Where are the Roaring Forties?

Roaring forties - are westerly winds found between latitudes 40º and 60º South. They are prevailing winds resulting from the large planetary circulation of the atmosphere. The prevailing westerlies occur in both hemispheres in the middle latitudes (30º - 60º) but in the Northern Hemisphere the great continental land masses of North America and Asia create a disturbance to the regular wind pattern and it is only in the Southern Hemisphere with its small land masses that these westerlies sweep unimpeded across the Southern oceans. Intense blustering cold and often stormy these winds were given their name by sailors who in the days of sail made the outward voyage to Australia by way of the Cape of Good Hope at Africa's southern tip and the return passage via Cape Horn the southernmost tip of South America. In this way sailing vessels would have the advantage of a following wind for both passages.