Dear Tom,
What is a jet stream and how does it affect weather?
— Bill Brown, Oak Park
Dear Bill,
Jet streams are rivers of wind often several hundred miles across, which have profound effects on the weather. They form in regions across which temperatures vary. The larger the temp spread, the stronger the winds. Jet streams are not of uniform strength and the pockets of stronger winds, known as “jet streaks,” produce vertical motions — both upward and downward — that can affect where storms develop and also where precipitation occurs and the intensity of that precipitation. They contribute to the spin we see in supercell thunderstorms. In addition, the transference of wind energy to the surface plays an important role in the damaging winds we see with thunderstorms. First and foremost, jet streams guide weather movement.
