You’ve heard meteorologist talk about jet streams all the time. But have you ever wondered what they are exactly?
Meteorologists talk about jet streams for a good reason. They can actually influence everything about our weather and impact our daily lives.
Jet streams are narrow bands of strong winds that flow from west to east, and they reside at around 30,000 feet in our atmosphere.
(NOAA)
There are two things that cause them: the Earth’s rotation and temperatures.
The Earth moves at different speeds at different locations, causing the Coriolis effect, and the Sun heats the Earth unevenly because of Earth’s tilt.
The Coriolis effect and uneven heating result in three circulations in each hemisphere.
(NOAA)
In between these circulations is where the temperature changes are greatest, which causes the wind to increase and creates the jet streams.
(NOAA)
The jet streams aren’t uniform at all times. Changes in pressure and temperature can cause them to move north and south, split and even disappear.
The change in season can also “move” jet streams. As the Sun’s elevation increases in the warmer months, jet streams will shift more poleward. As it decreases in the colder months, jet streams will move toward the equator.
Why jet streams matter
The first big reason jet streams are important is because they help move weather systems across the country.
This can affect the temperatures we get or how much precipitation we see. If a system gets detached from a jet stream, it can stall out in an area. This can lead to flooding if it’s a storm system stalling out, or it can lead to heat waves and dry weather if high pressure is in place.
Also, if the jet stream is far south, we see more extreme weather because warmer, moist air meets up with Arctic air. This allows the air to rise more quickly, creating more storms.
The second reason jet streams are important is because they can cut down our time when flying.
Airplanes fly at the same height as jet streams, so when flying from west to east, airplanes can get a little boost with their speed. But when flying from east to west, you won’t see much improvement with time.
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