Westerlies are the permanent Winds that blow from the tropical high pressure belt to the sub polar low pressure belt in both the hemispheres. They blow from South West to North East . in the northern hemisphere and North West to South East in the southern hemisphere. The velocity of westerlies become so vigorous and fast to be called Roaring Forties at 40° , Furious Fifties at 50° and Screaming Sixties at 60° latitudes.