Forecasts are produced for the north-east part of Brazil between 0° S to 10° S and east of 50° W. The wet season is between February and May with considerable year-to-year and decade-to-decade variability. The forecasts are produced using a combination of dynamical forecast models and statistical predictions and include predictions of the most likely of five rainfall categories (very wet, wet, average, dry or very dry). Each of these categories has occurred in one-fifth of past years. A long-lead forecast is normally issued in December and a final forecast is issued in February for March to May.
Our latest forecast for the 2013 north-east Brazil wet season weakly favours below average rainfall over above average rainfall. For detailed information, see our latest forecast (PDF, 569 kB) .
The final forecast for the 2012 wet season correctly favoured below-average rainfall over the whole region. For more details, see 2012 forecast (PDF, 1 MB) .
The table below compares observed outcomes with our past February-issued forecasts for one typical region. Overall, the correlation between the predicted and observed category is 0.63, which is significantly skilful at the 95% level of statistical confidence.
|Year||Forecast category||Observed category|
|1987||Very Dry||Very Dry|
|1989||Very Wet||Very Wet|
|1990||Dry or Average||Dry|
|1992||Dry or Very Dry||Very Dry|
|1996||Dry or Average||Wet|
|1997||Forecast not issued||Average|
|2007||Dry or Average||Very Dry|
|2009||Very Wet||Very Wet|
|2012||Very Dry||Very Dry|