Television weathercasts are often not complete without an arrow or two indicating the position of the "jet stream". What are jet streams?
Prior to World War II little was known of atmospheric conditions above the Earth's surface. A few instrumented airplane and kite measurements had been made but cloud patterns proved the most complete guide. Combatants during the war first encountered high speed winds at great altitudes on bombing missions. Reid Bryson, a wartime meteorologist on Saipan in the Pacific in November 1944 (and later noted climatology professor at the University of Wisconsin-Madison), first predicted 175 mph winds near the 30,000-foot flight level based on arguments similar to those presented in the DataStreme Pressure Blocks Activity 5B. Aircraft actually encountered those winds, confirming the forecast! Carl-Gustav Rossby named these winds the "jet stream" after high speed jets of water that had been studied in the laboratory. Knowledge of these winds is obviously critical for aircraft operations!
Decades of radiosonde data and more recent computer models of atmospheric flows have confirmed that the strength and location of what has become known as the Polar Front jet stream in upper level motions are linked to the formation, movement, and evolution of the Highs and Lows of the surface weather maps. For more detail on some of these relationships, see the optional Thursday Supplemental Summary Information .
To be submitted on the lines for Thursday on the Study Guide, Part B, Applications', Week 9 Chapter Progress Response Form, under section B. Daily Summary.