What causes the prevailing westerlies?
These prevailing winds stream eternally across the wide temperate belt of North America. Vancouver and its majestic island stand directly in their path. All year long, they blow and buffet from the Pacific toward the Atlantic, bearing along alternate pockets of balmy and stormy weather. All the world’s prevailing winds are performing a breezy hoedown on a global scale. In each hemisphere, they girdle the globe in three belts meanwhile swooping in and out of upstairs and downstairs wind systems. Our downstairs westerlies are merely one part of all this activity, emerging from one swerve and sweeping on to the next. Before we place them in the planetary picture, let’s fix some directions on our fingertips. West winds blow from west to east, north winds blow south from the north. A wind is named from where it comes. When blowing south, a right turn veers it westward to become an east wind. When blowing north, a right turn changes it into a westerly wind. Our dizzy planet spins eastward, i
