The WWRP/THORPEX-WCRP Subseasonal to Seasonal Prediction Project

Many decisions in disaster risk reduction, agriculture, water and health fall in the subseasonal to seasonal (S2S) range. This time scale has been considered a “predictability desert”, and received less work than medium-range and seasonal prediction. The goal of a new WWRP/THORPEX-WCRP joint research project is to improve forecasts and understanding on the S2S scale with special emphasis on high-impact weather events, and promote uptake by operational centers and use by the applications community.

Recent research has indicated important potential sources of predictability through better representation of atmospheric phenomena such as the Madden Julian Oscillation (MJO) and improved coupling with, and initialisation of, the land-ocean-cryosphere and stratosphere. This paper will describe the main research goals and planned implementation of the S2S project, including the establishment of a multi-model data base consisting of ensembles of subseasonal (up to 60 days) forecasts and supplemented with an extensive set of reforecasts following the TIGGE protocols.