This November's northerlies haven't become "enfeebled" for reasons of a warming world or warming climate or warming Arctic, which you and the other posters suggest. They're simply reflecting the fact that the reservoir of deep cold is present and correct, but, unfortunately, over on the other side of the world:
You posted a chart on the previous Model Output thread from Dec. 1967, pointed out that it's in some ways similar to current ones and asked why the minus 10C isotherm reached France back then, but not this time. The Dec. 1967 chart had the crucial difference though of displaying purple cold 850s over Greenland, which travelled down a narrow lane directly to us; but on the other side of the Pole back then there was nothing like the purple cold temps currently on display.
You can find the two charts, 1967 and 2017, at the bottom of page 51 of the previous Model Output thread.
Originally Posted by: some faraway beach