In reply to broken spectre:
More on the jet stream shifting in New Scientist from 2021
https://www.newscientist.com/article/2289897-shifting-jet-stream-due-to-war...
"Direct observations of this polar jet stream only began a few decades ago thanks to the proliferation of weather satellites, says Osman, so it hasn’t been clear how global warming is affecting it.
Now he and his team have worked out how the average position and intensity of the jet stream over the North Atlantic has changed over the past 1250 years by analysing Greenland ice cores. The position of the jet stream determines storm tracks over the North Atlantic, which in turn determines the temperature of Greenland and how much snow falls there.
The results show that the position and intensity of the jet stream naturally vary a lot. “It seems to be fairly random,” says Osman. Because there is so much variability, global warming hasn’t yet had a discernible effect. The situation is like being on a beach when the tide turns – if the waves are big, it takes time before the rising tide is obvious."
It goes on to say:
"But climate models forecast that the jet stream will shift north as the world warms and the temperature gradient between the Arctic and lower latitudes weakens. Osman’s findings suggest that this effect will start to become obvious from around 2060. By 2100, the average position of the jet stream could be 1 to 3 degrees further north in high-emissions scenarios."
Ultimately, they say, this could lead to drier weather in southern Europe and wetter weather to the north