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Each CDF plot displays the latest forecast along with the sub-seasonal range model climate (ER-M-climate) corresponding to it, and also all previous sub-seasonal range ensemble forecasts valid for the same 7-day period. The following percentiles are used to draw both ER-M-climate and ensemble forecast CDFs: 0 (minimum), 1, 2, 5, 10, 25, 50 (median), 75, 90, 95, 98, 99 and 100 (maximum). For the forecasts, which have far fewer realisations than the ER-M-climate, percentiles 0, 1 and 2 all take the same value, as do 98, 99 and 100.

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Note, incidentally, that the ER-M-climate, as used here and on sub-seasonal range meteograms, is now based on re-forecasts initialised from ERA5 data; this is higher quality output, and has greater compatibility with actual forecasts, than was the case previously when the re-forecasts were initialised from ERA-Interim data (i.e. before model cycle 46r1 was introduced in June 2019).

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Extreme Forecast Index (EFI) - sub-seasonal range forecast

These EFI charts aim to point to areas where unusually anomalous temperature or precipitation is likely to occur.

The EFI temperature chart shows the weekly mean EFI for 2 m temperatures.  This is derived from the distribution of ensemble forecast 2 m temperatures compared with the temperature distribution in the ER-M-climate.

The EFI precipitation chart shows the weekly mean EFI for precipitation.  This is derived from the distribution of ensemble forecast precipitation compared with the precipitation distribution in the ER-M-climate.

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.

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See Section 12B for description of the Reliability diagrams and ROC diagrams and interpretation of Cost/Loss diagrams.

(FUG Associated with Cy49r1)

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