Jet Streams and their Importance to Air Navigation

Jet streams are fast moving air streams which appear at times in the levels between 15,000 and 40,000 feet; they are located in the tropical air above the polar front. In this paper examples are given and certain occasions are noted on which they have seriously influenced air navigation. Early in 1948 when a few charts of the 225 mb. level were drawn to show temperature variations over an air route it was noticed that a very strong stream of air was seen along the line where the tropopause appeared to cut that level. This stream seemed of very considerable length and little width.