Cyclonic flow around a low-pressure system in the Northern Hemisphere is...

• A. Clockwise.
• B. Counterclockwise.
• C. No rotation.
• D. Upward flow only.

Answer: (B)

Air moves toward a low-pressure center and, because moving air is deflected to the right in the Northern Hemisphere by the Coriolis effect, this inward flow curls into a counterclockwise rotation. That swirling, cyclonic pattern is the signature of a low-pressure system in this hemisphere, with air converging at the surface and rising near the center. The option describing clockwise rotation would correspond to a high-pressure system, not a low one, so it doesn’t fit. Saying there is no rotation ignores the characteristic swirl, and claiming only upward flow omits the spinning horizontal wind pattern that accompanies the rising air at the center. The key idea is the counterclockwise, cyclonic flow around a Northern Hemisphere low.