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Seasonal output - chart format

The long-range graphical The seasonal graphical products do not show absolute values, but instead highlight differences between the forecasts and the Seasonal seasonal climate (S-M-climate).  When "probabilities" are provided, these denote the proportion of ensemble members that predict a certain type of outcome.  Thus if 35 members of a 50 member ensemble predict the 2m temperature to exceed the mean in the S-M-Climate, then the "probability" is taken as 70%.

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Explanation of Terciles and Quintiles

In SEAS5seasonal forecasts, anomalies are evaluated relative to 1993-2016 model climate (shorter S-M-climate), both for consistency with Copernicus C3S and because anomalies relative to a more recent “past” are likely to be more relevant to most users.  However, the re-forecasts are also produced from 1981-2016 (longer S-M-climate). This period is the basis of the verification charts provided online, and also allows users to explore the choice of different reference and calibration periods.

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