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Wavegram output on ecCharts

Wavegrams are also available to show a time series of significant wave height, mean wave direction, and mean wave period for any sea location.

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Fig22.Q:  Chart showing forecast significant wave heights for several ranges of wave periods (Blue,10-12s; Green, 12-14s; Yellow,14-17s; Red,17-21s).  Forecast data based on data time 00UTC 25 October 2017.  The faster southward propagation of the long period waves over the shorter period waves from their source off NW Africa is clear.

The Extreme Forecast Index (EFI) can be used to indicate the significance of forecast significant wave heights when compared with the range of wave heights that might usually be expected as defined by the M-climate. 

Fig22.R: In this example the colours west of Ireland denote a low-point in wave heights, or potentially a form of 'weather window' for certain types of marine/shipping operations.  Equally this EFI can signify periods with anomalously big waves (yellow to red shading).

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