Solar Cycle Extremes as a Seasonal Predictor of Atlantic-Basin Tropical Cyclones

The solar cycle (quantified by sunspot number) has been suggested to be a contributing factor in tropical cyclone frequency and/or intensity, with an active sun (more sunspots) causing heightened activity. Here we analyze the relationship between North Atlantic tropical cyclones and extreme minimum and maximum sunspot years. Sunspot numbers are tested with other common predictors to determine their utility in seasonal tropical cyclone prediction. It is found that the complete sunspot cycle is not consistently related to basin-wide tropical cyclone activity (r = 0.024). However, sunspot extreme years show stronger correlations, with minimum years having the highest correlations to tropical cyclone frequency. Minimum sunspot years and the AMO index can combine to explain more than 54 percent of the variations in total tropical cyclones and nearly 46 percent of the variation in tropical cyclone days. Solar cycle extremes should be considered for more accurate seasonal tropical cyclone predictions.