Subseasonal Prediction of Extreme Weather Events

Prediction of extreme weather events two-to-six weeks ahead has immense social-economic benefits for hazard prevention and risk management as well as economic planning. Physical basis for such subseasonal prediction is primarily rooted in the intrinsic predictability of large-scale circulation associated with the tropical intraseasonal oscillation (ISO). Such prediction requires not only accurate prediction of tropical ISO and its teleconnection, but also the knowledge of how ISO modulates extreme weather events in the tropics and extratropics. This chapter provides a review of current knowledge on the modulation of ISO on many types of extreme weathers in the global tropics and extratropics including flooding, heavy snow storms, cold surges, hurricane and tropical storms, wild fire, aerosols, tornado and hail days, etc. This type of knowledge affords useful prediction tools for subseasonal prediction of extreme events if provided ISO can be realistically forecasted. Recent progress on subseasonal forecasts of tropical storm activity made by world major operational centers is also briefly reviewed and issues are discussed.