I researched how mid lattitude cyclones form and found it has to do with the jet stream, which is above the polar front. The pressure difference between the warm and cold air causes a pressure gradient and is tilted to the right due to the coriolis effect.
How does the jet stream affect weather (e.g. cyclones) in europe? How is it related to the divergence in the jet stream? Also, why is the divergence aloft created? Thanks a lot.