There are 3 major forces that determine how strongly the wind will blow and in what direction: 1. Pressure Gradient Force ◦ push from high pressure to low pressure 2. friction 3. Coriolis effect

 named for, nineteenth century French engineer Gaspard C. Coriolis  Coriolis discovered that a force appears to be operating on any moving object situated on a rotating body, such as a stream of air traveling on the surface of a rotating planet.

 caused by Earth’s rotation right in N. Hemisphere left in the S. Hemisphere  appearance to the observer on Earth of the path of a moving object to deflect to the right in N. Hemisphere & to the left in the S. Hemisphere

 also causes low pressure systems to rotate clockwise  high pressure systems to rotate counterclockwise

 Degree of deflection depends on how fast the winds are blowing and it’s latitude: ◦ slower the wind speed, the less it will be deflected ◦ faster the wind speed, the more it will be deflected ◦ more deflection at the poles ◦ less deflection at the equator

 From outer space it would appear the winds are moving in a straight line  Since you are on earth and it is rotating, it looks to you like the winds are curving  There really a change in motion, but that is ONLY because the target or frame of reference is rotating with the earth

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