The thing is, this is a chaotic effect of the jet stream going into tighter oscillations. Think of a river in a flat area meandering more and more until oxbows

The thing is, this is a chaotic effect of the jet stream going into tighter oscillations. Think of a river in a flat area meandering more and more until oxbows form. It's an analogous phenomenon with the jet stream and pressure. The jet stream tends to follow warmer air, which means increased temperatures overall give a "flatter" plain to meander on, to return to the analogy. Obviously, like anything, it's far more complex than the analogy permits.