Here's a thread with useful links that I posted on another forum.
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Thankfully, there will not be a storm sturge with these high tides in
September because High Pressure will be over the UK supressing the
height of the tide by a few Centimetres.

http://www.wetterzentrale.de/pics/avnpanel1.html

A rough guide is that a change in pressure of one millibar (one
hectopascal in modern units) will change the sea level by one
centimetre. Tide tables assume a standard pressure of 1013 millibars.
This means that a pressure of 1040 mb, pretty high but not abnormally
so, could give a sea level lower by nearly 30 cms than expected.

http://www.franksingleton.clara.net/...and_tides.html

For an approximate rule of thumb, subtract 1013 from the air pressure,
then subtract the result (in centimetres) from the tide height. For
calculations remember than 'minus minus' is actually 'plus', and 'minus
plus' is 'minus'.

Example #1: Pressure at 1005, minus 1013 equals -8. Subtract this from
a tide of 8.1m, 810cm - (-8cm) = 818cm (8.18m).

Example #2: Pressure at 1025, minus 1013 equals +12. Subtract this from
a tide of 8.3m, 830cm - (+12cm) = 818cm (8.18m).

http://www.wsyc.org.uk/wsyc_pages/ws..._pressure.aspx

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Use the Free Link below, for published tidal predictions in your area,
then adjust the height according to prevailing air pressure on the
forecast date.

http://easytide.ukho.gov.uk/EasyTide...electPort.aspx

These tides are indeed very high. For instance, Teignmouth is
predicted to have a High Tide of 5.3m on the evening of Fri 8th Sept,
the highest tide I can every remember being published for Teignmouth is
5.5m.

http://easytide.ukho.gov.uk/EasyTide...ictionLength=7