It may be NW-SE, SW-NE, or just W-E, but it’s almost always this way. Why not E-W?
In: 10
The reason that they most often move from west to east is due to the jet stream. The jet stream is a narrow band of fast, flowing air currents located near the altitude of the tropopause that flow from west to east.
[deleted]
[removed]
In between the 30 and 60 degree latitudes (includes most of the US), the dominant winds are from the West towards the East, so the storms (and other meteorological structures follow that). The 30 and 60 degrees are averages, it can be sometime higher or lower.
Below the 30 degrees and above 60 degrees, the dominant winds are in the opposite direction. Higher than 60 degrees, there is one permanent vortex which is typically centered on the pole. Below 30 degrees, storms go towards the East because of the dominant winds.
Big storms (hurricanes for example) go towards the poles because of the Coriolis force. Smaller storms tend to still go towards the pole most of the time, but can go towards the equator sometime.
There are dominant, “global” wind patterns on the earth due to hot air rising at the warmer regions and sinking at cooler ones.
This creates a general trend for wind to rise or sink based on latitude. here is a website that lets you explore weather data in a nice visual:
[https://earth.nullschool.net/#2022/05/11/2100Z/wind/surface/level/orthographic=-163.06,12.90,651](https://earth.nullschool.net/#2022/05/11/2100Z/wind/surface/level/orthographic=-163.06,12.90,651)
The link i gave shows the pacific, you can drag around. Using the ‘earth’ label in the lower left you can navigate to different days, features, altitudes (by changing the pressure..lower pressure is higher altitude) etc.
But before you do that, notice how the winds over the equator over the entire pacific are going west. This happens all year with only a few short term exceptions. Up north of hawaii it’s a bit less uniform, but you get a lot of wind heading east, again…all year long.
This is because at the 30-40 latitude lines the hot air from the air tends to sink, and this sinking motion interacts with the rotating earth to deflect east. The rising air at the equator tends to be deflected west. This is all due to conservation of angular momentum.
Prevailing winds across North America are, broadly, always blowing west to east. The storms follow those winds.
Latest Answers