• The graphics show a merged dataset of the 3 verification systems that have been used at EMC:

    EMC_verif-global: 2021-present

    NCEP Global NWP Model Verification Package: 2008-2020

    Caplan-Zhu Verification System: 1996-2007


  • Regular and anomalous partial sums are computed for each model (see here). Each model's forecasts are verified using its own analysis as truth. All data are regridded using bilinear interpolation, if needed, to the G002 (2.5x2.5 degree) grid. A 40-year (1959-1998) climatology of the NCEP/NCAR reanalysis is used for computing anomalous partial sums.

  • Verification statistics are computed from the regular and anomalous partial sums. The equations used to calculate the verification statistics can be found here. Statistical signifance is calculated using a student-t test.

  • The NWP models evaluated are: GFS: U.S. NCEP Global Forecast System, FNO: U.S. Navy Fleet Numerical Meteorology and Oceanograpy Center, ECM: European Center for Medium-Range Weather Forecasts, UKM: United Kingdom Met Office, CMC: Canadian Meteorological Center, JMA: Japan Meteorological Agency, CFSR: Legacy GFS used for Climate Forecast System Reanalysis, and CDAS: GFS version used for the NCEP/NCAR Reanalysis Project.


  • The verification regions used are: N. Hemisphere: 20N-80N, S. Hemisphere: 20S-80S, Tropics: 20S-20N.