The extended-range forecast provide an overview of the forecast for the coming 46 days, focusing mainly on the week-to-week changes in the weather.
The graphical products (also referred to as charts or maps) generally present the 32-day forecast in terms of anomalies relative to climate (for example showing if the weather is likely to be warmer or colder than average for the time of year), and are mainly shown as 7-day means (for calendar weeks Monday-Sunday). They are derived from the ENS which is extended twice a week (on Thursday and Monday) to run to 46 days ahead.
As with the medium-range forecasts, specialised products for the extended-range include information on the potential tropical cyclone activity in the coming month. An important source of predictability on the monthly time scale is the Madden-Julian Oscillation (MJO), characterized by an eastward propagation of convection in the tropics, typically initiated over the Indian Ocean. We have specific products to monitor and forecast MJO activity.
See items in this section for more information.