*************************************** The Jet Stream and Vorticity *************************************** The Jet Stream undulates up and down creating ridges and troughs. The changing of direction of air parcels in the ridges and troughs leads to curvature vorticity. The Jet Stream has its strongest winds at the jet axis, somewhere in the center of the stream. Slower winds are to the right and left of the jet axis. The difference in velocity of winds leads to shear vorticity.