Puzzled by today's tides

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Ex-SolentBoy

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I am local so should know this, but I am puzzled.

High tide Yarmouth today is about 10:00 and is quite high, 3.1 metres. Thats about as high as it ever gets here.

Despite this, at 10:10 this morning the shingles bank near Hurst was quite exposed.
I know the pressure is high (1033 at the moment), but I do not recall seeing the bank at the top of a big spring tide before.

Any thoughts?
 
SolentBoy said:
I am local so should know this, but I am puzzled.

High tide Yarmouth today is about 10:00 and is quite high, 3.1 metres. Thats about as high as it ever gets here.

Despite this, at 10:10 this morning the shingles bank near Hurst was quite exposed.
I know the pressure is high (1033 at the moment), but I do not recall seeing the bank at the top of a big spring tide before.

Any thoughts?
Click to expand...


high pressure will suppress the tide, to what degree, i dont know, maybe simon the weatherman could explain.
 
The moon tonight is closer to us than it has been for eighteen years. For the next two days there will be higher and lower spring tides as a consequence.

We should be glad we do not have a big low on top of us coupled with strong onshore gales - that would make life interesting - particularly on the East coast.
 
chinita said:
The moon tonight is closer to us than it has been for eighteen years. For the next two days there will be higher and lower spring tides as a consequence.

We should be glad we do not have a big low on top of us coupled with strong onshore gales - that would make life interesting - particularly on the East coast.
Click to expand...

Understand that. That is what makes it even more astounding. We are at the top of one of the biggest tides of the year, and the bank is exposed!
 
According to Chimet the tide height at Bramblemet this morning was only shade under 5 metres and about 0.5 higher that it was on the last spring tides a fortnight ago.

Pressure was very high at about 1036mb. Thats 23mb above the average on which tidal predictions are based.
1mb can cause 1cm difference in tide but other meteorological factors can also have a very significant effect.

The NTSLF tide gauge at Portsmouth shows the tide this morning to be only about 0.1m below the predicted height.
http://www.pol.ac.uk/ntslf/sadata_tgi_ntslf_v2.php?code=Portsmouth&span=1
 
Just spoke to a local fisherman. *He says it is nothing to do with pressure. A bank just builds up there on occasions. He says it happens every few years. It lasts a few weeks and he has seen it over 10ft high.
 
chinita said:
The moon tonight is closer to us than it has been for eighteen years.
Click to expand...

<panto>

Oh no it's not.

</panto>

Well, not significantly.

The moon is in an elliptical orbit around us and it would take something really drastic to move it closer to us. You can find the dates and times if all thirteen lunar perigees - although this is the closest, the one on 26th September is only 470km more, which in astronomical terms is three fifths of b*gger all. On January 30th last year the difference was 15km.

What's slightly unusual at the moment is that the long axis of the ellipse is pointing at the sun with the perigee on the opposite side, from the sun, so we have a full moon at perigee. You can find the dates and times iof all thirteen lunar perigees.

It does mean that the spring tide will be a wee bit higher than usual.
 
I came out of the Needles channel two weeks ago at the top of HW and I was amazed at how two shingle huge banks were exposed, one was right at the seaward end near the Bridge and close to the channel, from a distance it looked like a ship coming in and it was some time before it made sense.

As we got closer their were a stream of ships passing and we tucked right over on the edge of the channel, we were within about 10 metres of the bank but still in deep water, scary stuff!

Must be like the side of a house at LW
 
Ubergeekian said:
<panto>

Oh no it's not.

</panto>

Well, not significantly.

The moon is in an elliptical orbit around us and it would take something really drastic to move it closer to us. You can find the dates and times if all thirteen lunar perigees - although this is the closest, the one on 26th September is only 470km more, which in astronomical terms is three fifths of b*gger all. On January 30th last year the difference was 15km.

What's slightly unusual at the moment is that the long axis of the ellipse is pointing at the sun with the perigee on the opposite side, from the sun, so we have a full moon at perigee. You can find the dates and times iof all thirteen lunar perigees.

It does mean that the spring tide will be a wee bit higher than usual.
Click to expand...

Yes, that is what I meant to say.
 
colvic987 said:
high pressure will suppress the tide, to what degree, i dont know, maybe simon the weatherman could explain.
Click to expand...

In old money, it used to be said that one inch of mercury would affect the tide by one foot. It may, however be a factor of the local tidal range, and tide heights can be affected by lots of other things.
 
NormanS said:
In old money, it used to be said that one inch of mercury would affect the tide by one foot.
Click to expand...

Aye, they knew what they were talking about back then. It's no coincidence that the specific gravity of mercury is roughly 1 foot over 1 inch times (actually about 13 times) that of sea water.

As for the National Geographic. Well, "The March 19 supermoon, as it's called, will be visible "pretty much any time during the night," said Geza Gyuk, astronomer at the Adler Planetarium in Chicago."

If I suggest the full moon's visible all night, can I call myself an astronomer, too?

On second thoughts, maybe I'd rather not spend my winters in Chicago.
 
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SolentBoy said:
Just spoke to a local fisherman. *He says it is nothing to do with pressure. A bank just builds up there on occasions. He says it happens every few years. It lasts a few weeks and he has seen it over 10ft high.
Click to expand...

What is unusual about this bank is that it has been there since November. There were a couple of ribs parked on it yesterday. Could be the location of the shortest rti race....
 
Unexpected sandbanks

Something similar here at Chichester Entrance. I walked on West Pole Sands at LW yesterday and the highest part now needs 3.2m* to cover compared with the previous 1.5m*.
However, the explanation is not meteorological but recent beach replenishment by the Council, whose annual attempt to protect waterside properties is already being redistributed elsehere!

* data from Chimet readings BUT am not convinced that the new sensor is accurate yet. Any comments?
 
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