What is the jet stream?

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What is the jet stream?
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Jet streams are bands of strong wind that generally blow from west to east all across
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the globe.
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Jet streams form when warm air masses meet cold air masses in the atmosphere.
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Air masses have different temperatures because the Sun doesn’t heat the whole Earth evenly.
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Areas near the equator are hot and areas near the poles are cold.
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The warmer air rises up in the atmosphere while cooler air sinks down to replace it.
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This movement causes an air current.
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These air currents are high in the atmosphere.
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On average, they travel at about 110 miles per hour.
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In the winter, when the temperature differences between warm and cold air masses are more
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dramatic, jet streams can go much faster—250 miles per hour or more.
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No matter the season, the primary jet streams only travel from west to east because of how
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Earth rotates on its axis.
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Jet streams are located in the middle and upper parts of a layer of the atmosphere called
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the troposphere.
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This is the height in the atmosphere where airplanes fly as well.
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That means airplanes can fly in the jet stream, especially when they’re headed in the same
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direction the jet stream is blowing.
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This is why an airplane flying from west to east can make the trip faster than an airplane
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traveling the same route east to west.
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Jet streams can also affect our weather, by impacting temperature and precipitation.
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Some weather systems ride the jet stream across the country.
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Or, if the weather system is far away from a jet stream, it might stay in one place,
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causing a heat wave or a flood.
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Monitoring jet streams can help meteorologists determine where weather systems will move
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next.
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This is important because the path of a jet stream can change quickly, taking storms in
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different directions.
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NOAA’s GOES-R series satellites use infrared radiation to detect water vapor in the atmosphere.
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With this technology, meteorologists can monitor the location and activity of the jet streams.
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The GOES-R series satellites can give up-to-the-minute reports on where jet streams are in the atmosphere—and
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where weather systems might be moving next.
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Find out more about Earth’s weather at NOAA SciJinks.