Daily values of anomaly correlations for forecasts of 500-hPa heights verifying
during the last 1-2 mos. for forecast lengths of 2,3,4,5,6 and 7 days for 20-80 deg N
(top) and 20-80 deg S (bottom). Each of four panels corresponds to different ranges
of zonal wave number. Forecast length indicated by color of markers.