Get Tidal Prediction Form

The terms of the equation, h = Ho + Sum{ƒH cos[at + (Vo+u) - K]} , are defined as follows: h = height of tide at any time t. Ho = mean height of water level above datum used for prediction. H = mean amplitude of any constituent A.

At most places on earth, there are two high tides each day. With each passing day, the high tides occur about an hour later. The moon rises about an hour later each day, too (actually, 54 minutes later).

This occurs because the moon revolves around the Earth in the same direction that the Earth is rotating on its axis. Therefore, it takes the Earth an extra 50 minutes to “catch up” to the moon.

NOAA Tide Predictions allows users of the Tides and Currents website (http://tidesandcurrents.noaa.gov) to generate tide predictions for up to 2 years in the past or future, at any of 3000+ locations around the United States.

In the classical and simplest scenario, tidal prediction is based on harmonic analysis of past measurements at a fixed location. Limits to predictability arise because isolated astronomical spectral lines are broadened into “cusps” of incoherent energy, for example through interactions with non-tidal flows.

Tides can be predicted far in advance and with a high degree of accuracy. Tides are forced by the orbital relationships between the Earth, the moon and the Sun. These relationships are very well understood and the position of the celestial bodies can be forecast very accurately into the future.

In most cases, local winds and atmospheric pressure variations are the primary causes of the difference between the actual and predicted tide.

Tides are the periodic rise and fall of surface water caused by the gravitational force of the moon and the sun and by the rotation of the earth. The movements of the solar system that influence the tides are predictable; therefore changes in tide height and time are predictable.