What is jet stream

You've probably heard the term "jet stream" many times while watching weather forecasts on television. That's because the jet stream and its location is key to forecasting where weather systems will travel. Without it, there would be nothing to help "steer" our daily weather from location to location. Additionally, jet stream often house pockets of winds that move faster than the surrounding jet stream winds. These "jet streaks" play an important role in precipitation and storm formation: If a jet streak is visually divided into fourths, like a pie, its left-front and right-rear quadrants are the most favorable for precipitation and storm development. If a weak Jet winds blow from west to east, but also meander north to south in a wave-shaped pattern. These waves and large ripples—known as planetary waves or Rossby waves—form U-shaped troughs of low pressure that allow cold air to spill southward as well as upside-down U-shaped ridges of high pressure that bring warm air northward. • The polar jet: In North America, the polar jet is more commonly known as "the jet" or the "mid-latitude jet," so-called because it occurs over the mid-latitudes. • The subtropical jet: The subtropical jet is named for its existence at 30 degrees north and 30 degrees south latitude—a climate zone known as the subtropics. It forms at the boundary of the temperature difference between air at mid-latitudes and warmer air near the equator. Unlike the polar jet, the subtropical jet is only present i...

Sign up to receive our latest reporting on climate change, energy and environmental justice, sent directly to your inbox. Subscribe here. The jet stream—a powerful river of wind high in the atmosphere—shapes the Northern Hemisphere’s weather, including bitter cold snaps. Because it plays a key role in weather extremes, climate scientists are striving to understand its changing dynamics. Here’s a closer look at what the jet stream is, what’s influencing its wobbly behavior and why it matters. First things first: What is the jet stream? The jet stream races from west to east at speeds up to 275 miles an hour, undulating north and south as it goes. This powerful river of wind transports moisture and moves masses of cold and warm air and storm systems along its path. During the hurricane season, it sometimes helps push Atlantic tropical storms away from the East Coast. The northern polar jet stream (it has a counterpart in the Southern Hemisphere) is driven partly by the temperature contrast between masses of icy air over the North Pole and warmer air near the equator. Climate change, true to the predictions of the past half century, has led to faster warming in the Arctic than in the temperate zones. So the temperature difference between the two regions has been lessening. Research suggests that this reduction in the temperature difference is robbing the jet stream of some of its strength, making it wobblier and contributing to more temperature extremes. What’s the jet stream...

" " Multiple jet contrails crisscross the sky above Red Rock Canyon National Conservation Area near Summerlin, Nevada. George Rose/Getty Images The trail of clouds that billow from an Before we get into the various theories about the possible harmful effects of these contrails, let's first discuss the scientific explanation for these trails. Jet engines spew out very hot air, and because water vapor is also one of the byproducts of the exhaust, the air is also very humid [source: vapor pressure, or the force exerted by a gas on the surrounding environment. When a jet engine is emitting out hot, humid air into an atmosphere that is so cold and has low vapor pressure, the result is condensation. The water vapor coming out of the engine quickly condenses into water droplets and then crystallizes into ice. The ice crystals are the contrails, short for "condensation trails." To help explain it, scientists liken it to seeing your breath on cold days. You may have noticed that puffs of breath dissipate quickly on drier days. The same is true of contrails: When the atmosphere is more humid, the contrails linger longer, but when the atmosphere is dry, the contrails disappear more quickly. Contrails can last for hours and cover great distances [source: This explanation makes sense. But, as author and airline pilot Patrick Smith wrote, the contrails consist of not just ice crystals and water vapor, but also of other byproducts of engine exhaust, including chemtrails" because they sus...