<p>Although not 100% sure, after some additional searches, I think the answer is the law of inertia. If one throws a ball from at the equator to the north pole, the ball also moves to the right even if one did not intend to do so. The same effect we see when one throws a ball from a moving car (<a href="https://www.youtube.com/watch?v=-VJzr_aSSE4" rel="nofollow noreferrer">example</a>). </p>

<p>The speed is faster near the equator. Therefore, even through Coriolis effect is working, the law of inertia overrules the effect. That is, the movement (to right) of the ball is faster than the rotation of the earth. </p>

<p>Regardless of from north to south, or south to north, Coriolis effect and the law of inertia work in opposite directions. Stronger one determines the direction.</p>

CC BY-SA 3.0
2017-09-19T05:31:39.050Z
2017-09-19T05:31:39.050Z
quibble
<p>Prevailing winds are generated by Coriolis effects. </p>

<p>I think I understand why NE winds are the prevailing winds in 0 to 30 degrees and 60 to 90 degrees latitude in the northern hemisphere (e.g., according to the picture below). But I don't understand why westeries are the prevailing winds in 30 to 60 degrees. If one throws a ball from a point at the equator to the north pole, shouldn't it deflected to the opposite direction by the direction of the rotation of the earth (i.e., creates SE winds)?</p>

<p><a href="https://i.sstatic.net/Fq1cj.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Fq1cj.jpg" alt="Coriolis effect"></a></p>

CC BY-SA 3.0
2017-09-19T01:59:04.580Z
"Prevailing winds are generated by Coriolis effects."  Not true for many places.  Prevailing winds are a function of many factors.  see https://en.wikipedia.org/wiki/Prevailing_winds
f.thorpe
CC BY-SA 3.0
2017-09-19T04:01:40.057Z
a good excuse to study wind rose pictures and pages: https://www.google.fr/search?q=wind+rose&num=100&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjp-cjErrDWAhWMblAKHalxBYQQ_AUICigB&biw=1024&bih=634
bandybabboon
CC BY-SA 3.0
2017-09-19T10:04:45.480Z
The topic of the answer is atmospheric general circulation theory.
Communisty
CC BY-SA 3.0
2017-09-19T13:15:51.980Z
Also related: [What is the cause of the jet streams](https://earthscience.stackexchange.com/questions/321/what-is-the-cause-of-the-jet-streams), [Why is Egypt so dry](https://earthscience.stackexchange.com/questions/8518/why-is-egypt-so-dry), and [What factors determine the number of Hadley cells for a planet](https://earthscience.stackexchange.com/questions/992/what-factors-determine-the-number-of-hadley-cells-for-a-planet).
David Hammen
<atmosphere><wind><ecology>
Prevailing winds between 30 to 60 degrees latitude
quibble
# Prevailing winds between 30 to 60 degrees latitude

(Asked by: username_0 on 2017-09-19)

Prevailing winds are generated by Coriolis effects.

I think I understand why NE winds are the prevailing winds in 0 to 30 degrees and 60 to 90 degrees latitude in the northern hemisphere (e.g., according to the picture below). But I don't understand why westeries are the prevailing winds in 30 to 60 degrees. If one throws a ball from a point at the equator to the north pole, shouldn't it deflected to the opposite direction by the direction of the rotation of the earth (i.e., creates SE winds)?

[![Coriolis effect](https://i.sstatic.net/Fq1cj.jpg)](https://i.sstatic.net/Fq1cj.jpg)

**Tags:** atmosphere, wind, ecology

> **Comments:**
> **username_1**: "Prevailing winds are generated by Coriolis effects."  Not true for many places.  Prevailing winds are a function of many factors.  see https://en.wikipedia.org/wiki/Prevailing_winds  
> **username_2**: a good excuse to study wind rose pictures and pages: https://www.google.fr/search?q=wind+rose&num=100&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjp-cjErrDWAhWMblAKHalxBYQQ_AUICigB&biw=1024&bih=634  
> **username_3**: The topic of the answer is atmospheric general circulation theory.  
> **username_4**: Also related: [What is the cause of the jet streams](https://earthscience.stackexchange.com/questions/321/what-is-the-cause-of-the-jet-streams), [Why is Egypt so dry](https://earthscience.stackexchange.com/questions/8518/why-is-egypt-so-dry), and [What factors determine the number of Hadley cells for a planet](https://earthscience.stackexchange.com/questions/992/what-factors-determine-the-number-of-hadley-cells-for-a-planet).  

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## 1 answers

### Answer by username_0 on 2017-09-19. Score: -2 | Accepted answer

Although not 100% sure, after some additional searches, I think the answer is the law of inertia. If one throws a ball from at the equator to the north pole, the ball also moves to the right even if one did not intend to do so. The same effect we see when one throws a ball from a moving car ([example](https://www.youtube.com/watch?v=-VJzr_aSSE4)).

The speed is faster near the equator. Therefore, even through Coriolis effect is working, the law of inertia overrules the effect. That is, the movement (to right) of the ball is faster than the rotation of the earth.

Regardless of from north to south, or south to north, Coriolis effect and the law of inertia work in opposite directions. Stronger one determines the direction.


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