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Met Office meteorologists work in one of only two centres in the world that produce weather charts for global aviation. They detail the location, height and strength of forecast jet streams and the turbulence associated with them.
Although the position and height of the jet stream changes, it essentially moves around at a similar level to that of transatlantic aircraft. If you were to fly along the flow of the jet stream it would be quicker and save fuel.
In the winter, areas in the Northern Hemisphere may get colder than in other periods as the jet stream dips "lower," bringing cold air in from the polar regions.
In spring, the polar jet starts to journey north from its winter position along the lower third of the U. As the jet gradually lifts northward, highs and lows are "steered" along its path and across the regions where it's positioned. Why does the jet stream move? Jet streams "follow" the sun, earth's primary source of heat energy. Recall that in spring in the Northern Hemisphere, the sun's vertical rays go from striking the Tropic of Capricorn As these northerly latitudes warm, the jet stream—which occurs near boundaries of cold and warm air masses—must also shift northward to remain at the opposing edge of warm and cool air.
Although the height of the jet stream is typically 20, feet or more, its influences on weather patterns can be substantial. High wind speeds can drive and direct storms, creating devastating droughts and floods. A shift in the jet stream is a suspect in the causes of the Dust Bowl.
On surface maps: Much of the media that broadcast weather forecasts show the jet stream as a moving band of arrows across the U. Here's an easy way to eyeball the jet position: Since it steers high and low pressure systems, simply note where these are located and draw a continuous curved line in between them, taking care to arch your line over highs and underneath lows.
On upper-level maps: The jet stream "lives" at heights of 30, to 40, feet above Earth's surface. At these altitudes, atmospheric pressure equals around to millibars; this is why the and millibar-level upper air charts are typically used for jet stream forecasting. When looking at other upper-level maps, the jet position can be guessed by noting where pressure or wind contours are spaced close together. Climatologists say that changes in the jet streams are closely tied to global warming, especially the polar jet streams, because there is a great deal of evidence that the North and South poles are warming faster than the remainder of the planet.
When the jets streams are warmer, their ups and downs become more extreme, bringing different types of weather to areas that are not accustomed to climate variations.
If the jet stream dips south, for example, it takes the colder air masses with it. Jet streams also have an impact on air travel and are used to determine flight patterns.
That can also cause a bumpy flight, because the jet stream is sometimes unpredictable and can cause sudden movement, even when the weather looks calm and clear. Aeronautics played a role in the discovery and mapping of jet streams. Many credit bomber pilots flying missions during World War II with much of the knowledge we have today about the jet streams. They were able to quicken their missions and beat hasty retreats over the Mediterranean Sea by making the most of the jet streams.
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