Solar Semidiurnal Tide (S2) - animation
This animation of the S2 tide may take a minute or two to load, during which time the frames will refresh one by one. When it is complete you will see the a continuous cycle from high tide (red) through zero (green) to low tide (blue), then back through zero to high tide again.
The S2 tide is strong on the west coast, but quite weak on the east coast. This explains the small spring/neap effect on the east coast.