A simplified early August Atlantic basin seasonal hurricane prediction scheme

The Tropical Meteorology Project at Colorado State University has issued seasonal forecasts for Atlantic basin hurricane activity in early August since 1984. This study examines a simplified scheme, using a combination of two surface predictors selected from the newly-developed Climate Forecast System Reanalysis (CFSR) as well as a dynamical forecast for El Niño-Southern Oscillation (ENSO) from the European Centre for Medium-Range Weather Forecasts (ECMWF). These three predictors in combination explain approximately 72% of the cross-validated variance in post-1 August Net Tropical Cyclone (NTC) activity over the hindcast period from 1982-2010. While uncertainties in the data grow as one goes back further in time, all three predictor correlations remain significant with NTC when tested on data from 1900-1981. These predictors are also shown to correlate with August-October physical features across the Atlantic Main Development region known to impact hurricane activity.