that big, but the direction the weather is coming from has made the tide exceptional, forget what the tide table says!

Graham
Penzance

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Old November 6th 18, 06:57 PM posted to uk.sci.weather
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Default High Tide chaos in Penzance

On 06/11/2018 16:12, Graham Easterling wrote:
The current high tide is not that big astronomically, but is higher in Penzance than I observed at any time last winter, and higher than it was during then red coastal flood warning for Penzance a few weeks back. (We currently have an orange warning.)

This is the real time data from Newlyn https://www.ntslf.org/data/realtime?port=Newlyn , but that's only half the story, there are some wave setup surges which raise the level significantly for a while.

I've just got back home after having tried to get along the prom, expecting to see it coming over in the normal way.

There is some depth of water over the bottom of the Abbey slip, up to the front doors of the houses. In the harbour the sea is washing into the car park & up to the door of the Harbourside cafe. The police had closed the prom which is a mass of water & seaweed, directed the traffic up a narrow 1 way street (not the best option,) and caused traffic chaos. Anyway, I'm back now!

All this despite the wind not being that strong, and the waves not that big, but the direction the weather is coming from has made the tide exceptional, forget what the tide table says!

Graham
Penzance


This was the advisory I circulated this afternoon to the local
Southampton,Hythe and Cowes flood action group.
For Soton both high tides tonight 4.5m and anything over 5.4m tide +
surge would trigger an action plan, so even at 4.5 +0.6 is ok.

Lymington residual
http://www.channelcoast.org/data_man...arts/?chart=87

currently 0.4m

Quote
A reminder that NTSLF doesn't do southerly gales well, ie stuff from France.
The shipping forecast for today
*****
Wight
Gale Warning: Gale warning issued 5 November 21:43 UTC
Southerly gale force 8 expected later
Wind
South 4 or 5, increasing 6 to gale 8, perhaps severe gale 9 later.
Sea State
Slight or moderate, becoming moderate or rough.
Weather
Rain or showers.
Visibility
Moderate or good, occasionally poor later.

Portland
Southerly gale force 8 expected later
Wind
South 4 or 5, increasing 6 to gale 8, perhaps severe gale 9 later.
Sea State
Slight or moderate, becoming moderate or rough.
Weather
Rain or showers.
Visibility
Moderate or good, occasionally poor later.

*****
GFS has about Force7.5 maximum sustained and widgets to about 0.45m, if
Force 9 then about 0.6m surge. Also AFAIK, surge from the south, more
decoupled from the tide pulse timing so could be either high tide
tonight could be around peak surge time. And of course what the Newlyn
tide gauge says is no predictor, more a case of monitoring the live
winds in the Biscay area this evening and allowing for some attenuation
over France.
GFS has given higher winds in the Eng Channel for tonight in previous runs.

Similarly with 09 Nov, more a case of a surge from the south, currently
the peak of that is around low water, so not bothering to widget that.
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Old November 6th 18, 07:08 PM posted to uk.sci.weather
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Default High Tide chaos in Penzance

On Tuesday, November 6, 2018 at 4:12:53 PM UTC, Graham Easterling wrote:
The current high tide is not that big astronomically, but is higher in Penzance than I observed at any time last winter, and higher than it was during then red coastal flood warning for Penzance a few weeks back. (We currently have an orange warning.)

This is the real time data from Newlyn https://www.ntslf.org/data/realtime?port=Newlyn , but that's only half the story, there are some wave setup surges which raise the level significantly for a while.

I've just got back home after having tried to get along the prom, expecting to see it coming over in the normal way.

There is some depth of water over the bottom of the Abbey slip, up to the front doors of the houses. In the harbour the sea is washing into the car park & up to the door of the Harbourside cafe. The police had closed the prom which is a mass of water & seaweed, directed the traffic up a narrow 1 way street (not the best option,) and caused traffic chaos. Anyway, I'm back now!

All this despite the wind not being that strong, and the waves not that big, but the direction the weather is coming from has made the tide exceptional, forget what the tide table says!

Graham
Penzance


Photo from mid afternoon
https://www.falmouthpacket.co.uk/res...onsive-gallery

Just listened to David Braine on BBC Spotlight SW. For the 2nd day in a row he got the time of high tide hours out. He appears to be running a week behind.

Getting the surf forecast wrong is fair enough, we're used to it, but surely the tide times aren't too difficult, and under the current conditions rather important.

Graham
Penzance
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Old November 6th 18, 07:32 PM posted to uk.sci.weather
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Default High Tide chaos in Penzance

These photos are better

https://www.cornwalllive.com/news/co...nzance-2190151

Graham
Penzance
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Old November 6th 18, 08:07 PM posted to uk.sci.weather
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Default High Tide chaos in Penzance

In the last hour 40 knots at the Channel Light Vessel, near enough Force
9, so MetO a better call than GFS.
NTSLF surge prediction for Pompey (proxy for Soton as the shallow water
harmonics make Soton difficult for big data NTSLF) was only a surge of
0.2m for tonight.
Will it be nearer 0.6m surge ?


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Old November 7th 18, 12:05 PM posted to uk.sci.weather
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Default High Tide chaos in Penzance

On Tuesday, November 6, 2018 at 4:12:53 PM UTC, Graham Easterling wrote:
The current high tide is not that big astronomically, but is higher in Penzance than I observed at any time last winter, and higher than it was during then red coastal flood warning for Penzance a few weeks back. (We currently have an orange warning.)

This is the real time data from Newlyn https://www.ntslf.org/data/realtime?port=Newlyn , but that's only half the story, there are some wave setup surges which raise the level significantly for a while.

I've just got back home after having tried to get along the prom, expecting to see it coming over in the normal way.

There is some depth of water over the bottom of the Abbey slip, up to the front doors of the houses. In the harbour the sea is washing into the car park & up to the door of the Harbourside cafe. The police had closed the prom which is a mass of water & seaweed, directed the traffic up a narrow 1 way street (not the best option,) and caused traffic chaos. Anyway, I'm back now!

All this despite the wind not being that strong, and the waves not that big, but the direction the weather is coming from has made the tide exceptional, forget what the tide table says!

Graham
Penzance


I think it's interesting comparing Newlyn
https://www.ntslf.org/data/realtime?port=Newlyn
with Scilly
https://www.ntslf.org/data/realtime?port=St.%20Mary%27s

Demonstrating that the difference between astronomical & actual tide was not so much down to low pressure, but the sea being pushed into Mounts Bay by the persistent strong S wind.

Newlyn actually faces east, the anomaly was greater towards Marazion where the wind was more directly onshore, and there were wave setup surges.

Graham
Penzance
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Old November 7th 18, 12:32 PM posted to uk.sci.weather
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Default High Tide chaos in Penzance

Graham Easterling wrote:

On Tuesday, November 6, 2018 at 4:12:53 PM UTC, Graham Easterling
wrote:
The current high tide is not that big astronomically, but is higher
in Penzance than I observed at any time last winter, and higher
than it was during then red coastal flood warning for Penzance a
few weeks back. (We currently have an orange warning.)

This is the real time data from Newlyn
https://www.ntslf.org/data/realtime?port=Newlyn , but that's only
half the story, there are some wave setup surges which raise the
level significantly for a while.

I've just got back home after having tried to get along the prom,
expecting to see it coming over in the normal way.

There is some depth of water over the bottom of the Abbey slip, up
to the front doors of the houses. In the harbour the sea is washing
into the car park & up to the door of the Harbourside cafe. The
police had closed the prom which is a mass of water & seaweed,
directed the traffic up a narrow 1 way street (not the best
option,) and caused traffic chaos. Anyway, I'm back now!

All this despite the wind not being that strong, and the waves not
that big, but the direction the weather is coming from has made the
tide exceptional, forget what the tide table says!

Graham
Penzance


I think it's interesting comparing Newlyn
https://www.ntslf.org/data/realtime?port=Newlyn
with Scilly
https://www.ntslf.org/data/realtime?port=St.%20Mary%27s

Demonstrating that the difference between astronomical & actual tide
was not so much down to low pressure, but the sea being pushed into
Mounts Bay by the persistent strong S wind.

Newlyn actually faces east, the anomaly was greater towards Marazion
where the wind was more directly onshore, and there were wave setup
surges.

Graham
Penzance


The wind can generate surges which, intuitively, might not be expected.
One oddity that I'm familiar with occurs quite often in the Firth of
Clyde. The flood tide flows rather weakly northwards up the Firth of
Clyde but that's actually a branch of the much stronger main flood
stream that flows towards the ESE, then SSE, from west of Islay,
through the North Channel and into the Irish Sea. NW gales enhance that
main flood stream and, as a consequence of that, the flow northwards
into the Firth of Clyde is also enhanced, resulting in a significant
surge in the northern part of the Firth which is, of course, a dead
end. Water levels can be a metre above predicted levels with a NW gale
blowing. The surge in the northen part of the Firth is greater in NW
gales than in S'ly gales, which is not what might, intuitively, be
expected.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
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Old November 7th 18, 03:07 PM posted to uk.sci.weather
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Default High Tide chaos in Penzance

On 07/11/2018 12:32, Norman Lynagh wrote:
Graham Easterling wrote:

On Tuesday, November 6, 2018 at 4:12:53 PM UTC, Graham Easterling
wrote:
The current high tide is not that big astronomically, but is higher
in Penzance than I observed at any time last winter, and higher
than it was during then red coastal flood warning for Penzance a
few weeks back. (We currently have an orange warning.)

This is the real time data from Newlyn
https://www.ntslf.org/data/realtime?port=Newlyn , but that's only
half the story, there are some wave setup surges which raise the
level significantly for a while.

I've just got back home after having tried to get along the prom,
expecting to see it coming over in the normal way.

There is some depth of water over the bottom of the Abbey slip, up
to the front doors of the houses. In the harbour the sea is washing
into the car park & up to the door of the Harbourside cafe. The
police had closed the prom which is a mass of water & seaweed,
directed the traffic up a narrow 1 way street (not the best
option,) and caused traffic chaos. Anyway, I'm back now!

All this despite the wind not being that strong, and the waves not
that big, but the direction the weather is coming from has made the
tide exceptional, forget what the tide table says!

Graham
Penzance


I think it's interesting comparing Newlyn
https://www.ntslf.org/data/realtime?port=Newlyn
with Scilly
https://www.ntslf.org/data/realtime?port=St.%20Mary%27s

Demonstrating that the difference between astronomical & actual tide
was not so much down to low pressure, but the sea being pushed into
Mounts Bay by the persistent strong S wind.

Newlyn actually faces east, the anomaly was greater towards Marazion
where the wind was more directly onshore, and there were wave setup
surges.

Graham
Penzance


The wind can generate surges which, intuitively, might not be expected.
One oddity that I'm familiar with occurs quite often in the Firth of
Clyde. The flood tide flows rather weakly northwards up the Firth of
Clyde but that's actually a branch of the much stronger main flood
stream that flows towards the ESE, then SSE, from west of Islay,
through the North Channel and into the Irish Sea. NW gales enhance that
main flood stream and, as a consequence of that, the flow northwards
into the Firth of Clyde is also enhanced, resulting in a significant
surge in the northern part of the Firth which is, of course, a dead
end. Water levels can be a metre above predicted levels with a NW gale
blowing. The surge in the northen part of the Firth is greater in NW
gales than in S'ly gales, which is not what might, intuitively, be
expected.


Major gas-pipe repair , with the road closed for 10 weeks round our way
Southampton. They were surprised to see River Itchen water just starting
to come out of the lowest road drain this morning, with 0.4m over the
astronomical predicted tide level.
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Old November 7th 18, 06:23 PM posted to uk.sci.weather
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Default High Tide chaos in Penzance

My widgetting wind to sea-surface windstress to surge for later this
week. Nice to have your own structure , so you can do "what-if" or
"worst-case" , as things can often change in the last few hours, from
model to reality.

As-is for the midnight 09/10Nov 4.5m tide Southampton, a surge of 1m .
For a worst-case, if the GFS projected arc of strongest 55mph wind came
through 4 hours early but same track, then a surge of about 1.15m on the
13:46 otherwise nothing much, on the 4.6m tide of 09 Nov. If it was
delayed 6 hours then it would bump up the midnight tide.
GFS has been set on this track and peak wind timing around low tide for
a couple of days now.
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Old November 8th 18, 01:42 PM posted to uk.sci.weather
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Default High Tide chaos in Penzance

On 07/11/2018 18:23, N_Cook wrote:
My widgetting wind to sea-surface windstress to surge for later this
week. Nice to have your own structure , so you can do "what-if" or
"worst-case" , as things can often change in the last few hours, from
model to reality.

As-is for the midnight 09/10Nov 4.5m tide Southampton, a surge of 1m .
For a worst-case, if the GFS projected arc of strongest 55mph wind came
through 4 hours early but same track, then a surge of about 1.15m on the
13:46 otherwise nothing much, on the 4.6m tide of 09 Nov. If it was
delayed 6 hours then it would bump up the midnight tide.
GFS has been set on this track and peak wind timing around low tide for
a couple of days now.


Latest advisory to the flood wardens of our flood acttion group, should
be a warning tomorrow

GFS 06Z run has upped the winds again.
Now widgetting for the 00:02 4.5m Soton 1HW of 10 Nov as-is surge
widgets to 0.85m and if the middling wind pulse comes through 2 hours
earlier (too close to call for these sort of resolutions) then 1.05m
With that scenario 55mph S winds in IoW area around 1HW.
It looks as though NTSLF will give 0.5m for Pompey high tide , so
another 0.3m or so for Soton looks consistent with 2016 southerly gale
examples.
Whats the betting the EA won't get their finger out until about 18:00
tomorrow?



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