~The 'Meandering Jet Stream' is basically at its extreme periphery
~It is the Polar Vortex cold air/warm air boundary which causes the jet stream, basically at its extreme periphery
This NOAA 600 mb temperature animation between January 24 to 28 defines the location of the Polar Vortex. It is very stretched out, and has vortices with very cold temperatures which form and disperse in a matter of days. 600 mb is the pressure altitude close to the average temperature of the entire troposphere.
From the Guardian (link here):
"At the moment the vortex looks like two swirling blobs of cold air, one settled over North America, the other over Eurasia,” said Jennifer Francis, the senior scientist at the Woods Hole Research Center. “It splits up when there is sudden stratospheric warming.”
The Polar Stratospheric Vortex has more than 10 times less pressure than the Tropospheric Polar Vortex, its weighted temperature influence is thus at least 10 times less important than temperatures in the lower Troposphere, especially near the ground or sea surface. The warmth over the Arctic Ocean as captured by the NOAA animation above closely depicts where the thinnest sea ice exists , or where the Arctic Ocean open water was at yearly sea ice extent minima in September 2018. The impact of thinner sea ice is obvious here. I have checked the temperatures in the Stratosphere, and they also reflect the heat from thinner sea ice escaping to space, if there was a recent warming, a 10 degree warming can only influence the troposphere below roughly more than 10 times less. WD January 31 2019