Atlantic Seasonal Hurricane Frequency. Part II: Forecasting its Variability

Abstract

This is the second of two papers on Atlantic seasonal hurricane activity. It is an extension of Part I, which discussed the association of El Niño and the phases of the stratospheric Quasi-Biennial Oscillation (QBO) of equatorial zonal wind with Atlantic seasonal hurricane variability. It is shown how the addition of regional sea-level pressure data from Caribbean basin meteorological stations can be combined with the more global El Niño and QBO information to form a forecast scheme for Atlantic seasonal hurricane activity. Seasonal forecasts might be issued on 1 June of each year and updated prior to the commencement of the most active part of the hurricane season on 1 August. Although this forecast scheme, of necessity, has been developed on dependent data, the expected forecast skill degradation when applied to independent data sets has been estimated. It appears not to be large enough to significantly negate the rather substantial degree of potential forecast skill that is evident in the developmental data set.