I Didn’t Know That
Q: How is the exact course of the jet stream plotted?
A: Twice every day, the National Weather Service releases as many as 100 weather balloons that travel as high as 17 miles into the atmosphere, measuring wind direction and speed at different levels. These winds are drawn on constant-pressure maps. The jet stream is evident as a strong core of wind between 20,000 and 30,000 feet, delineated by the strongest winds at those levels. Those winds are often in excess of 100 mph.
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