Meteorological effects on tides
Meteorological conditions which differ significantly from the seasonal averages, will cause corresponding differences between the predicted and the actual tide.
Variations in tidal heights are mainly caused by strong or prolonged winds and by unusually high or low barometric pressure. Tidal predictions are computed for average barometric pressure.
Low pressure systems tend to raise sea levels and high pressure systems tend to lower them. However the water does not adjust itself immediately to a change of pressure but it responds to the average change in pressure over a considerable area.
The effect of wind on sea level, and therefore on tidal heights and times, is variable and depends on the topography of the area in question. In general, it can be said that wind will raise the sea level in the direction towards which it is blowing.
A strong wind blowing straight onshore will cause the water to 'pile up' resulting in high waters to be higher than predicted. Winds blowing off the land will have the reverse effect.