Which wind system consists of surface winds in Ferrel cells near 45 degrees latitude, blowing from the southwest in the Northern Hemisphere and from the northwest in the Southern Hemisphere?

• A. Trade Winds
• B. Doldrums
• C. Westerlies
• D. Polar Easterlies

Answer: (C)

The Winds here are the Westerlies. In mid-latitudes, surface air moves from the subtropical high around 30° latitude toward the cooler subpolar low near 60° latitude, within the Ferrel cell. The Coriolis force deflects this flow to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, so the air appears to come from the west and spread toward the east. That makes the Northern Hemisphere winds predominantly from the southwest (blowing toward the northeast) and the Southern Hemisphere winds predominantly from the northwest (blowing toward the southeast). These westerly winds drive weather systems from west to east across mid-latitude regions. The other options describe winds in different zones: the Trade Winds are near the equator blowing from east to west, the Doldrums are near the equator with very calm conditions, and the Polar Easterlies occur near the poles blowing from the east toward the west.