Seasonal forecast is scientifically based approach for providing information on climate characteristics for several months or several seasons ahead. In basic, seasonal forecast has much in common with numerical weather prediction (NWP) in sense that both approaches relay on numerical integration of complex hydrodynamics equations. On the other hand, seasonal forecast’s goal is mainly to predict monthly and seasonal anomalies from long term climatology, rather than to provide a day to day forecasts of weather patterns, as it is the case in NWP. For further reading please visit ECMWF’s page about this topic.
SEEVCCC started to issue seasonal forecast for South East Europe region from June 2009. The system is based on dynamical downscaling of ECMWF seasonal forecast, using a regional atmosphere-ocean coupled model (RCM-SEEVCCC). The forecast consists of 41 ensemble members and is issued ones per month between 15th and 20th of a current month. The forecast run is for 7 months. Horizontal resolution is 0.25 degrees for atmospheric model and 0.2 degrees for the ocean model. Atmosphere is resolved with 32 and ocean with 21 vertical levels. The connection between the two components is through a coupler that performs the exchange of atmospheric surface fluxes and SST after every atmospheric physical time step. Exchanged fluxes are calculated using the atmospheric component and are used directly, without any additional parametrization.