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.friction3.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

appearance to the observer on Earth of the path of a moving object to deflect to the right in N. right in N. Hemisphere Hemisphere & to the left in the S. left in the S. HemisphereHemisphere

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

http://www.uwf.edu/atc/projects/coriolis/main.swf