The polar cap height forecast illustrates the "bottom up" nature of the impending disruption to the polar vortex (i.e. high-latitude blocking) - lower troposphere first, then upper troposphere and lower stratosphere. The 100mb vortex may be record-weak 10 days from now. pic.twitter.com/DZlXC04Xej

— World Climate Service (@WorldClimateSvc) November 26, 2022