A dwindling coldest atmosphere creates a greater meandering of the jet stream

~The often used presentation of the jet stream causing weather is nebulous and confusing,
it does not intuitively link current Global Warming as its cause
~ A  laser clear and correct description of the generator of extreme weather simply starts with defining where the coldest atmospheres are located
~The worlds coldest  atmospheric regions are shrinking, stretching  and bending in these days of AGW (Anthropogenic Global Warming),  this explains the sudden extremes in temperatures which often happen in the span of a few days.

     Again and again popular medias fail in describing very clearly what is driving these days of extreme weather,  the failed linkage occurs daily, repeatedly to millions if not billions of people.
The description of jet stream being linked with AGW is correct, but utterly does not explain why.
But rather more accurate would be to present the latest "Polar Vortex"  , which made a recent  news blast,  as a stretched out much weakened  in strength winter zone. Such a definition is more a common sense presentation rendering any unspecialized person, immediately very well informed about climate change implications. 

    I can show TV weather videos,  hundreds of them,  always not educating people as perfectly as they can do about extreme weather correlations.  Is best to present it this way:

University of Maine current day weather, February 14 2019.  500 mb Geopotential levels, pressure heights,  is not the best pressure level to express the Polar Vortex.  600 mb is,  in this standard map, pressure heights confuse where the coldest air lies,   but for sake of this presentation, observe and use your mouse pointer at the limits of lower heights (with mostly colder temperatures) match with the location of the jet stream. The jet stream is a creature which lives at the outside perimeter of coldest air and southern limits of intense cyclones. Therefore by simple projections,  jet stream meanders happen when the coldest atmosphere has a much smaller area:

The day a Polar Vortex froze Chicago and environs still had a stretched out coldest atmosphere.  Properly defined like this:

Again use your mouse pointer and determine where the jet stream starts with respect to coldest air.
Temperatures at 600 mb NOAA daily composites,( map largely in red)   at about -30 C  is where the jet stream is formed. look at Japan's intense jet and how cold 600 mb was at that location.  There are also cyclonic peripheral adjuncts  which extend the coldest atmosphere/jet border line by pressure dropping  the thickness of pressure heights.    Basically January 30 had a stretched out coldest atmosphere.  The jet stream morphed around the coldest air, and did not exactly drag Arctic Air southwards.  Equally, colder temperatures in winter can be created over continents well away from the Arctic, and depend on basic geophysics such as snow cover with little or none  and clear or covered skies under very little insolation ......  WD February 14 2019