FAA Private Pilot Helicopter (PRH)WeatherEasy
In the Northern Hemisphere, a pilot flying near a surface low-pressure system should expect surface winds to circulate in which pattern?
- ACounterclockwise and inward
- BCounterclockwise and outward
- CClockwise and outward
- DClockwise and inward
Show answer & explanationAnswer & explanation
Correct answer: A. Counterclockwise and inward
In the Northern Hemisphere, surface winds around a low-pressure system flow counterclockwise and inward toward the center due to the Coriolis force and pressure gradient force combined with surface friction. Around a high, winds flow clockwise and outward.
Why the other options are wrong
- B. Outward flow (divergence) occurs around highs, not lows.
- C. This describes flow around a high-pressure system, not a low.
- D. Clockwise flow is associated with high-pressure systems, not lows.
Pressure System Wind Circulation
In the Northern Hemisphere, wind circulates counterclockwise and inward around low-pressure centers and clockwise and outward around high-pressure centers.
- Low = counterclockwise, converging, associated with rising air and clouds
- High = clockwise, diverging, associated with sinking air and clear skies
- Reversed in Southern Hemisphere
Memory trick: Low sucks in counterclockwise like a drain; High blows out clockwise like a fan