Evaluation of ECMWF forecasts, including the 2021 upgrade

The most recent change to the ECMWF forecasting system (IFS Cycle 47r2, on 11 May 2021) is summarised in section 2. The description of changes and meteorological impacts from this upgrade largely follows the ECMWF Newsletter article of Rodwell et al. (2021). Verification results of the ECMWF medium-range upper-air forecasts are presented in section 3, including, where available, a comparison of ECMWF’s forecast performance with that of other global forecasting centres. Section 4 presents the verification of ECMWF forecasts of weather parameters and ocean waves, while severe weather is addressed in section 5. Finally, section 6 discusses the performance of monthly and seasonal forecast products.
As in previous reports a wide range of verification results is included and, to aid comparison from year to year, the set of additional verification scores shown here is consistent with that of previous years (ECMWF Tech. Memos. 346, 414, 432, 463, 501, 504, 547, 578, 606, 635, 654, 688, 710, 765, 792, 817, 831, 853, 880). A few new plots have been included to highlight additional aspects of ECMWF’s forecast performance. A short technical note describing the scores used in this report is given at the end of this document.
Verification pages are regularly updated, and accessible at the following address:
www.ecmwf.int/en/forecasts/charts
by choosing ‘Verification’ under the following headers
• ‘Medium Range’ (medium-range and ocean waves)
• ‘Extended Range’ (monthly)
• ‘Long Range’ (seasonal)