The CPT is a tool for climate prediction using statistical methods. This tool was developed by IRI. Its a good tool.

I know of another tool that is as practical and simple to make seasonal forecast.

Excuse me...

I do not know another tool that is as practical and simple to make seasonal forecast.

The CPT uses some methods well known to prognóasticos. The canonical correlation analysis (CCA) is the most used. The quality of the forecasts will depend on several factors: region, predictor of type (sst is the most used), data quality (eg rain), size of data sets, etc ...

In some cases estatísicas forecasts may have better ability than the dynamic models.

The INMET (National Meteorological Institute) in Brazil makes statistical predictions (CCA) with the CPT and has good results (do not exist great statistical or dynamical models).

http://www.inmet.gov.br/portal/index.php?r=clima/prev_estocastica

http://www.inmet.gov.br/portal/index.php?r=clima/previsao_sazonal