Long range forecasts provide information about atmospheric and oceanic conditions averaged over the next few months. Despite the chaotic nature of the atmosphere, long term predictions rely on a number of components which themselves show variations on long time scales (seasons and years) and, to a certain extent, are predictable. The most important of these components is the ENSO (El Nino Southern Oscillation) cycle. Although ENSO is a coupled ocean-atmosphere phenomenon centred over the tropical Pacific the influence of its fluctuations extends around the world.
Similarly to the medium and extended ranges, the long range forecasts are produced by the IFS coupled ocean-atmosphere model. The model is run forward in time to a range of several months; this is repeated many times, with slight variations to represent uncertainties in
the forecast process, to produce the ensemble forecast.
See detailed documentation of the seasonal forecast.
Depending on who you are, you will be able to access different types of products. The linked charts are only displayed if you have correct access rights for that product. Find out about access to our forecasts.
Long range (seasonal) forecast
Forecasts are produced each month, giving an outlook to seven months ahead. Since November 2011 these have been produced using seasonal forecast System 4.
An experimental annual range forecast is produced 4 times a year.
Spatial maps of model probabilities stratified by terciles. Available parameters are: 2m Temperature, Mean sea level pressure, precipitation, Sea surface temperature, 850 hPa temperature and 500 hPa geopotential.
Charts for the tropical region are available to the public.
Tropical storms maps
Forecast of tropical storm frequency, mean location of tropical storm genesis, Hurricane/Typhoon frequency and Accumulated Cyclone Energy (ACE) valid for a six months period for example: Accumulated Cyclone Energy - Long range forecast
Forecast of Equatorial Pacific sea surface temperature anomalies averaged over NINO 3, NINO 3.4, NINO 4 areas.
EUROSIP Multi-model system
The EUROSIP multi-model seasonal forecasting system consists of a number of independent coupled seasonal forecasting systems integrated into a common framework. From September 2012, the systems include those from ECMWF, the Met Office, Météo-France and NCEP.
For more information see the documentation of the EUROSIP system.
Spatial maps of model probabilities stratified by terciles. Available parameters are: 2m Temperature, Mean sea level pressure, precipitation, Sea surface temperature, 850 hPa temperature and 500 hPa geopotential. Forecast is made available on the 15th of each month.
Forecast of Equatorial Pacific sea surface temperature anomalies averaged over NINO3, NINO3.4 and NINO4 areas from the European multi-model Seasonal to Inter-annual Prediction (EUROSIP) system. Forecast is made available on the 22nd of each month.
Tropical storm forecast
Forecasts of tropical storm frequency and mean location of tropical storm genesis valid for a six months period from the European multi-model Seasonal to Inter-annual Predictions (EUROSIP) system. Note that the tropical storm forecasts are created using data from ECMWF and Meteo France systems only.
Annual range forecast
Forecast of Equatorial Pacific sea surface temperature anomalies averaged over NINO 3, NINO 3.4, NINO 4 areas. Annual forecasts are issued every 3 months.