Can AI weather models predict out-of-distribution gray swan tropical cyclones?

Significance AI models produce skillful weather forecasts, including for some extreme events. However, forecasting the strongest events that are so rare they did not exist in the training set (the so-called gray swans) remains a major concern for these models’ operational use, especially as climate change introduces unprecedented conditions. Here, we train an AI weather model after removing Category 3–5 tropical cyclones from its training set and test it on Category 5 storms. The model could not accurately forecast these unseen cyclones. However, the model shows promise in learning from strong storms in one region and forecasting them in another region. Our work highlights the need for better understanding the limitations of AI weather models and innovations to improve them.