Time series of seasonal mean anomaly correlations of 500-hPa heights for GFS,ECMWF,UKMO,FNMOC,Canada and the CDAS frozen model from 1985 to present. Seasons are three-month non-overlapping averages, Mar-Apr-May etc. Northern Hemisphere(1st four panels), Southern Hemisphere(next four). Shaded bars are differences, GFS minus the indicated model.