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WINDS & CURRENTS




Winds and Currents

Air always flows from a high pressure to a low pressure. Atmospheric pressures cause convective currents and wind, such as Coriolis force, friction, and changes in temperature in the surface.

Convective currents are the upward and downward motion of air and wind is the horizontal (side-to-side) motion.


Wind patterns

Since we are in the Northern Hemisphere, airflows from a high pressure to a low pressure and is deflected to the right, which cause a clockwise rotation around high pressures.


High-pressure systems are of dry descending air, which is typically good weather.

  • Clockwise motion and anticyclonic circulation.

Low-pressure systems are of ascending or rising air, which is typically bad weather. These systems bring cloudiness and precipitation along with bad weather, which are not uncommon.

  • Counterclockwise motion and cyclonic circulation.


A pilot should have a good understanding of wind patterns associated with high and low-pressure systems when planning a long cross-country flight from west to east or vice-versa.

Flying east to west


When flying from west to east, favorable winds are at the north side of a high pressure or on the south side of a low-pressure system. Whereas on the return flight from the east to back to the west, the favorable winds are on the south side of a high pressure and the north side of a low-pressure.



Convective Currents

Convective currents are the bumpy, turbulent air felt when flying at lower altitudes during warm days. This is caused by rocks, sand, barren land, which gives off more heat. Whereas water, tress and vegetation absorb heat and gives off very little.

Convective currents are more noticeable when flying around landmasses near large bodies of water such as the ocean, large lakes.

The land heats faster than water, causing the air over land to become less dense, this air rises and is replaced with the cooler air from the water.

Pilots should be aware of convective currents near the ground on final approach, which can cause the airplane to balloon and be hard to control.


Effective of Obstructions on Wind

Obstruction on the ground effect the flow of wind and create problems for pilots. Types of obstructions and man-made structures, are:

  • Hangars

  • Large buildings

  • Mountains

  • Bluffs

  • Canyons

This ground obstructions, depending on the size and the speed of the wind can cause turbulence, which can affect takeoff and landing aircraft performance and be seriously hazardous.

Pilots should be aware during the landing phase. The aircraft may “drop in” due to turbulent air on approach to land, causing the airplane to be too low to the ground.

Greater awareness should be considered when flying in mountainous areas. As the wind flows down the leeward side of mountains. The stronger the wind greater the downward pressure and turbulence.



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