Heavy precipitation, wind storms, heat waves—when severe weather events such as these occur they are frequently attributed to a wavy jet stream. The jet stream is a powerful air current in the upper troposphere that balances the pressure gradient and Coriolis forces. It is still not known whether the jet stream is really undergoing changes at decadal timescales and, if so, to what extent.
Click here for original story, Is the jet stream changing?
Source: Phys.org