noun
jet stream
Meteorological term for a narrow band of strong wind in the upper atmosphere.
ジェット気流の影響で飛行時間が短くなった。
The flight time was shortened due to the jet stream.
偏西風 refers specifically to the prevailing westerly winds, while ジェット気流 is the narrow, high-speed core within those winds.
Compound of English loanword ジェット (jet) and 気流 (air current).