Jet Streaks |
 Dave Thurlow, Host |
 An illustration of jet-related circulation patternd during snowstorms along the East Coast of the United States. Jet streaks are embedded within confluent and diffluent regions, sea-level isobars are represent by solid lines, and the two pinwheels depict circulations. (From Kocin and Uccellini, 1990.) |
Meteorologists and scientists have long been trying to solve the puzzle of why storms develop where they do, and they have zeroed in on a key piece of that puzzle. What they're looking at are narrow, high-speed bundles of strong wind, about five miles above the ground, called jet streaks.
We've known about jet 'streams' ever since pilots discovered them in World War II. The main polar jet stream winds around the entire globe, while a jet streak is a smaller and more localized. A jet streak is a speeding car darting through traffic where the jet stream is the highway.
Jet streaks are important because they cause air to rise near the ground below. The atmosphere has to adjust to the extra energy delivered by the streak, so air is forced up or down on each side of the jet streak as it comes and goes. These rising and falling air pockets help determine where a storm will form near the ground.
The trick is to find these jet streaks before they do their thing. Weather balloons are too far apart to find every jet streak, but scientists are getting better at reading between the data points. And computers can follow a jet streak several days into the future to see where a storm might blossom.
Now for more graphics and additional information on jet streaks, be sure to visit our website at weathernotebook.org. Thanks to contributing writer Bob Henson. Our show is underwritten by Subaru, with major support provided by the National Science Foundation.