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Strictly, for different lead times (i.e. for the different coloured curves) the M-climate will vary a little bit (due to model drift and under-sampling) but also more particularly in spring and autumn when day-to-day climatic changes are at their greatest (see Limitations of twice weekly updates to the M-Cimate).   In spite of such variations it is still reasonable, helpful and recommended to inter-compare the M-climate curve (black) with all the coloured curves (even if this is only strictly valid for the same lead time that it represents - i.e. the red curve).  Note, incidentally, that the M-climate, as used here and on 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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