Sub-Seasonal to seasonal Forecasts

Historically, there has been a clear divide between weather and climate prediction, although both use similar numerical tools. Weather prediction, which is essentially an atmospheric initial condition problem, refers to the prediction of daily weather patterns from a few hours up to about two outlooks. Climate forecasting, which is a boundary condition problem, refers to the prediction of climate fluctuations averaged over a season or beyond. This time-scale separation between weather and climate prediction has caused a division among the weather and climate research communities.

The sub-seasonal to seasonal (S2S) time range - which corresponds to predictions beyond two outlooks but less than a season - fills this gap between weather and climate forecasting and represents a central component for ‘seamless’ weather/climate prediction.