30 Years of Ensemble Forecasting and Symposium for Prof. Tim Palmer

During the 1970s, the “butterfly effect” or “chaos” was the dominant theme of predictability research, and the community was skeptical about the prospects for dynamical prediction beyond weather. I will give an overview of the evolution of the ideas that lead to the notion of predictability in the midst of chaos and established a scientific basis for dynamical seasonal prediction.

Ever since I met Tim in Liege, Belgium in 1984 for a meeting on Intercomparison of GCM sensitivity to 1982- 83 El Nino SST anomalies, Tim and I have been fellow travelers in our journey through WCRP panels and committees, numerical experimentation groups including coordinated experiments on dynamics and predictability of monsoons, India’s advisory panel on weather and climate forecasting, and the World Modeling Summit. My talk will briefly touch on these topics with renewed commitment to pursue the yet to be realized dream of kilometer scale global climate models. Finally, I’ll also mention briefly a memorable visit by Tim and Gill to the village of my birth in India.