Super Spring tides?

[squidge]

Hi ,with the longest day just passed and the moon in a position which it only gets to in 19 years what effect is this going to have on the tides?
Checking the tidal graph for this w/e its very close to the lowest possible but its not the highest(bbc tide for burnham).
Can they get Lower than the chart data?
thanks
rgds

 

[Evadne]

They can get lower than datum, or LAT (lowest astronomical tide), especially if there is a high pressure system overhead. But not by much. In the Solent a good rule of thumb is that the closer to 12:00/00:00 BST that HW is, the "springier" it is. I'm not sure what time of day that translates to on the East coast, though.

 

[Das_Boot]

We have already had a couple of boats stuck in the channel exiting the marina. Perhaps the extra low tide has caught them out rather than as we all beleived their low IQ.

 

[Phoenix of Hamble]

East coast is approx 2 hrs after you guys....

 

[squidge]

It looks like we will get to see more of the sand banks than usual , i will have to make sure that i dont see then to closely. /forums/images/graemlins/crazy.gif

 

[andy_wilson]

Yes. LAT plus offshore winds plus high pressure system = lower than Lowest Astronomical Tide

Other local factors are usually notified as and when by navigational warnings.

 

[gandy]

Aren't the biggest tides at the Equinox, not the Solstice?

Tony S

 

[bilbobaggins]

Oh, yes. You will see, if you scrute your BA charts carefully, that the tidal height predictions are ( usually ) in respect of Lowest Astronomic Tide ( LAT ). At its simplest, this reflects a calculation which includes only the gravitation and consequent harmonic effects of the sun, moon and other heavenly bodies.

Atmospheric pressure ( High and Low ) and wind strength/direction/duration also have their effects, which can - at times of extreme Spring Low Water - reduce the actual height of tide below that predicted, and below LAT.

For a good, reasonably full explanation which is still comprehensible, see Michael Reeves-Fowkes' Tidal Atlas ( encompassing his 4 or 5 regional Tidal Stream Atlases )