Figure 2 shows their 12 month precipitation forecast on the top half and a map of the accuracy of previous forecasts on the bottom. (drtimball.com)
Zhang Y., L. Wu, M. Scheuerer, J. Schaake and C. Kongoli (November 2017): Comparison of Probabilistic Quantitative Precipitation Forecasts from Two Postprocessing Mechanisms. (esrl.noaa.gov)
The verification of seasonal precipitation forecasts for early warning in Zambia and Malawi. (en.ilmatieteenlaitos.fi)