On 22/09/2020 11:37, Graham Easterling wrote:



No mystery to us in Southampton.

It's a mystery to me, as it's very different to what I'd expect based
on years of observation & the prevailing weather & sea conditions,
which are particularly significant here with the wave setup
conditions we experience, and the shape of the Bay making it very
wind affected as far as tidal height is concerned.

It is just after the new moon and at an equinox so the geometry is just
about perfect for seeing maximum tidal range. I am at a bit of a loss as
to why it should occur a couple of days after new moon though. Thursday
was perfect new moon and Friday 18/9 was the moon at closest approach.

I guess it is the difference between theory (uniform ocean on a perfect
sphere) and reality with all those nasty continents and coastlines
about. I have the astronomical tidal coefficients somewhere and will dig
it out to see if there was anything particularly unusual.

Do you have tidal curves for 17/9-21/9 ? I'd be interested to see them.

16/10 also has favourable geometry for a good high tide as well.

--
Regards,
Martin Brown