Fig 3a. Anomaly correlations for 500-hPa geopotential,forecast days 0-5, latitudes 20-80 N, operational system (MRF, solid lines) versus new system (X, dashed lines). The results are averaged for forecasts verifying over the period 2 March through 1 June 1997 with 92 cases for the MRF and 89 cases for the X. Four zonal wave number groups are shown. Each model is verified against its own analysis.