Forecasting October–November Caribbean hurricane days

[1] October–November Caribbean hurricane activity can have profound impacts on the region through loss of life and devastation of property. Large‐scale climate parameters associated with active late seasons in the Caribbean are investigated in this paper. Among the primary features that are noted are atmospheric and oceanic conditions typical of La Niña and a larger‐than‐normal Atlantic Warm Pool as well as reduced trade wind strength in the western tropical Atlantic. A two‐predictor statistical model has been developed to forecast the number of hurricane days in the Caribbean during October–November. The first predictor is the July–September–averaged Nino 3.4 index, a measure of El Niño‐Southern Oscillation, while the second predictor measures July–September–averaged sea surface temperatures in the western part of the tropical Atlantic extending into the Caribbean, which very closely correlates with the size of the Atlantic Warm Pool. These two predictors can hindcast approximately 58% of the variance in the number of October–November Caribbean hurricane days over the period from 1982 to 2010 when a drop‐one cross validation procedure is applied. The predictors also correlate significantly with physical features in the Caribbean basin that are known to impact tropical cyclones. While these strong correlations between predictors and physical features extend back to an independent period from 1900 to 1981, the correlations between individual predictors and October–November hurricane days degrade considerably during the earlier period.