In a 1998 paper presented to the 14th Conference on Probability and Statistics in the Atmospheric Sciences, the current author presented preliminary results of an experiment to establish the limits of predictability.

The experiment involved verifying a set of quantitative forecasts for Melbourne (Australia) out to 14 days.

There have been considerable advances in Numerical Weather Prediction modelling since then, and also in associated techniques for statistically interpreting the NWP model output.

The purpose of the present paper is to revisit the 1998 work in order to establish current limits of predictability.

The output of the GFS 384-Hour (16 Days) NWP Model, as interpreted by a knowledge based forecasting system, is used to achieve that aim.