North-east Brazil rainfall

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.

Important

  • Long-range forecasts are unlike weather forecasts for the next few days
  • Forecasts show the likelihood of a range of possible outcomes
  • The most likely outcome in the forecast will not always happen
  • Forecasts are for average conditions over a wide region and time period
  • For more details on interpretation, see How to use our long-range predictions

Forecast

Our latest forecast for the 2014 north-east Brazil wet season favours above-average rainfall over below-average rainfall. For detailed information, see   Updated NE Brazil forecast for MAM 2014 our latest forecast (PDF, 576 kB) .

Verification

The final forecast for the 2013 wet season correctly favoured below-average rainfall over the whole region. For more details on last year's forecast, see Updated NE Brazil rainfall forecast for MAM 2013 final forecast for 2013 (PDF, 569 kB) .

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 0.64, which is statistically significant at the 95% level of confidence.

YearForecast CategoryObserved Category
1987Very DryVery Dry
1988Very WetWet
1989Very WetVery Wet
1990Dry or AverageDry
1991WetWet
1992Dry or Very DryVery Dry
1993DryVery Dry
1994Very WetWet
1995WetVery Wet
1996Dry or AverageWet
1997Forecast not issuedAverage
1998WetVery Dry
1999WetAverage
2000WetAverage
2001AverageDry
2002DryDry
2003Very DryAverage
2004WetVery Dry
2005AverageDry
2006AverageAverage
2007Dry or AverageVery Dry
2008AverageWet
2009Very WetVery Wet
2010DryVery Dry
2011Very WetAverage
2012Very DryVery Dry
2013DryDry

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Last updated: 11 June 2014