Question

What global surface winds blow across mid latitudes in northern hemisphere?

Answer 1

These are the prevailing westerlies or simply the westerlies.

Explanation:

Convection between warm air at the equator and cold air at the poles interacts with the rotation of the Earth to create a fairly complex pattern of winds. We get winds from the east, the trade winds, near the equator and winds from the west, the prevaiing westerlies, at mid-latitudes like the United States or the southern half of South America. See, for example, https://en.wikipedia.org/wiki/Westerlies.