This type of chart is a cross section of the entire polar cell, basically. Geopotential height = what altitude in feet is a certain pressure reading. This type of chart has a scale of pressure from top to bottom, and the colors represent height anomalies. Warm air expands and a big area of warm air is high pressure and takes up more space in the atmosphere, so the geopotential height rises
charts can be found here:
https://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.shtmlwatch some Gav's weather vids and Nutrien Ag Solutions forecasts on YouTube and you'll find someone who explains these bits clearly for you
Basically when you look at the Arctic on something like
https://climatereanalyzer.org/reanalysis/daily_maps/ and you see heat anomalies at the surface, pretty sure fire bet there's a high geopotential height anomaly just about directly overhead
We've had a huge geopotential height anomaly over the Arctic for the past 7 months, more than any other year
it comes down to polar vortex destruction pretty much in both hemispheres