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Charts available are: 2m temperature, surface temperature, total precipitation, mean sea level pressure, winds. 

Colouring on the charts is implies >90% significance for the anomaly.  This does not mean the white shading on the maps necessarily points to:

• a forecast of average.
• a 'don't know' forecast of climatology.

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• The chart displays the probability of the forecast anomaly lying in the upper half of the ER-M-climate distribution (i.e. above normal; warmer or wetter etc than the mean of the ER-M-climate). 

White on the plot means that either:

• the proportion of members above the ER-M-climate mean is between 40% and 60%,
• or that that proportion, whatever it is, is not statistically significant.

This plot structure circumvents the fact that some ER-M-Climate distributions will be skewed (i.e. the climatological probability of seeing more than the mean is far from 50%).can currently signify a number of different things - e.g. median of the forecast is about the same as the median of the re-forecasts. This fact that there are several potential interpretations can be confusing for users and ECMWF plans to offer improved products to address this later in 2024. 

Note: On precipitation charts the range of colours available for "below average" anomalies (brown colours) is constrained by the local climatology in the ER-M-climate.  For example if all ENS members showed a dry week, the mean (-ve) anomaly could be no larger in magnitude than the mean in the ER-M-climate.  So in some locations the strongest dry signal one can ever see will only be in the first or the second of the brown shades.

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Click on the central small icon in the bottom right of the web frame to show the colour scale of values appropriate to each display.

Any pixel that has high probability for lower (or upper) decile should have at least the same or higher probability for lower (upper) quintile and even higher for lower (upper) tercile.  On occasion this has not happened and is being investigated.

Multiparameter outlook - Extended range forecast

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Click on the central small icon in the bottom right of the web frame to show the colour scale of values appropriate to each display.

Any pixel that has high probability for lower (or upper) decile should have at least the same or higher probability for lower (upper) quintile and even higher for the tercile. 

Measures of skill of forecasts. 

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