The daily AAO indices are shown for the previous 120 days, and the ensemble forecasts of the daily AAO index at selected lead times are appended onto the time series. The indices are standardized by standard deviation of the observed monthly AAO index from 1979-2000. A 3-day running mean is applied to the forecast time series.

The values at the upper left and right corners of each figure indicate the mean value of the AAO index and the correlation coefficients between the observations and the forecasts, respectively.

The first panel shows the observed AAO index (black line) plus forecasted AAO indices from each of the 11 MRF ensemble members starting from the last day of the observations (red lines).

The ensemble mean forecasts of the AAO index are obtained by averaging the 11 MRF ensemble members (blue lines), and the observed AAO index (black line) is superimposed on each panel for comparison. For the forecasted indices (lower 3 panels), the yellow shading shows the ensemble mean plus and minus one standard deviation among the ensemble members, while the upper and lower red lines show the range of the forecasted indices, respectively.

• Time series of the difference between 15-day running mean values of the observation and the outlooks