Bermuda High

The name given to the high-pressure anticyclone that dominates wind patterns over the North Atlantic Ocean. Influenced by the progression of the seasons, the clockwise-spinning Bermuda High serves to determine the tracks or trajectories of Atlantic hurricanes as they move westward across the ocean’s subtropical reaches. During the winter months when air and water temperatures in the Northern Hemisphere are low, the Bermuda High is relatively small and is positioned in the ocean’s southeast quadrant. But during the summer months of July through September when water temperatures in the region are much warmer, the Bermuda High strengthens considerably, growing to encompass the entire center of the North Atlantic. In this position it influences a host of meteorological factors, including the steering currents of hurricanes. Because the Bermuda High is an area of settled high-pressure,low-pressure tropical cyclones cannot encroach upon it. 

Instead, they must either progress along its southernmost flank and undergo recurvature as they round the anticyclone’s western edge, or else move up from the Caribbean Sea and continue with the northeasterly curl until it guides them into the North Atlantic’s cooling spaces. If during a particular season the Bermuda High is of notably large size and is situated farther to the west than is normal, that year’s crop of hurricanes will be more likely to make landfall in the Gulf of Mexico or the United States’s eastern shores. Conversely, if the Bermuda High is less intense than usual, a number of Atlantic hurricanes can find their way to the west coast of Europe. Such an occurrence was seen during the 1966 hurricane season, when Hurricane Faith brought 100-MPH (161-km/h) winds to Norway, and during the 1987 season, when tropical storm Arlene delivered flooding rains to Portugal.