AI weather models can now beat the best traditional forecasts

A new machine-learning weather prediction model called GenCast can outperform the best traditional forecasting systems in at least some situations, according to a paper by Google DeepMind researchers published last month in Nature. Using a diffusion model approach similar to artificial intelligence (AI) image generators, the system generates multiple forecasts to capture the complex behaviour of the atmosphere. It does so with a fraction of the time and computing resources required for traditional approaches. The weather predictions we use in practice are produced by running multiple numerical simulations of the atmosphere. Each simulation starts from a slightly different estimate of the current weather.